Re: Toward A Better Homebuilt Boat - cat advantages

> Maybe it's just me, but it seems a catamaran's chief benefit is

it's

> ability to carry oversized, high-aspect ratio rig on a light-weigh,
> unballasted hulls(s). Why is this an advantage? Because it means

you

> can go really fast!

Speed is certainly one of the advantages of certain cats, but there
are many more. Unsinkability, in a shoal draft vessel,
circumnavigation ready vessel, that can host a party for 100 is a
composite of some of the advantages.

Cats can have unpleasant motion, they can also keep the coffee right
on a table where it belongs in a nasty storm. Not healing past 5
degrees, lot of reasond

>
> With this advantage come some disadvantages, especially in the
> context of cheap(er) homebuild boats. Perhaps heading the list is

the

> cost/technology needed to put up a big, tall rig. Take away the big
> tall rig, and maybe your back to a sail plan that works nearly as
> well on a monohull (with all the monohull's advantages.)

Actualy a cat is not that well inherantly positioned for a big tall
rig, because there isn't any solid place to step or stay it. It is
perfectly positioned for a nice low tech high efficiency rig, because
it has far better lateral staying, than vertical tensioning ability,
and overall more options than a monohull. So efficient rigs from the
Wharram gaff wingsail, to rotating rigs are cheap.

>
> Now I'll admit, I've contemplated some sort of twin Zephyr

catamaran

> with a modest rig to use as a beach fishing boat that I could use

> take a few people out fishing. The twin hull would let people cast
> and fight fish without worrying about tipping the boat over, and

the

Righ on a boat you can carry, but that could land a tarpon with you
perched on the gunnel. Done right, you make all your noise suspended
over the water. There are picture (they are old and hard to find) of
my BassAckwards over on duckworths, that was designed to do this.
Though mine is mostly for motor. You can use a windsurfer rig on
it.

> modest sail would be easier than rowing. But I have to thing that a
> small sail-plan, low aspect ratio multihull is a speciality boat at
> best.

Not for the first 50 000 years of human evolution.

>
> YIBB,
>
> David
> --
>
> C.E.P.
> 415 W.46th Street
> New York, New York 10036
>http://www.crumblingempire.com
> Mobile (646) 325-8325
> Office (212) 247-0296

FFFB --

Maybe it's just me, but it seems a catamaran's chief benefit is it's
ability to carry oversized, high-aspect ratio rig on a light-weigh,
unballasted hulls(s). Why is this an advantage? Because it means you
can go really fast!

With this advantage come some disadvantages, especially in the
context of cheap(er) homebuild boats. Perhaps heading the list is the
cost/technology needed to put up a big, tall rig. Take away the big
tall rig, and maybe your back to a sail plan that works nearly as
well on a monohull (with all the monohull's advantages.)

Now I'll admit, I've contemplated some sort of twin Zephyr catamaran
with a modest rig to use as a beach fishing boat that I could use to
take a few people out fishing. The twin hull would let people cast
and fight fish without worrying about tipping the boat over, and the
modest sail would be easier than rowing. But I have to thing that a
small sail-plan, low aspect ratio multihull is a speciality boat at
best.

YIBB,

David
--

C.E.P.
415 W.46th Street
New York, New York 10036
http://www.crumblingempire.com
Mobile (646) 325-8325
Office (212) 247-0296

Well, the old story : You can´t have it all :
- Bottoms can be sharp V - shaped (Wharram - style) = no CB or keel
required, good for beaching, no internal space taken, very simple to build,
very strong but a curved rocker exists..
- Bottom flat, hull V-shaped , like a very narrow dory (Waller Coral
Sea) = less rocker but needs keel or CB
- Bottom round or multichine (several designs) = less rocker but requires
CB or keel, more usable width inside available.

Most people using centerboards lower the lee one. A mistake, in my view,
as this certainly favors tipping or pitchpoling.
When I mention this point, I usually meet incredulity
You aren´t making comments about the usually exaggerated sail area and rig
hight on catamarans ?
Frank - Brazil

--- Inbolger@yahoogroups.com, "Frank Sarnighausen" <frankbr@t...>
wrote:

> I´m an old multihull sailor and I disagree with points stated here :
> Pitching or hobbyhorsing can be prevented on the drawing-

board

> by :
> - Creating bow-overhangs with a significative bouyancy reserve

Quite possibly, but on major view these days is that bouyancy is
bouyancy. The reason one sees less of the beautiful old overhangs
are because people figure for a given length (whether WLL of LOA
doesn't mater) the highest PC is a better stategy that bouyancy that
only arises whne the hull is pitched forward. There are two ways a
boat could rock from wave action, one is it is is platform like, and
it moves to the degree that the underlying water moves, basicaly not
much except in a storm, This is the way a multi works side to side,
The other is a movement out of proportion to the actual wave hight,
usualy for and aft. A hobbyhorse is a rocking horse, or rocking
chair. The rockers rock because the rails are curved. If they were
flat they would not rock. A boat with a high central curvature to
its displacement curve is like a rocking chair/horse with curved
rails. To make it impossible to tip over rocking chairs often have a
recurve section at their end. Thid is like the new immersed area
that comes form a bow overhang, a change in the displacemnt curve
shape as the boat rocks forward. Far more efective overall are flat
rails. A flat diplacement curve in the first place.

