Re: [bolger] Re: "Box-boat" rocker planning

Hi Graeme,

I have a bit experience with a test-proa and flying ama: Never again on a lake!
Maybe between two islands with a more or less constant wind as one can expect between pacific ilands. Will say: No shunting please!

I only have the Bolger Book "Boats with open mind", "The Sharpie Book" from Parker and "American Small Sailing craft" from Chapelle. The last one is a really good one. But I do not have a source of information regarding planing flat bottom boats. Most of the flat bottom designs show a remakable rocker in the stern region, also the older garveys, and I understand this as a necessary detail to avoid a slamming (dragging deep) corner of the stern when heeled. On the other hand this detail (instead of a double ended boat) makes planing rather difficult to reach.

So: I'm looking for someone, who has experience with a flatbottomed boat like the JuneBug with vertical sides with a bit more sailpower and in the planing modus. I do not want to make all possible mistakes, which can be build in in such a Boxboat. Especially regarding the rocker and the distribution of it. And the not known necessity of this short "keels", most of thos boats show in the stern region.

Best regards


Dieter



"graeme19121984" <graeme19121984@...> schrieb:

> <
> Hi Dieter,
>
> Im aware many owners have commented on PCB boats in that size range
> planing: eg Gypsy, Surf, the scooners,and most commonly Windsprint.
>
> However if the envelope is stretched a little, what about the
> 19'6"x20"(x 10'6" overall beam) Minimum Proa. It has to fly; maybe
> change the rig to jib headed cat ketch ( 2 x 59sqft sprit boom? )
> Perhaps , if you like, leave off the ama and have a hiking baord.
>
> And what is going on with Anhinga? I've looked at those lines long
> and hard: double ended for sailing and rowing, but with a slight
> rocker in the forward third then dead flat aft. Like the long narrow
> low powered planing designs,or the hulls of Fishcat, or Fast Brick?
> Maybe not the beam in the quarter, but there's length.
>
> Ideas anyone?
>
> Regards
> Graeme
>
>
>
> --- Inbolger@yahoogroups.com, "John B. Trussell"
> <John.Trussell@w...> wrote:
> > Dieter--Welcome.   In any user group, you must accept that much of
> what is said is based on having read others' opinions and much of
> what is stated as fact is likely to be opinion.  This is a long way
> of saying that I'm not totally certain, but I think....
> >
> > Flat bottomed boats need rocker if they are to operate at
> displacement speeds, They should have little or no rocker if they
> are intended to operate at planing speeds (but such boats will not
> perform well at displacement speeds).
> >
> > A problem which flat bottomed boats have when they are moving
> through the water and heeled is that the curve of the bottom and the
> curve of the sides are diffferent.  Therefore the water moves more
> quickly over the side than over the bottom.  This, in turn creates
> drag inducing eddies at the chine.
> >
> > If I understand it correctly, Bolger has, in his "box boats",
> attempted to match the curve of the bottom to the curve in the side,
> thereby eliminating the eddies.
> >
> > If you wish to produce a fast "box boat", you might want to
> consider building a wide, shallow boat which could be sailed at a
> considerable angle of heel.  The result would be similiar to sailing
> scows and several scow shaped development classes--notably the
> International Moth.
> >
> > Good luck.
> >
> > John T
> >   ----- Original Message -----
> >   From: dietermschulz
> >   To:bolger@yahoogroups.com
> >   Sent: Monday, October 04, 2004 11:35 AM
> >   Subject: [bolger] "Box-boat" rocker planning
> >
> >
> >
> >   Hi, I'm new in this group, a rather experienced dinghy sailor,
> living
> >   in Munich germany. My question:
> >
> >
> >   The typical box-boat designs of Philip C. Bolger without flare
> of the
> >   sides, like June Bug(?), show a more or less remarkable rocker.
> I do
> >   understand, what rocker can do for a heeled boat and that this
> rocker
> >   should be essential for a box-boat.
> >
> >
> >   But is there any experience, how much rocker must be minimum
> applied
> >   to get a box with low wetted area and good waterlines in the
> heeled
> >   condition, but which also can be made planning at moderate
> >   conditions.
> >   Ok, most fast boats (used not at the shore) are in planning
> condition
> >   max 5 % of the total sailing time, but I do not want to miss
> that in
> >   a
> >   box-boat of my own.
> >
> >
> >   I'm thinking about a design which is about 16 ft long, 4 ft
> wide, 2
> >   feet stern, 10 sqm, dagger board, conv. sails.
> >
> >
> >   My experiences are Lasers and many other fast and quick reacting
> >   boats
> >   of similar size, but I think, it should be possible to build a
> fast
> >   box design also, if not too wide. Retractable hiking boards of
> wood
> >   were tested from me some years ago on 2 very slender board-boats
> (3
> >   ft
> >   wide) and could be installed on a box-boat as well, to hold such
> a
> >   design in a more than 3 Bf wind. (Hiking board is like dagger
> board,
> >   but comes out at the top of the side.)
> >
> >
> >   Thanks for any experience or answer.
> >
> >
> >
> >
> >   Dieter
> >
> >
> >
> >
> >
> >
> >   Bolger rules!!!
> >   - no cursing, flaming, trolling, spamming, or flogging dead
> horses
> >   - stay on topic, stay on thread, punctuate, no 'Ed, thanks,
> Fred' posts
> >   - Pls add your comments at the TOP, SIGN your posts, and snip
> away
> >   - 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
> >
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> >
> >
> >
> > [Non-text portions of this message have been removed]
>
>
>
>
>
> Bolger rules!!!
> - no cursing, flaming, trolling, spamming, or flogging dead horses
> - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
> - Pls add your comments at the TOP, SIGN your posts, and snip away
> - 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
>
>
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Hi Dieter,

