Re: IMB performance at Conroe
Hello Everyone,
I just looked at all the pictures of the Lake Conroe messabout. It
certainly looks like everbody was having a ton of fun. My standing
ovation goes out to all the boatbuilders. They've done a great job on
their boats!
I'd like to comment on the sailing of the IMB. I think that the
sail was poorly set and trimmed, as well. There appears to be no
downhaul, and the sail is not setting to its proper shape. This will
cause the boat to drag to leeward more than any other factor,
especially in light air.
The shape of the sail looks good, nice curves and it's smooth. A
good, hard yank on a downhaul would, in combination with the sheet
operating through the yard's long lever arm, have kept the luff from
sagging off. This threw too much draft, too far aft, into the sail.
Other refinements would be an outhaul on the boom to adjust the shape
of the lower part of the sail - loose in light air; progressively
tighter as it breezed up. This would be a cheap, uncomplicated
addition.
I've been goofing around with a balanced lug for a year or so.
Being a racing sailor (year round, here on the Chesapeake!) and a
former sailmaker, I'm a dedicated tweaker. I have added outhauls to
both the foot and head of the sail, so I can really bag it up in
ghosting weather, and then tighten everything up to flatten the sail
as the wind increases. I have rigged a cascading 6:1 downhaul on the
boom. This is worth its weight in gold. I can really strap it down,
keeping the luff tight in any wind.
I've also added a peak halyard to the rig. I'm of two minds about
it at this time. It's great for raising and lowering the sail. By
hauling on the regular and peak halyards at the same time, The yard
goes up and down horizontally. This is great when it's windy because
the yard doesn't flail around. It allows me to get a good crease
travelling from peak to tack, vital to a good setting sail. I use it
to fine-tune the shape of the sail.
The iffy thing about it is that, if I'm not careful, it allows the
luff to sag off because the yard can't act as a lever to tighten the
luff. If I tighten the peak halyard, I then have to tighten the
regular halyard, which then tensions the luff. If I don't do this,
the sail looks HORRIBLE, and my boat just digs a hole in the water.
Another experiment I'll try is a boom vang. The balanced lug
doesn't twist off much while reaching, but I still want to see what a
vanged sail will look like.
All these things make the rig more complicated to set up. Using
shackles and strops on the spars speeds the process. I think I use a
total of five small stainless screw-pin shackles, pretty cheap to
buy. The strops are just Dacron webbing or cast off super rope
(Spectra, Vectran, etc.) from friend's racing dinghies.
I think the balanced lug has a lot of possibilities for being a
high performance sail. It's certainly cheaper than the other high-
strung dinghy rigs. I can really stomp all over some friends' Snipes
and Comets in a broken down Surf I found covered by ivy in a
neighbor's back yard). These guys can outpoint me, but not by
much. I
beat them as much as they beat me. I'm designing an asymmetrical
spinnaker to set from the bowsprit end. I may end up driving this
boat under, this summer!
Anyway, This turned into a longer dissertation than I expected.
The IMB owner will get the hang of his rig through sailing it, and
making modifications to rigging and techniques as he goes along.
He's
got a nice boat, and the long cruising will allow him to get a lot of
intense experience with her.
Take care,
Pete Reynolds
I just looked at all the pictures of the Lake Conroe messabout. It
certainly looks like everbody was having a ton of fun. My standing
ovation goes out to all the boatbuilders. They've done a great job on
their boats!
I'd like to comment on the sailing of the IMB. I think that the
sail was poorly set and trimmed, as well. There appears to be no
downhaul, and the sail is not setting to its proper shape. This will
cause the boat to drag to leeward more than any other factor,
especially in light air.
The shape of the sail looks good, nice curves and it's smooth. A
good, hard yank on a downhaul would, in combination with the sheet
operating through the yard's long lever arm, have kept the luff from
sagging off. This threw too much draft, too far aft, into the sail.
Other refinements would be an outhaul on the boom to adjust the shape
of the lower part of the sail - loose in light air; progressively
tighter as it breezed up. This would be a cheap, uncomplicated
addition.
I've been goofing around with a balanced lug for a year or so.
Being a racing sailor (year round, here on the Chesapeake!) and a
former sailmaker, I'm a dedicated tweaker. I have added outhauls to
both the foot and head of the sail, so I can really bag it up in
ghosting weather, and then tighten everything up to flatten the sail
as the wind increases. I have rigged a cascading 6:1 downhaul on the
boom. This is worth its weight in gold. I can really strap it down,
keeping the luff tight in any wind.
I've also added a peak halyard to the rig. I'm of two minds about
it at this time. It's great for raising and lowering the sail. By
hauling on the regular and peak halyards at the same time, The yard
goes up and down horizontally. This is great when it's windy because
the yard doesn't flail around. It allows me to get a good crease
travelling from peak to tack, vital to a good setting sail. I use it
to fine-tune the shape of the sail.
The iffy thing about it is that, if I'm not careful, it allows the
luff to sag off because the yard can't act as a lever to tighten the
luff. If I tighten the peak halyard, I then have to tighten the
regular halyard, which then tensions the luff. If I don't do this,
the sail looks HORRIBLE, and my boat just digs a hole in the water.
Another experiment I'll try is a boom vang. The balanced lug
doesn't twist off much while reaching, but I still want to see what a
vanged sail will look like.