Another analogy would be the Elegant Punt type hull. It rocks freely
back and forth, until the bow overhang bites in. Is the solution
really making the overhang bigger, or flatening the keel/bottom line
fore and aft?

> - Placing the mast as far back as possible
> - Keeping a slender stern, not full transoms, which would

be lifted

This is contrary to current views, but my boats have fat butts, so I
really don't know.

>
> Pitchpoling can be prevented building a vertically rounded-off
> bow-section of the decks, permitting fast refloating of an

eventually

> submerged bow (never happened to me in boats larger than 7

meters)

Right, and that is the top of the modern bow, all we need is the
bottom as well.

> Frank - Brazil
>
>

Bolger rules!!!
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- To order plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA,
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--- Inbolger@yahoogroups.com, "Frank Sarnighausen" <frankbr@t...>
wrote:

> I´m an old multihull sailor and I disagree with points stated here :
> Pitching or hobbyhorsing can be prevented on the drawing-

board

> by :
> - Creating bow-overhangs with a significative bouyancy reserve

> - Placing the mast as far back as possible
> - Keeping a slender stern, not full transoms, which would

be lifted

This is contrary to current views, but my boats have fat butts, so I
really don't know.

>
> Pitchpoling can be prevented building a vertically rounded-off
> bow-section of the decks, permitting fast refloating of an

eventually

> submerged bow (never happened to me in boats larger than 7

meters)

Right, and that is the top of the modern bow, all we need is the
bottom as well.

> Frank - Brazil
>
>

I´m an old multihull sailor and I disagree with points stated here :
Pitching or hobbyhorsing can be prevented on the drawing-board
by :
- Creating bow-overhangs with a significative bouyancy reserve
- Placing the mast as far back as possible
- Keeping a slender stern, not full transoms, which would be lifted
by following waves.
- Using a low-aspect rig (about as tall as LWL or, maximum, LOA)
which should be as light as possible and carrying a sail area adequate to
the boat´s weight (much smaller than most people think as being right).
- Being an attentive sailor that will reduce sail as soon as overpowering
manifests itself

Pitchpoling can be prevented building a vertically rounded-off
bow-section of the decks, permitting fast refloating of an eventually
submerged bow (never happened to me in boats larger than 7 meters)
Frank - Brazil

--- Inbolger@yahoogroups.com, "pvanderwaart <pvanderw@o...>"
<pvanderw@o...> wrote:

> > The form stability of a multihull cause them to pitch
> > more violently than a monohull. If a multihull does not pitch,
> > then it will be the result of insufficient bouyancy forward and
> > will eventually pitchpole like a Hobie 16.
>
> I am not sure I understand your point. Clearly, multihulls

pitchpole

> more often than monohulls. I always thought it was because a)
> buoyancy in the bow as reduced as much as possible to reduce
> resistance in waves, and 2) multis tend to have big, heavy rigs.

(Rig

> weight is a much bigger percentage of all-up weight than in a
> ballasted monohull.) I can see that in a multi that does pitch a

lot,

> the crew would have warning that the boat is overpressed, but in
> multi that does not pitch a lot, you could be near the pitchpole
> point and not realize it. Is this your meaning? Or is there some

> complex phenomenon?
>
> Peter

I think ealier multis pitched because they hadn't any bouyancy
forward, or aft, double ended knives. Then they added full transoms,
and they would still pitch a little, but forward, with a jerky
motion. Now they are fuller forward and aft, and that seems to have
reduced the problem a lot. Pure shapes allow low resistance with
full ends.

Pitchpoling I think has a lot to do with racing. Sailing at 20 knots
in heavy waves,upwind, singlehanded, on enormous boats can be risky.
In some of the footage I have seen, the boats are repeatedly airborn,
leaping off waves. Racing is trying to find the close edge of
disaster, sometimes you go over it.

The other factor is that in the early days people like Piver, who was
a surfer, openly spoke of surfing little nocked together multihulls,
down the face of storm waves, as a go-fast strategy. He basicaly was
advising rank amateurs to perform in a fashion we see only today with
profesional crews, in the southern oceans. There is some evidence he
could do that kind of thing and make it work. A visionary on many
levels. But the storm strategy today is to throw out the sea anchor
and turn on the TV, eat some microwave popcorn. One lives longer.

Bolger rules!!!
- no cursing, flaming, trolling, spamming, or flogging dead horses
- stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
- add your comments at the TOP and SIGN your posts and <snip> away
- To order plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA,
01930, Fax: (978) 282-1349
- Unsubscribe:bolger-unsubscribe@yahoogroups.com
- Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com

Your use of Yahoo! Groups is subject tohttp://docs.yahoo.com/info/terms/

--- Inbolger@yahoogroups.com, "pvanderwaart <pvanderw@o...>"
<pvanderw@o...> wrote:

> > The form stability of a multihull cause them to pitch
> > more violently than a monohull. If a multihull does not pitch,
> > then it will be the result of insufficient bouyancy forward and
> > will eventually pitchpole like a Hobie 16.
>
> I am not sure I understand your point. Clearly, multihulls

pitchpole

> more often than monohulls. I always thought it was because a)
> buoyancy in the bow as reduced as much as possible to reduce
> resistance in waves, and 2) multis tend to have big, heavy rigs.

