Re: [bolger] IMB performance at Conroe
>From:shorty@...From what I have read from both Jim M and Phil B the birdwatcher design
>Reply-To:bolger@egroups.com
>To:bolger@...
>Subject: [bolger] IMB performance at Conroe
>Date: Wed, 26 Apr 2000 21:51:40 -0500
>
>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.
(which the IMB is an example) is designed for operation from inside the
enclosed cabin. The crew being low inside of the high sided cabin makes it
very stable. I have a feeling that this design concept would take some
getting use to.
>OK, for the positive things:This is what I have been thinking, as I look at these designs.
>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 >probablyThe original Bolger Birdwatcher had oars for auxiliary propulsion so it
>would have easily avoided or been able to self rescue if he >had the oar
>ports that are on his todo list.
seems that it would be reasonable to add them to the IMB.
>Disclaimer:I would really appreciate any information that you could give me on the
>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.
design.
Michael Surface
________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail athttp://www.hotmail.com
Interesting comments on IMB. Since I had been building one, they are of
particular interest.
I wasn't there, so take my comments with a grain of salt! But, looking at
Tim Webber's photos, the set of the sail looked to be pretty poor. My
experience with lug sails is they do best when the luff is *tight* and
straight. Jerry's looks like he rigged it the way Michalak suggests in the
plans without an effective downhaul. In one shot in particular, the luff
shows a deep sag to leeward. My first thought was they must have had a
terrible time getting her to point!
The best tweak I've found on a balanced lug is an easily adjusted, multipart
downhaul. With one , you can easily change sail shape to suit the
conditions. In strong winds, or for working to weather in more moderate
winds it is preferable to set the downhaul up tight, flattening the sail and
minimizing twist.In lighter winds and downwind in more moderate conditions,
loosen the downhaul to put a little more draft in the sail to keep it
powered up.
On my old Windsprint, I wound up experimenting with halyard and downhaul
locations to improve her balance. Moving the sail a little forward or aft
would make a big difference in pointing ability. Raking the mast would have
accomplished much the same things. If IMB won't balance, play with the mast
rake. As designed, it should be easy to adjust.
I sent Tim Webber a scanned drawing of my way to make an easily adjusted
downhaul. I'd invite him to post them to the vault if anyone is interested.
One thing that always concerned me about these Birdwatcher cabined boats was
the helmsman's lack of "feel" for the wind. I'll bet a masthead Windex would
be of great use in substituting the feel for the wind.
JB
particular interest.
I wasn't there, so take my comments with a grain of salt! But, looking at
Tim Webber's photos, the set of the sail looked to be pretty poor. My
experience with lug sails is they do best when the luff is *tight* and
straight. Jerry's looks like he rigged it the way Michalak suggests in the
plans without an effective downhaul. In one shot in particular, the luff
shows a deep sag to leeward. My first thought was they must have had a
terrible time getting her to point!
The best tweak I've found on a balanced lug is an easily adjusted, multipart
downhaul. With one , you can easily change sail shape to suit the
conditions. In strong winds, or for working to weather in more moderate
winds it is preferable to set the downhaul up tight, flattening the sail and
minimizing twist.In lighter winds and downwind in more moderate conditions,
loosen the downhaul to put a little more draft in the sail to keep it
powered up.
On my old Windsprint, I wound up experimenting with halyard and downhaul
locations to improve her balance. Moving the sail a little forward or aft
would make a big difference in pointing ability. Raking the mast would have
accomplished much the same things. If IMB won't balance, play with the mast
rake. As designed, it should be easy to adjust.
I sent Tim Webber a scanned drawing of my way to make an easily adjusted
downhaul. I'd invite him to post them to the vault if anyone is interested.
One thing that always concerned me about these Birdwatcher cabined boats was
the helmsman's lack of "feel" for the wind. I'll bet a masthead Windex would
be of great use in substituting the feel for the wind.
JB
----- Original Message -----
From: <shorty@...>
To: <bolger@...>
Sent: Wednesday, April 26, 2000 10:51 PM
Subject: [bolger] IMB performance at Conroe
> > 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@...
>
>
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