All these things make the rig more complicated to set up. Using
shackles and strops on the spars speeds the process. I think I use a
total of five small stainless screw-pin shackles, pretty cheap to
buy. The strops are just Dacron webbing or cast off super rope
(Spectra, Vectran, etc.) from friend's racing dinghies.
I think the balanced lug has a lot of possibilities for being a
high performance sail. It's certainly cheaper than the other high-
strung dinghy rigs. I can really stomp all over some friends' Snipes
and Comets in a broken down Surf I found covered by ivy in a
neighbor's back yard). These guys can outpoint me, but not by
much. I
beat them as much as they beat me. I'm designing an asymmetrical
spinnaker to set from the bowsprit end. I may end up driving this
boat under, this summer!
Anyway, This turned into a longer dissertation than I expected.
The IMB owner will get the hang of his rig through sailing it, and
making modifications to rigging and techniques as he goes along.
He's
got a nice boat, and the long cruising will allow him to get a lot of
intense experience with her.
Take care,
Pete Reynolds
--- Inbolger@egroups.com, shorty@s... wrote:
> > Michael Surface wrote:
> > David you got some great shots, looks like everyone had a great
time.
> >
> I tell ya, the nicest group of people on the planet!
>
>
> > I particularly enjoyed the pictures of the IMB, in that I am
> > considering
> > building it or one of its cousins (jewelbox, scram pram, or
> > petesboat), for use as a camp cruiser. It looked like it
performed
> > well.
> >
> I would talk with Jerry Scott (builder of the IMB) before you built
one.
> I really hate to sound like I am knocking a Michalak design, but
Jerry
> wasn't as happy as the pictures look. He was ready to torch the
boat at
> first, then thought about cutting off the mast and mounting an
engine,
> then resolved to sail it a little longer to have the boat show him
what
> it wanted.
>
> Jerry said it didn't feel right. I think that came from the radical
> design of sitting inside the boat. On one of his trips out, there
were
> 3 aboard and all of them were trying to sit on the outside. One on
the
> bow, and 2 poking out the back. With the weight up high like that
it
> would do all sorts of things to the stability that I don't have the
> technical terms for.
>
> Wil Gordon had owned a scram pram and he briefly mentioned that
people
> wanted to sit on the outside of that boat also.
>
>
> OK, for the positive things:
> Jerry mentioned he originally built this boat as a 3 day-to-2 week
> getaway solo camp cruiser. And, seeing it in person, this boat
looks
> like it would be great for that! 5' wide, just under 14' long (no
> registration needed in Texas), almost no draft, humongous cabin
space.
> I was so amazed at how much room there was on the inside. You could
> easily camp cruise in that boat like he was aiming for.
>
> When the rigging fell down, he got stuck in the shallows. He
probably
> would have easily avoided or been able to self rescue if he had the
oar
> ports that are on his todo list.
>
> Disclaimer:
> I don't like to speak for others, but Jerry doesn't have email, and
I
> spent a lot of time talking to him about his boat before and after
his
> maiden voyage. Bottom line is I think he will be very happy about
it
> after he gets used to it's unconventional design and exploits it
> distinct strengths.
>
> We talked about all sorts of little modifications and add-ons that
I can
> elaborate on-list or off-list if you would like. He has some really
> neat ideas.
>
> David Routh
> Shorty@S...
> Michael Surface wrote:I tell ya, the nicest group of people on the planet!
> David you got some great shots, looks like everyone had a great time.
>
> I particularly enjoyed the pictures of the IMB, in that I amI would talk with Jerry Scott (builder of the IMB) before you built one.
> considering
> building it or one of its cousins (jewelbox, scram pram, or
> petesboat), for use as a camp cruiser. It looked like it performed
> well.
>
I really hate to sound like I am knocking a Michalak design, but Jerry
wasn't as happy as the pictures look. He was ready to torch the boat at
first, then thought about cutting off the mast and mounting an engine,
then resolved to sail it a little longer to have the boat show him what
it wanted.
Jerry said it didn't feel right. I think that came from the radical
design of sitting inside the boat. On one of his trips out, there were
3 aboard and all of them were trying to sit on the outside. One on the
bow, and 2 poking out the back. With the weight up high like that it
would do all sorts of things to the stability that I don't have the
technical terms for.
Wil Gordon had owned a scram pram and he briefly mentioned that people
wanted to sit on the outside of that boat also.
OK, for the positive things:
Jerry mentioned he originally built this boat as a 3 day-to-2 week
getaway solo camp cruiser. And, seeing it in person, this boat looks
like it would be great for that! 5' wide, just under 14' long (no
registration needed in Texas), almost no draft, humongous cabin space.
I was so amazed at how much room there was on the inside. You could
easily camp cruise in that boat like he was aiming for.
When the rigging fell down, he got stuck in the shallows. He probably
would have easily avoided or been able to self rescue if he had the oar
ports that are on his todo list.
Disclaimer:
I don't like to speak for others, but Jerry doesn't have email, and I
spent a lot of time talking to him about his boat before and after his
maiden voyage. Bottom line is I think he will be very happy about it
after he gets used to it's unconventional design and exploits it
distinct strengths.
We talked about all sorts of little modifications and add-ons that I can
elaborate on-list or off-list if you would like. He has some really
neat ideas.
David Routh
Shorty@...