(Rig

> weight is a much bigger percentage of all-up weight than in a
> ballasted monohull.) I can see that in a multi that does pitch a

lot,

> the crew would have warning that the boat is overpressed, but in
> multi that does not pitch a lot, you could be near the pitchpole
> point and not realize it. Is this your meaning? Or is there some

> complex phenomenon?
>
> Peter

>
> > - The trimaran is, above all else, stable and roomy.

What are we talking about? 12'? 36'? 60? There is no absolute
comparison of tri, cat, pro, mono. Their relative advantages are
completely relative to scale, as well as other factors.

>
> Stable, yes, and roomy, yes, on deck, that is. Due to the narrow
> hulls required to make them seaworthy and fast, you won't find any
> with reasonable inside room until you get about 30 ft. in length.

> that point it would be cumbersome to trailer.

This is truer of the Wharram you were involved with than all tris or
cats. You can easily design a cat or tri in the 16'-18' with
significant room. We have been giving it a big try over on the Multi
Boatbuilding forum, wiht the additional specification that it needs
to be as easy to launch as a bassboat.

>
> > - It is fast.
>
> Yep. No doubt about that. Speed will increase your cruising

area.

> However, speed will be a detriment if you encounter a solid object

> the water, like a log, debris, or unlit buoy. And with all the

trash

> in the oceans, hitting something is becoming more and more likely.

That is a seamanship issue don't go fast where the risk of collision
is greattest. Big advantage of the multi is that it will ghost
exceptionaly well, and won't sink like an anchor in a crash.

> All true. The form stability of a multihull cause them to pitch

> violently than a monohull. If a multihull does not pitch, then it
> will be the result of insufficient bouyancy forward and will
> eventually pitchpole like a Hobie 16.

Well one of the strategies is lots of bouyancy forward, if you look
at recent designs over the last 15 years, the PC has risen from
about.55 to .6-.8. That kills both pitching and bow burying, though
the quickness of any movement may still be apparent.

>
> >
> > Here are some other pluses which could be designed in:
> >
> > - Light weight. A trimaran could be designed in which each hull

> light
> > enough to be cartopped, together with crossbeams and mast(s).
> > - Folding or telescoping crossbeams to make docking simpler
> (although, a
> > trimaran of this kind is best treated like a beach cat).

I think it is best to think in terms of a trailer. There are 16
footers that sleep four, but they can't be caretopped.

Any demount/fold mechanisms usualy cost and take time equal to the
boat's cost and build, except when the result is very slow to set
up. The exception are the few designs that are trailer width at all
times.

> > also be easily reefed or furled. For example, the main sail could
> be furled
> > on the boom and the head sail could be roller furling (not
> necessarily roller
> > reefing, which is a whole other complication). Or a cat ketch
> design could be
> > used and both sails furled on the masts. Masts could be sectional
> for ease of
> > transport and storage.

WHat size are we talking these things are a necesity on some sizes
and way to much trouble on smaller boats.

>
> This is the case on monohulls also. Ease of sail management allows
> for less fatiguing passages, regardless of vessel size or type.
> Chris White particularly likes the cat ketch sail plan. Sectional
> masts are not as strong so must be made heavier, which defeats the
> purpose. But if you have 2 masts, they can be shorter than a

single

> mast. James Wharram rarely designs his cats with masts longer than
> the boat.
>
> > - Some creativity and invention could be applied to the board or
> boards.
> > Perhaps a leeboard mounted on the main hull would be best and
> easiest to
> > build or could the outside hulls be built with full keels the
> length of the
> > hull but not very deep?
>
> Full keels increase wetted surface, which makes a multihull much

> sticky in lighter air. I would go with a centerboard or

daggerboard

> if carefully designed. Because of the higher speeds you need to be
> careful with the appendages.

They could be purple or they could be blue, what is the design brief?

>
> >
> > I think these thoughts form the parameters of a very clever,
> convenient,
> > high-performance boat which would be relatively easy to build,
> launch, sail,
> > retrieve, transport and store. Unfortunately, in my opinion, this
> kind of
> > boat has not been much explored.

The last point is certainly not true. If we are talking the short
end of the spectrum, a huge number of designs have been tried

>
> It has, but there are a number of barriers having to do with
> homebuilder expertise, materials, and type of boat. For ease of
> construction, Wharram wins hands-down. But his boats are fairly
> conservative and not exactly speedsters. Jim Brown is next with

the

> old Searunner series, again fairly conservative and the smallest is
> around 25 ft. If you want better performance, then you start

looking

> at more complex shapes like tortured plywood, Constant Camber, and
> cedar strip, all which are daunting to most neophytes.

I don't agree that Wharram wins hands down on ease of construction.
His small boats somewhat, by the time one hits 30 feet, there are
some serious building flaws, and they use large amounts of materials,
which raises labour and cost. I agree about the dauntingness up
front, of things like tortured ply, but they can be much faster to
build, and possibly easier, if you are willing to practice a few
scarfs, or buy a scarfer. Amateurs are rightfuly concerned with ease
of build, but there can be hidden problems, that actually are bigger
than the ones that declare themselves with the plans. Vacuum bagging
and torturing my Hughes proved easy, but the roofline that was
uncompoundable was not easy, though if I had know it couldn't be
compounded there would have been a number of easy ways to build it.