Im aware many owners have commented on PCB boats in that size range
planing: eg Gypsy, Surf, the scooners,and most commonly Windsprint.

However if the envelope is stretched a little, what about the
19'6"x20"(x 10'6" overall beam) Minimum Proa. It has to fly; maybe
change the rig to jib headed cat ketch ( 2 x 59sqft sprit boom? )
Perhaps , if you like, leave off the ama and have a hiking baord.

And what is going on with Anhinga? I've looked at those lines long
and hard: double ended for sailing and rowing, but with a slight
rocker in the forward third then dead flat aft. Like the long narrow
low powered planing designs,or the hulls of Fishcat, or Fast Brick?
Maybe not the beam in the quarter, but there's length.

Ideas anyone?

Regards
Graeme



--- Inbolger@yahoogroups.com, "John B. Trussell"
<John.Trussell@w...> wrote:

> Dieter--Welcome. In any user group, you must accept that much of

what is said is based on having read others' opinions and much of
what is stated as fact is likely to be opinion. This is a long way
of saying that I'm not totally certain, but I think....

>
> Flat bottomed boats need rocker if they are to operate at

displacement speeds, They should have little or no rocker if they
are intended to operate at planing speeds (but such boats will not
perform well at displacement speeds).

>
> A problem which flat bottomed boats have when they are moving

through the water and heeled is that the curve of the bottom and the
curve of the sides are diffferent. Therefore the water moves more
quickly over the side than over the bottom. This, in turn creates
drag inducing eddies at the chine.

>
> If I understand it correctly, Bolger has, in his "box boats",

attempted to match the curve of the bottom to the curve in the side,
thereby eliminating the eddies.

>
> If you wish to produce a fast "box boat", you might want to

consider building a wide, shallow boat which could be sailed at a
considerable angle of heel. The result would be similiar to sailing
scows and several scow shaped development classes--notably the
International Moth.

>
> Good luck.
>
> John T
> ----- Original Message -----
> From: dietermschulz
> To:bolger@yahoogroups.com
> Sent: Monday, October 04, 2004 11:35 AM
> Subject: [bolger] "Box-boat" rocker planning
>
>
>
> Hi, I'm new in this group, a rather experienced dinghy sailor,

living

> in Munich germany. My question:
>
>
> The typical box-boat designs of Philip C. Bolger without flare

of the

> sides, like June Bug(?), show a more or less remarkable rocker.

