Mbuli
Two letters from Craig O'Donnell

Tuesday, February 13, 2001 11:24 AM

Hi Chuck.

Random Proa Thoughts

Attached are a couple shots of John Harris' proa, Mbuli (he says it's Swahili for "foolish").  Launched last Sunday, 11th. We got in about a 45-minute sail with only one knockover, and that we think could have been prevented. With the help of the chase boats we got 'er righted.  Water was about 38 degrees so we had all sorts of waterproof stuff on.
Brrr. Cold hands but otherwise OK after our dunking.

proa6.jpg (12617 bytes)John said (I didn't see the action as I was too busy falling over) that the sheet he'd selected was too fat for the boom blocks and jammed when he released the sheet when we got a big puff... he was trying to head up and accelerate the boat, the ama lifted, and then the sheet would not release the foresail boom. In theory we should have come back down on releasing the foresail.

We did reach and run and head up successfully and easily, and the shunt, while slow due to inexperience with all the steps to take, was simple enough.

Actually, aside from working out kinks, the boat sails very, very nicely and this is what they call "shakedown cruising". A capsize beats sinking to the continental shelf in your new submarine!

proa1.jpg (21824 bytes)The wingmasts are 99.9 percent sealed - only the halyard block opening at the masthead - and they make great outriggers so the boat floated way high and dry. John was joking that they have more buoyancy than many catamarans but at 24 feet long with a big airfoil section added he's about right. The problem was that we simply weren't sure what the best recovery technique is and two guys leaning backwards while standing on the chine isn't enough. We had the chase boat guys lift the mastheads up while we leaned back and that did it.

John has a short list of things to fix, some are probably long-range rather than "fix for the event in March" -- for example we're agreed that the ama is currently a little too much on the minimal side. It doesn't sink, but it's not conducive to a comfortable ride: too low, too wet. There's a "theoretical approach" that seems right and then you discover the practical issues by testing. I guess that's what makes boats fun.

proa2.jpg (14617 bytes)This is a very light boat (two people can pick up the main hull and carry it). Aside from stepping the masts, which are also experimental,the boat goes together easily and the most tedious part is lacing up the trampoline. We're working on that.

I could see a version built from plans with a couple aluminum pipe masts, sealed with plugs so they float, sprit-boomed sails, masts rotating in the tabernacles, being very, very easy to set up and rig - otherwise identical - and very nearly a cartopper boat. The main hull would need a small trailer but only for transport, not for launching.   Everything else goes on cartop racks.

proa3.jpg (18765 bytes)It's probably over-rigged for winter Chesapeake winds, but in a 5kt breeze summertime on the Chesapeake you'll actually go somewhere and that's what the design brief is all about. Our next outing will involve sailing with reefs <chuckle>.

John is busy working out some rigging tweaks and I'm making growling noises about the ergonomics of trampolines on cruising boats, but the gist is that we'll take it down to the Watertribe Challenge around Mar 2nd and go from Tampa to Key Largo.  I'm sure there will be some reportage after the race/regatta ends. We're not really in it as a race, more like a cruise/test flight/whatever but making time would be real nice <grin>.

Craig
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Friday, February 16, 2001 5:41 PM

Those who get WoodenBoat will have seen the take on a Bolger "cartoon proa" by a fella in Florida name of Norwood. I've tried to get more info from him without much success, but at least something akin to Bolger's cartoon has been built. This includes the wacky triangular sail, which no one has been able to have work -- I know personally of three experimenters who could not control the sail.

proa4.jpg (12051 bytes)On another Bolgeresque proa: John Harris and I took his 20-footer to Tampa Bay for the Watertribe race, got off the beach in 20-knot winds running south under bare poles. We averaged about 5-6 knots with a few bursts of 8-9. The waves can best be described as "boisterous" and around 6 feet.

Bare poles in John's case means 48 sq. ft of wingmasts.

proa7.jpg (17531 bytes)We had planned an outside transit down Fla's west coast, skirting the beaches, but with 20 kts and up to 10 ft waves outside we decided to go through the bays and sounds. Unfortunately we mistook a navigational marker at the south end of Tampa Bay and ran upon a sandbar, bending one rudder shaft. This mistake is understandable given the rough ride and poor visibility, and in normal winds it would have not damaged the rudder and would have been a moment or two of shoving to get the boat over the shallows. It's designed to sail on the Chesapeake in summertime, after all, where the water is shallow and the winds are about 7mph average.

After putting the "good" rudder in place we set off again looking for a place to land to assess the damage better and promptly ran onto ANOTHER sandbar, bending the other rudder.

So we got the boat off that, and sailed to a nearby beach using paddles to steer.

After another series of amusing mishaps including capsizing in 2 inches of water, we retired from the race and went on down the coast in support of Kevin O'Neill who was sailing a CLC SailRig Mark II.

proa5.jpg (12673 bytes)Kevin also suffered from the rough conditions though his boat (a Chesapeake 17) and rig did not. He got salt-water blisters on his hands and also dropped out.

So the short story is that the proa John designed works quite well and was an exciting but not scary ride in conditions which were very much outside it's "design envelope". We're disappointed that the winds were so nasty, but it is unusual in Florida for March and of course you cannot pick the weather. If it looked as if the high winds were one-day and expected to calm we would have waited, but as it turned out the forecast was for 2-1/2 days of wind; reality showed that winds were still higher than normal for 3+ days.

And so it goes.

However if you look at the photos of John's proa "Mbuli" you will see that the lower hull owes much to Bolger (flat, rockered, some flare) and the upper hull owes much to the Birdwatcher cabin style.

--
    Craig O'Donnell
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 _________________________________

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        Friend of Wanda the Wonder Cat, 1991-1997.

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