Seaclippers are easier than searunners.

>
> >
> > The Bolger method of boat building has taught all of us the

basics

> for
> > designing this kind of boat and rig, so...
> > Are there any designers out there up to the challenge?
>
> There are 2 more significant issues that I'll bring up here.
>
> The first is carrying capacity. Multihulls are built light and are
> intended to stay light for the best seaworthiness. As a result you
> can't load them down much with stores or people. Wharram and
> Brown/Marples have addressed some of this by hull shape, but there
> are still limits. Monohulls are not affected as significantly.

Carrying capacity is totaly key. If what you want is a small boat
with a lot of room, and you don't want it to be a real speedster,
then go to 6-1 hull shapes. Farrier had a great little try like
that, unfortunately he has withdrawn the plans.

>
> The second is construction. No matter how you look at it, when you
> build a trimaran you are building three boats. The building time

and

> finances required have to be figured as such. If you have a limit

> space, as I did, that can also be difficult.

It can certainly be a problem. I'm building a proa. Probably. I do
think that one could build the hulls for a small try a sixteen
footer, in a weekend. On larger tris Like My 24 footer, I got it
down to 20 hours, but the first one took a lot longer. There are a
lot of complexities.

>
> As for designers, I've already mentioned Wharram and Brown for
> obvious reasons. Both of them have done a fantastic job of

designing

> boats that can be built in developing nations (both have travelled
> extensively to help poor communities) with local wood and few
> resources. Farrier concluded that conventional plywood made the

boat

> too heavy so branched into cedar strip and other complex shapes.

He may still have designed the best small tris ever. The market
moved him to the complex shapes.

> Other multihull designers, like Kelsall, Shuttleworth, Kendrick,
> Newick, and White start getting into complexities that are beyond
> most homebuilders.

I really don't agree with that, though again it depends on what scale
we are talking, and certainly these boats aren't getting easier to
build, but them the average cruiser these days wants a 40' catamaran!!

Newick has the best small tris I have seen, the Tremolino, and the
Argonauta/B2. The latter is strip, but if you ask for it in plywood
I bet he will design it. Kelsal's swift sandwich I am not totaly
sold on, and it wouldn't be economic in my mind on the short end, but
home builders appear to flock to it, and seminars are available. I
don't know Kendrick, but he appears to be bridging towards some of
the more complex shapes with plywood. Not Bolger boxes, however.
White is just taking the usual contractors route of starting with the
equivalent of a small reno job, and ending up doing custom houses.
His new designs are admitedly expensive, his older ones were pretty
nice and easy.

Bolger seems to have a thing for multis, like Hereshoff, nice to see
a few other Bolgaristas with good ideas on the subject.

>
> Jack

I found that as in Tri's that catamarans have the same problem in
the big chop because of the sail and mast weight up high. In chop it
shakes the shape out of the sail reducing forward speed and power. I
bought a new carbon fiber mast and light sails with carbon fiber
battens and it helped greatly but my bows still punctured the waves
and did not raise over them. It is faster in chop but not as fast a
the same size sail area on a Mono hull going to weather.

John

--- Inbolger@yahoogroups.com, "lulalake_1999 <lulalake_1999@y...>"
<lulalake_1999@y...> wrote:

> Hi Jack,
>
> My first "larger" boat was a 70's era 25' Horstman tri. An

excellent

> boat, three layers, cold molded. One more issue is that in moderate
> chop (moderate in relation to the boat size), along with low to
> moderate wind speed, tri's don't do to well. Again, you have three
> hulls pushing against short, steep waves with the sail area of one
> boat.
>
> Jules
>
>
> --- Inbolger@yahoogroups.com, "egiajack <jgclayt@e...>"
> <jgclayt@e...> wrote:
> > As a homebuilder, and as a former multihull builder, I am

compelled

> > to respond to continue the debate. I chose to build a Wharram

Tiki

> > 21 many years ago. I failed to complete it for a variety of
> reasons,
> > but went on to complete an 18 ft. sharpie.
> >
> > You are correct that there are many advantages to multihulls, and
> I'm
> > certainly a proponent of them depending on the type of sailing

you

> > want to do.
> >
> >
> > > - The trimaran is, above all else, stable and roomy.
> >
> > Stable, yes, and roomy, yes, on deck, that is. Due to the narrow
> > hulls required to make them seaworthy and fast, you won't find

any

> > with reasonable inside room until you get about 30 ft. in

length.