I do

> understand, what rocker can do for a heeled boat and that this

rocker

> should be essential for a box-boat.
>
>
> But is there any experience, how much rocker must be minimum

applied

> to get a box with low wetted area and good waterlines in the

heeled

> condition, but which also can be made planning at moderate
> conditions.
> Ok, most fast boats (used not at the shore) are in planning

condition

> max 5 % of the total sailing time, but I do not want to miss

that in

> a
> box-boat of my own.
>
>
> I'm thinking about a design which is about 16 ft long, 4 ft

wide, 2

> feet stern, 10 sqm, dagger board, conv. sails.
>
>
> My experiences are Lasers and many other fast and quick reacting
> boats
> of similar size, but I think, it should be possible to build a

fast

> box design also, if not too wide. Retractable hiking boards of

wood

> were tested from me some years ago on 2 very slender board-boats

(3

> ft
> wide) and could be installed on a box-boat as well, to hold such

a

> design in a more than 3 Bf wind. (Hiking board is like dagger

board,

> but comes out at the top of the side.)
>
>
> Thanks for any experience or answer.
>
>
>
>
> Dieter
>
>
>
>
>
>
> Bolger rules!!!
> - no cursing, flaming, trolling, spamming, or flogging dead

horses

> - stay on topic, stay on thread, punctuate, no 'Ed, thanks,

Fred' posts

> - Pls add your comments at the TOP, SIGN your posts, and snip

away

> - 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

>
>
> Yahoo! Groups Sponsor
> ADVERTISEMENT
>
>
>
>
>
> -------------------------------------------------------------------

-----------

> Yahoo! Groups Links
>
> a.. To visit your group on the web, go to:
>http://groups.yahoo.com/group/bolger/
>
> b.. To unsubscribe from this group, send an email to:
>bolger-unsubscribe@yahoogroups.com
>
> c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms

of Service.

>
>
>
> [Non-text portions of this message have been removed]

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

>
>
> I encourage you to look at the Gypsy. Owners on this site have said
> that she is as fast as a Laser. She is not a box boat, but I don't
> think she would be harder to build since the construction is taped
> seam.
>
> Peter

I seem to recall a photo somewhere - of Dan Segal in a GYPSY that was
close to "planing". That was in quotation marks as PCB's views on
planing are not the prevailing notion.

I found it interesting when comparing MICRO to LONG MICRO how MICRO
has a much more pronounced rocker, yet it closely follows the
curvature of the topsides. LONG MICRO rocker also matches closely
it's topside curve which of course is not as pronounced, since the
beam is identical. Both are in keeping with the designer's "seas of
peas" analogy.

MICRO with more rocker, has less wetted surface when sailed in
light air and upright. LONG MICRO has more wetted surface but is also
able to carry more sail and a taller mast as it has greater
displacement. So it all seems to work. LM hull speed will be somewhat
higher when heeling. (I notice where sailboat reviewers are measuring
speed to two decimal points now:-)

I was doing these comparisons regarding a cradle that might be used
for either boat and it will work. The cradle uprights just have to be
moved further apart for the LONG MICRO it looks like.

Cheers, Nels

> But is there any experience, how much rocker must be minimum

applied

> to get a box with low wetted area and good waterlines in the

heeled

> condition, but which also can be made planning at moderate
> conditions.

Hi,

The most important factor in planning is the power-to-weight ratio,
not the shape. If you can build the boat light and get enough sail
set, then fast speed will result. As for rocker, you might look at
the Bolger Light Scooner as an example. This has about the highest
performance among the well known Bolger boats, and will certainly
plane. If you compare it to the Sparkler design, you may find that
the shape is similar, but the Sparkler is not laid out for the crew
to sit on the side, and the rig is pretty small as a result.

I encourage you to look at the Gypsy. Owners on this site have said
that she is as fast as a Laser. She is not a box boat, but I don't
think she would be harder to build since the construction is taped
seam.

Peter

--- Inbolger@yahoogroups.com, "John B. Trussell"
<John.Trussell@w...> wrote:

You might consider studying, following or modifying the hull plan of
the Thomaston Galley. The boat PB drew to be a good rower, sail and
power boat.

Seems to me to be a good place to start.

Bruce Hector

--- Inbolger@yahoogroups.com, "John B. Trussell"
<John.Trussell@w...> wrote:

> If you wish to produce a fast "box boat", you might want to
>consider building a wide, shallow boat which could be sailed at a
>considerable angle of heel. The result would be similar to sailing
>scows and several scow shaped development classes--notably the
>International Moth.

