Rob,
Your designs are always so much prettier than mine. Now I am not sure if I can even post my WBC entry <sigh>.
That pricing is pretty amazing. I am particularly curious about the removable bows, because I am, as you know, "Mr fit-it-in-a-container" <grin>
Just to try to get the pricing in perspective, is that $35K for the hull, rig and rudders probably about half the price of the finished boat? It sounds like the mast, boom and sails will be another $25K at least (more? telescoping wing mast?). Then add outfitting (outboard, electric, instruments, etc) $5K and painting ($5k?). Has the whole price been quoted? Maybe $75K + shipping ($6K) ?
Do you have a sense of which would be more expensive: a single 2 part 60' mast, or a schooner rig with 2 40' masts, which requires less structure in the leeward hull. It would seem the performance is probably about the same either way (or at least close enough for me).
- Gardner
On Tue, May 10, 2011 at 8:12 PM, Rob Denney
<harryproa@gmail.com> wrote:
Doug,
Not sure about the ultimate skinniness. There are two pluses of long and skinny. One is top speed, the other is resistance to nose diving and pitching. How skinny is too skinny depends on the weight to be carried and the engineering complexity. Suggest you start with a calculation of the final weight of the boat, then the best length for handling, marina, build space etc and design around that. Your lee hull requirements are correct. Also needs to get the beams clear of the water, and on some boats have storage/sleeping space.
The Team Phillips bow falling off was primarily a built fault, secondly a structural design fault. That length of hull overhang is not impossible.
Taper to the bows starts at the beams, or the rudders on single beam boats.
El could be finer if sailed solo, but was designed for two people and two rigs. Incidentally, I am going to build a telescoping wing mast rig for my El in the next month or so, and Steinar in Norway has a very cunning plan for a telescoping wing rig for his El, which he wants to build in the near future.
Bow height is determined by doubling the submergeddepth of the bow at which the stern raises from the water in a nose dive. Could easily be less if the crew knew what they were doing or the boat was long compared to the rig height.
I try very hard not to have weakest links in the design or build stages! Ideally, the crew is the weakest link and the boat will look after them when they screw up.
There are three Solitarrys so far. First was the KSS demo boat, which is being completed in NSW. Second is mine which was the first "flat panel, fold it up with no cuts and shuts" boat. The hulls and beam are finished for this, but the lee hull and beam are for sale now that I have seen what can be done on #3. The third is professionally built, using the same technique but with more curves than mine. The lee hull is ready to join (can't proceed further until the mast is built) and the ww hull is ready for it's deck and cockpit seats to be infused, hopefully next week. This boat is a fixed price ($35,000) for the hulls, beams and rudders, all installed and ready to paint. It has the same ww hull as my Sol, but a much better looking lee hull, with removable ends for shipping. There will be pictures available when the beams are complete.
Ben,
Thanks. Haven't drawn the pantograph but it is pretty easy. The lee end rotates around the mast (same idea as the ballestron boom), the ww end in a slot in or on the hull. Small problem is the trampoline, which would be loose when canted. Another is that, as pitching resistance increases, heeling resistance goes down, which is significant on an apparent wind boat. To make up for this, the beam overall would be higher than normal. I think a longer lee hull has the same effect as pantographing, with higher top speed and less hassle, but would love to be involved in a project to prove me wrong.
Carlos,
No expectations of the judges, although if they only judge by their stated criteria (fast, seaworthy, simple, trailerable, easily rigged and launched, less than 12m on the trailer, portapotti, overnight accommodation, able to go upwind in 40 knots: see http://www.woodenboat.com/wbmag/designchallenge3.php), I cannot think of a boat type which fits them better, and Expeditionarry should win both the composite and wooden boat prizes ;-).
I suspect the results will be similar to the Norwegian Multihull Club design competition, where a harry got runner up to a conventional tri whose only distinguishing feature was that it was shorter than the maximum in a futile (as proved by the first and only one built) attempt to match the cost criteria. If I get an honorary mention, I will be happy.
Regards,
Rob
On Tue, May 10, 2011 at 6:46 PM, Doug Haines
<doha720@yahoo.co.uk> wrote:
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Hi Rob,
How skinny is it no longer any better?
I mean, how does it help to go any more skinny?
I think Sidecar is 800mm wide - leeward hull.
What is the requirements of the lw hull?
Buoyant enough to hold the whole boat without depressing under to much.
Wide enough to take any torsion or wave stresses. Handle the mast and beams and other loads.
If say for example on Solitarry, what would be your weakest link or are younot really totally sure about what could be under-engineered?
Again the phillips catamaran accident is what you would hopefully avoid.
With your long 16m length it will not immerse much even aflying.
Does the taper down in height towards the bowas start at about the rudder position?
What are the comparisond to the Elementarry racer? I know it is about twice the length, but what about the other dimensions?
If you've doubled the length, but narrowed the width to 75% of elementarry, that is pretty radical.
Could Elementarry racers then be built way lighter too?
Doug
On Tue, May 10, 2011 at 10:09 AM, Doug Haines <doha720@yahoo.co.uk> wrote:
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And I always wonder about the couple distance.
I mean the beam to hull "bury".
But, you can simply add on to the hull at that point.
How skinny is Sol leeward hull?
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600mm/2' wide which is an engineering challenge, but looks very slippery.
rob
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