> At
> > that point it would be cumbersome to trailer.
> >
> > > - It is fast.
> >
> > Yep. No doubt about that. Speed will increase your cruising
> area.
> > However, speed will be a detriment if you encounter a solid

object

> in
> > the water, like a log, debris, or unlit buoy. And with all the
> trash
> > in the oceans, hitting something is becoming more and more likely.
> >
> > > - It is versatile, being perfectly able under sail, power and,

> > cleverly
> > > designed, under paddle or oar.
> > > - It is a safe form, not only resisting capsize but offering
> three
> > separate
> > > hulls for floatation in the worst case scenario.
> > > - It is easy to climb in and out of.
> > > - It can offer very comfortable seating while underway.
> > > - It is safe to stand up in and move about.
> >
> > All true. The form stability of a multihull cause them to pitch
> more
> > violently than a monohull. If a multihull does not pitch, then

> > will be the result of insufficient bouyancy forward and will
> > eventually pitchpole like a Hobie 16.
> >
> > >
> > > Here are some other pluses which could be designed in:
> > >
> > > - Light weight. A trimaran could be designed in which each hull
> is
> > light
> > > enough to be cartopped, together with crossbeams and mast(s).
> > > - Folding or telescoping crossbeams to make docking simpler
> > (although, a
> > > trimaran of this kind is best treated like a beach cat).
> >
> > Better make it a really small beach cat. Wharram's 14 ft. cat is
> > cartoppable, but his bigger ones are not.
> >
> > > - A rig could be designed which maximizes speed and ease of
> sailing
> > and can
> > > also be easily reefed or furled. For example, the main sail

could

> > be furled
> > > on the boom and the head sail could be roller furling (not
> > necessarily roller
> > > reefing, which is a whole other complication). Or a cat ketch
> > design could be
> > > used and both sails furled on the masts. Masts could be

sectional

> > for ease of
> > > transport and storage.
> >
> > This is the case on monohulls also. Ease of sail management

allows

> > for less fatiguing passages, regardless of vessel size or type.
> > Chris White particularly likes the cat ketch sail plan.

Sectional

> > masts are not as strong so must be made heavier, which defeats

the

> > purpose. But if you have 2 masts, they can be shorter than a
> single
> > mast. James Wharram rarely designs his cats with masts longer

than

> > the boat.
> >
> > > - Some creativity and invention could be applied to the board

> > boards.
> > > Perhaps a leeboard mounted on the main hull would be best and
> > easiest to
> > > build or could the outside hulls be built with full keels the
> > length of the
> > > hull but not very deep?
> >
> > Full keels increase wetted surface, which makes a multihull much
> more
> > sticky in lighter air. I would go with a centerboard or
> daggerboard
> > if carefully designed. Because of the higher speeds you need to

> > careful with the appendages.
> >
> > >
> > > I think these thoughts form the parameters of a very clever,
> > convenient,
> > > high-performance boat which would be relatively easy to build,
> > launch, sail,
> > > retrieve, transport and store. Unfortunately, in my opinion,

this

> > kind of
> > > boat has not been much explored.
> >
> > It has, but there are a number of barriers having to do with
> > homebuilder expertise, materials, and type of boat. For ease of
> > construction, Wharram wins hands-down. But his boats are fairly
> > conservative and not exactly speedsters. Jim Brown is next with
> the
> > old Searunner series, again fairly conservative and the smallest

> > around 25 ft. If you want better performance, then you start
> looking
> > at more complex shapes like tortured plywood, Constant Camber,

and

> > cedar strip, all which are daunting to most neophytes.
> >
> > >
> > > The Bolger method of boat building has taught all of us the
> basics
> > for
> > > designing this kind of boat and rig, so...
> > > Are there any designers out there up to the challenge?
> >
> > There are 2 more significant issues that I'll bring up here.
> >
> > The first is carrying capacity. Multihulls are built light and

are

> > intended to stay light for the best seaworthiness. As a result

you

> > can't load them down much with stores or people. Wharram and
> > Brown/Marples have addressed some of this by hull shape, but

there

> > are still limits. Monohulls are not affected as significantly.
> >
> > The second is construction. No matter how you look at it, when

you

> > build a trimaran you are building three boats. The building time
> and
> > finances required have to be figured as such. If you have a

limit

> on
> > space, as I did, that can also be difficult.
> >
> > As for designers, I've already mentioned Wharram and Brown for
> > obvious reasons. Both of them have done a fantastic job of
> designing
> > boats that can be built in developing nations (both have

travelled

> > extensively to help poor communities) with local wood and few
> > resources. Farrier concluded that conventional plywood made the
> boat
> > too heavy so branched into cedar strip and other complex shapes.
> > Other multihull designers, like Kelsall, Shuttleworth, Kendrick,
> > Newick, and White start getting into complexities that are beyond
> > most homebuilders.
> >
> > Jack

This one is able to cartop and is very fast, you can use is as a
very fast daysailer.

http://www.dngoodchild.com/5095.htm

I would never build one but it is a tri at heart and if you need
speed you have the best of both worlds