Have a look also at the International Fireball, a fast, small,
planing sailing scow. It's not quite as simple as a Bolger box, but
it was designed originally for simple plywood construction. You'll
get an idea of its shape by seaching Google Images on Fireball hull.

Howard

Dieter--Welcome. In any user group, you must accept that much of what is said is based on having read others' opinions and much of what is stated as fact is likely to be opinion. This is a long way of saying that I'm not totally certain, but I think....

Flat bottomed boats need rocker if they are to operate at displacement speeds, They should have little or no rocker if they are intended to operate at planing speeds (but such boats will not perform well at displacement speeds).

A problem which flat bottomed boats have when they are moving through the water and heeled is that the curve of the bottom and the curve of the sides are diffferent. Therefore the water moves more quickly over the side than over the bottom. This, in turn creates drag inducing eddies at the chine.

If I understand it correctly, Bolger has, in his "box boats", attempted to match the curve of the bottom to the curve in the side, thereby eliminating the eddies.

If you wish to produce a fast "box boat", you might want to consider building a wide, shallow boat which could be sailed at a considerable angle of heel. The result would be similiar to sailing scows and several scow shaped development classes--notably the International Moth.

Good luck.

John T

----- Original Message -----
From: dietermschulz
To:bolger@yahoogroups.com
Sent: Monday, October 04, 2004 11:35 AM
Subject: [bolger] "Box-boat" rocker planning



Hi, I'm new in this group, a rather experienced dinghy sailor, living
in Munich germany. My question:


The typical box-boat designs of Philip C. Bolger without flare of the
sides, like June Bug(?), show a more or less remarkable rocker. I do
understand, what rocker can do for a heeled boat and that this rocker
should be essential for a box-boat.


But is there any experience, how much rocker must be minimum applied
to get a box with low wetted area and good waterlines in the heeled
condition, but which also can be made planning at moderate
conditions.
Ok, most fast boats (used not at the shore) are in planning condition
max 5 % of the total sailing time, but I do not want to miss that in
a
box-boat of my own.


I'm thinking about a design which is about 16 ft long, 4 ft wide, 2
feet stern, 10 sqm, dagger board, conv. sails.


My experiences are Lasers and many other fast and quick reacting
boats
of similar size, but I think, it should be possible to build a fast
box design also, if not too wide. Retractable hiking boards of wood
were tested from me some years ago on 2 very slender board-boats (3
ft
wide) and could be installed on a box-boat as well, to hold such a
design in a more than 3 Bf wind. (Hiking board is like dagger board,
but comes out at the top of the side.)


Thanks for any experience or answer.




Dieter






Bolger rules!!!
- no cursing, flaming, trolling, spamming, or flogging dead horses
- stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
- Pls add your comments at the TOP, SIGN your posts, and snip away
- 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


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[Non-text portions of this message have been removed]

Hi, I'm new in this group, a rather experienced dinghy sailor, living
in Munich germany. My question:


The typical box-boat designs of Philip C. Bolger without flare of the
sides, like June Bug(?), show a more or less remarkable rocker. I do
understand, what rocker can do for a heeled boat and that this rocker
should be essential for a box-boat.


But is there any experience, how much rocker must be minimum applied
to get a box with low wetted area and good waterlines in the heeled
condition, but which also can be made planning at moderate
conditions.
Ok, most fast boats (used not at the shore) are in planning condition
max 5 % of the total sailing time, but I do not want to miss that in
a
box-boat of my own.


I'm thinking about a design which is about 16 ft long, 4 ft wide, 2
feet stern, 10 sqm, dagger board, conv. sails.


My experiences are Lasers and many other fast and quick reacting
boats
of similar size, but I think, it should be possible to build a fast
box design also, if not too wide. Retractable hiking boards of wood
were tested from me some years ago on 2 very slender board-boats (3
ft
wide) and could be installed on a box-boat as well, to hold such a
design in a more than 3 Bf wind. (Hiking board is like dagger board,
but comes out at the top of the side.)


Thanks for any experience or answer.




Dieter