John

--- Inbolger@yahoogroups.com, "Gary Lepak" <gnjlepak@o...> wrote:
> I think you make a lot of good points about tris as daysailers.
They have
> the stability and safe to be relaxing and comfortable to sail. For
> cartopping the size will be limited by how big and heavy a hull you
are
> willing to cartop. This tri was built with a used canoe for a main
hull,
> and if you didn't add the cabin it would be cartoppable.
>http://www.duckworksmagazine.com/projects/banane/banane.htm
>
> For quick homebuilding I would go along the lines of Bolger's
Tarantula
> trimaran in BWAOM chapter 31. At 23' it would not be cartoppable,
but just
> reduce the main hull size to what you want. I would use simple V
shaped
> floats instead of flat bottomed, more seakindly and even easier
to build.
> Build it so that at rest the floats are both out of the water, and
you can
> use crew weight to sail it level in light winds and keep down wetted
> surface. I would use a leeboard or daggerboard in the main hull.
It could
> be designed to use a used Hobie cat rig to save on sails. Or
windsurfer
> rigs as in the above link.
>
> Another possibility is starting with a kayak main hull, though
probably
> makes a smaller tri than you are thinking of. Go to
>http://www.clcboats.com/then scroll down to pics.
>
> I think there are a lot of good ideas out there already, but as you
say room
> for more possibilities. One thing to work on is making it really
quick to
> get from the cartop to the water.
>
> Gary Lepak

Peter,

> I can see that in a multi that does pitch a lot,
> the crew would have warning that the boat is overpressed, but in
> multi that does not pitch a lot, you could be near the pitchpole
> point and not realize it. Is this your meaning? Or is there some

> complex phenomenon?

Yes, you got it right. I mentioned the Hobie 16 because it has a
notorious reputation for pitchpoling. Despite its popularity, it was
a very early design and had a few flaws. Later designs by Hobie,
Nacra, Prindle, etc. contain fuller bow sections that rise over waves
rather than "augering in."

Jack

> The form stability of a multihull cause them to pitch
> more violently than a monohull. If a multihull does not pitch,
> then it will be the result of insufficient bouyancy forward and
> will eventually pitchpole like a Hobie 16.

I am not sure I understand your point. Clearly, multihulls pitchpole
more often than monohulls. I always thought it was because a)
buoyancy in the bow as reduced as much as possible to reduce
resistance in waves, and 2) multis tend to have big, heavy rigs. (Rig
weight is a much bigger percentage of all-up weight than in a
ballasted monohull.) I can see that in a multi that does pitch a lot,
the crew would have warning that the boat is overpressed, but in
multi that does not pitch a lot, you could be near the pitchpole
point and not realize it. Is this your meaning? Or is there some more
complex phenomenon?

Peter

Hi Jack,

My first "larger" boat was a 70's era 25' Horstman tri. An excellent
boat, three layers, cold molded. One more issue is that in moderate
chop (moderate in relation to the boat size), along with low to
moderate wind speed, tri's don't do to well. Again, you have three
hulls pushing against short, steep waves with the sail area of one
boat.

Jules

--- Inbolger@yahoogroups.com, "egiajack <jgclayt@e...>"
<jgclayt@e...> wrote:

> As a homebuilder, and as a former multihull builder, I am compelled
> to respond to continue the debate. I chose to build a Wharram Tiki
> 21 many years ago. I failed to complete it for a variety of

reasons,

> but went on to complete an 18 ft. sharpie.
>
> You are correct that there are many advantages to multihulls, and

I'm

> certainly a proponent of them depending on the type of sailing you
> want to do.
>
>
> > - The trimaran is, above all else, stable and roomy.
>
> Stable, yes, and roomy, yes, on deck, that is. Due to the narrow
> hulls required to make them seaworthy and fast, you won't find any
> with reasonable inside room until you get about 30 ft. in length.

> that point it would be cumbersome to trailer.
>
> > - It is fast.
>
> Yep. No doubt about that. Speed will increase your cruising

area.

> However, speed will be a detriment if you encounter a solid object

> the water, like a log, debris, or unlit buoy. And with all the

trash

> in the oceans, hitting something is becoming more and more likely.
>
> > - It is versatile, being perfectly able under sail, power and, if
> cleverly
> > designed, under paddle or oar.
> > - It is a safe form, not only resisting capsize but offering

three

> separate
> > hulls for floatation in the worst case scenario.
> > - It is easy to climb in and out of.
> > - It can offer very comfortable seating while underway.
> > - It is safe to stand up in and move about.
>
> All true. The form stability of a multihull cause them to pitch

> violently than a monohull. If a multihull does not pitch, then it
> will be the result of insufficient bouyancy forward and will
> eventually pitchpole like a Hobie 16.
>
> >
> > Here are some other pluses which could be designed in:
> >
> > - Light weight. A trimaran could be designed in which each hull

> light
> > enough to be cartopped, together with crossbeams and mast(s).
> > - Folding or telescoping crossbeams to make docking simpler
> (although, a
> > trimaran of this kind is best treated like a beach cat).
>
> Better make it a really small beach cat. Wharram's 14 ft. cat is
> cartoppable, but his bigger ones are not.
>
> > - A rig could be designed which maximizes speed and ease of

sailing

> and can
> > also be easily reefed or furled. For example, the main sail could
> be furled
> > on the boom and the head sail could be roller furling (not
> necessarily roller
> > reefing, which is a whole other complication). Or a cat ketch
> design could be
> > used and both sails furled on the masts. Masts could be sectional
> for ease of
> > transport and storage.
>
> This is the case on monohulls also. Ease of sail management allows
> for less fatiguing passages, regardless of vessel size or type.
> Chris White particularly likes the cat ketch sail plan. Sectional
> masts are not as strong so must be made heavier, which defeats the
> purpose. But if you have 2 masts, they can be shorter than a

single

> mast. James Wharram rarely designs his cats with masts longer than
> the boat.
>
> > - Some creativity and invention could be applied to the board or
> boards.
> > Perhaps a leeboard mounted on the main hull would be best and
> easiest to
> > build or could the outside hulls be built with full keels the
> length of the
> > hull but not very deep?
>
> Full keels increase wetted surface, which makes a multihull much

> sticky in lighter air. I would go with a centerboard or

daggerboard

> if carefully designed. Because of the higher speeds you need to be
> careful with the appendages.
>
> >
> > I think these thoughts form the parameters of a very clever,
> convenient,
> > high-performance boat which would be relatively easy to build,
> launch, sail,
> > retrieve, transport and store. Unfortunately, in my opinion, this
> kind of
> > boat has not been much explored.
>
> It has, but there are a number of barriers having to do with
> homebuilder expertise, materials, and type of boat. For ease of
> construction, Wharram wins hands-down. But his boats are fairly
> conservative and not exactly speedsters. Jim Brown is next with

the

> old Searunner series, again fairly conservative and the smallest is
> around 25 ft. If you want better performance, then you start

looking

> at more complex shapes like tortured plywood, Constant Camber, and
> cedar strip, all which are daunting to most neophytes.
>
> >
> > The Bolger method of boat building has taught all of us the

basics

> for
> > designing this kind of boat and rig, so...
> > Are there any designers out there up to the challenge?
>
> There are 2 more significant issues that I'll bring up here.
>
> The first is carrying capacity. Multihulls are built light and are
> intended to stay light for the best seaworthiness. As a result you
> can't load them down much with stores or people. Wharram and
> Brown/Marples have addressed some of this by hull shape, but there
> are still limits. Monohulls are not affected as significantly.
>
> The second is construction. No matter how you look at it, when you
> build a trimaran you are building three boats. The building time

and

> finances required have to be figured as such. If you have a limit

> space, as I did, that can also be difficult.
>
> As for designers, I've already mentioned Wharram and Brown for
> obvious reasons. Both of them have done a fantastic job of

designing

> boats that can be built in developing nations (both have travelled
> extensively to help poor communities) with local wood and few
> resources. Farrier concluded that conventional plywood made the

boat

> too heavy so branched into cedar strip and other complex shapes.
> Other multihull designers, like Kelsall, Shuttleworth, Kendrick,
> Newick, and White start getting into complexities that are beyond
> most homebuilders.
>
> Jack

I think you make a lot of good points about tris as daysailers. They have
the stability and safe to be relaxing and comfortable to sail. For
cartopping the size will be limited by how big and heavy a hull you are
willing to cartop. This tri was built with a used canoe for a main hull,
and if you didn't add the cabin it would be cartoppable.
http://www.duckworksmagazine.com/projects/banane/banane.htm

For quick homebuilding I would go along the lines of Bolger's Tarantula
trimaran in BWAOM chapter 31. At 23' it would not be cartoppable, but just
reduce the main hull size to what you want. I would use simple V shaped
floats instead of flat bottomed, more seakindly and even easier to build.
Build it so that at rest the floats are both out of the water, and you can
use crew weight to sail it level in light winds and keep down wetted
surface. I would use a leeboard or daggerboard in the main hull. It could
be designed to use a used Hobie cat rig to save on sails. Or windsurfer
rigs as in the above link.

Another possibility is starting with a kayak main hull, though probably
makes a smaller tri than you are thinking of. Go to
http://www.clcboats.com/then scroll down to pics.

I think there are a lot of good ideas out there already, but as you say room
for more possibilities. One thing to work on is making it really quick to
get from the cartop to the water.

Gary Lepak

As a homebuilder, and as a former multihull builder, I am compelled
to respond to continue the debate. I chose to build a Wharram Tiki
21 many years ago. I failed to complete it for a variety of reasons,
but went on to complete an 18 ft. sharpie.

You are correct that there are many advantages to multihulls, and I'm
certainly a proponent of them depending on the type of sailing you
want to do.

> - The trimaran is, above all else, stable and roomy.

Stable, yes, and roomy, yes, on deck, that is. Due to the narrow
hulls required to make them seaworthy and fast, you won't find any
with reasonable inside room until you get about 30 ft. in length. At
that point it would be cumbersome to trailer.

> - It is fast.

Yep. No doubt about that. Speed will increase your cruising area.
However, speed will be a detriment if you encounter a solid object in
the water, like a log, debris, or unlit buoy. And with all the trash
in the oceans, hitting something is becoming more and more likely.

> - It is versatile, being perfectly able under sail, power and, if

cleverly

> designed, under paddle or oar.
> - It is a safe form, not only resisting capsize but offering three

separate

> hulls for floatation in the worst case scenario.
> - It is easy to climb in and out of.
> - It can offer very comfortable seating while underway.
> - It is safe to stand up in and move about.

All true. The form stability of a multihull cause them to pitch more
violently than a monohull. If a multihull does not pitch, then it
will be the result of insufficient bouyancy forward and will
eventually pitchpole like a Hobie 16.

>
> Here are some other pluses which could be designed in:
>
> - Light weight. A trimaran could be designed in which each hull is

light

> enough to be cartopped, together with crossbeams and mast(s).
> - Folding or telescoping crossbeams to make docking simpler

(although, a

> trimaran of this kind is best treated like a beach cat).

Better make it a really small beach cat. Wharram's 14 ft. cat is
cartoppable, but his bigger ones are not.

> - A rig could be designed which maximizes speed and ease of sailing

and can

> also be easily reefed or furled. For example, the main sail could

be furled

> on the boom and the head sail could be roller furling (not

necessarily roller

> reefing, which is a whole other complication). Or a cat ketch

design could be

> used and both sails furled on the masts. Masts could be sectional

for ease of

> transport and storage.

This is the case on monohulls also. Ease of sail management allows
for less fatiguing passages, regardless of vessel size or type.
Chris White particularly likes the cat ketch sail plan. Sectional
masts are not as strong so must be made heavier, which defeats the
purpose. But if you have 2 masts, they can be shorter than a single
mast. James Wharram rarely designs his cats with masts longer than
the boat.

> - Some creativity and invention could be applied to the board or

boards.

> Perhaps a leeboard mounted on the main hull would be best and

easiest to

> build or could the outside hulls be built with full keels the

length of the

> hull but not very deep?

Full keels increase wetted surface, which makes a multihull much more
sticky in lighter air. I would go with a centerboard or daggerboard
if carefully designed. Because of the higher speeds you need to be
careful with the appendages.

>
> I think these thoughts form the parameters of a very clever,

convenient,

> high-performance boat which would be relatively easy to build,

launch, sail,

> retrieve, transport and store. Unfortunately, in my opinion, this

kind of

> boat has not been much explored.

It has, but there are a number of barriers having to do with
homebuilder expertise, materials, and type of boat. For ease of
construction, Wharram wins hands-down. But his boats are fairly
conservative and not exactly speedsters. Jim Brown is next with the
old Searunner series, again fairly conservative and the smallest is
around 25 ft. If you want better performance, then you start looking
at more complex shapes like tortured plywood, Constant Camber, and
cedar strip, all which are daunting to most neophytes.

>
> The Bolger method of boat building has taught all of us the basics

for

> designing this kind of boat and rig, so...
> Are there any designers out there up to the challenge?

There are 2 more significant issues that I'll bring up here.

The first is carrying capacity. Multihulls are built light and are
intended to stay light for the best seaworthiness. As a result you
can't load them down much with stores or people. Wharram and
Brown/Marples have addressed some of this by hull shape, but there
are still limits. Monohulls are not affected as significantly.

The second is construction. No matter how you look at it, when you
build a trimaran you are building three boats. The building time and
finances required have to be figured as such. If you have a limit on
space, as I did, that can also be difficult.

As for designers, I've already mentioned Wharram and Brown for
obvious reasons. Both of them have done a fantastic job of designing
boats that can be built in developing nations (both have travelled
extensively to help poor communities) with local wood and few
resources. Farrier concluded that conventional plywood made the boat
too heavy so branched into cedar strip and other complex shapes.
Other multihull designers, like Kelsall, Shuttleworth, Kendrick,
Newick, and White start getting into complexities that are beyond
most homebuilders.

Jack

Teakdeck,

I think it might be most enlightening and useful if you would sit
down and make a similar list of the disadvantages of the various
thoughts and ideas that you proposed. You have proposed not one,
but many different boats here.

If this list is very short, then you may need to spend more time
studying and thinking. By the way, I like trimarans and have been
involved with building, rigging and sailing a small (20 foot) one.
There are tons of downsides to balance against the plusses to be
considered.

I am convinced the trimaran form of hull and rig provide the least compromise
and greatest rewards for the home builder of small sailboats. The reasons are
many:

- The trimaran is, above all else, stable and roomy.
- It is fast.
- It is versatile, being perfectly able under sail, power and, if cleverly
designed, under paddle or oar.
- It is a safe form, not only resisting capsize but offering three separate
hulls for floatation in the worst case scenario.
- It is easy to climb in and out of.
- It can offer very comfortable seating while underway.
- It is safe to stand up in and move about.

Here are some other pluses which could be designed in:

- Light weight. A trimaran could be designed in which each hull is light
enough to be cartopped, together with crossbeams and mast(s).
- Folding or telescoping crossbeams to make docking simpler (although, a
trimaran of this kind is best treated like a beach cat).
- A rig could be designed which maximizes speed and ease of sailing and can
also be easily reefed or furled. For example, the main sail could be furled
on the boom and the head sail could be roller furling (not necessarily roller
reefing, which is a whole other complication). Or a cat ketch design could be
used and both sails furled on the masts. Masts could be sectional for ease of
transport and storage.
- Some creativity and invention could be applied to the board or boards.
Perhaps a leeboard mounted on the main hull would be best and easiest to
build or could the outside hulls be built with full keels the length of the
hull but not very deep?

I think these thoughts form the parameters of a very clever, convenient,
high-performance boat which would be relatively easy to build, launch, sail,
retrieve, transport and store. Unfortunately, in my opinion, this kind of
boat has not been much explored.

The Bolger method of boat building has taught all of us the basics for
designing this kind of boat and rig, so...
Are there any designers out there up to the challenge?