How many forum members does it take to design an offshore trailable multihull?

Richard Woods has become a bean counter! But you forgot to tally the people who read the forum but didn't chip in which is much safer! The world will know it can trust his design calculations with such an eye for detail

 

Yes! That is one thing that has to be covered! Calculations! Beam strength calculations, heeling moment calculations, sail area calculations, hull resistance calculations, chic magnet calculations, and over budget in the poor house calculations.

 

Is Raps playing Taps for a big project? Budget boat ownership demands one be a bean counter too.....Reading over my Hedley Nicol instructions he listed an advantage of double diagonal cold molding I hadn't thought about which was the working guy could buy a few sheets of ply at a time to keep building. Not as economical on materials but a good idea on the time end. If you work X years to buy all your materials at once you then have to start the build which has been put off X years and will now take Y years to complete, plus you must fight the temptation to do something rational with the money like leave the poor house!

 

playing taps for a big project would require common sense I was originally thinking of keeping the laser 28 and building a budget trimaran... with money I wouldn't be crying over if it didn't work out... as for my time... my time has value only if I am making money... free time is just that... free... if i spend my time working for myself, I am making money! Unless I'm working on something that will cost me more money than I'm paying myself, then it's called a hobby. Hobbies are ok as long as you can afford them, in this light hobbies are like marriage. My wife's hobby is being frugal, which only becomes a hobby when she is working me to save more, retire early, and sail on a boat made out of cardboard boxes and sports polytarp sails. She actually encourages me in my boat building flights of foolish fancy, mostly because I have an awesome life insurance plan now that I race long distance solo races on lake Michigan. I was in a squal last year alone in my laser 28.... 47 knots of wind... with a full main and storm jib, under autopilot. That is the difference between an offshore racer and a sport boat. I wanna race multihulls... which my default makes me nuts.... so doing something rational with my money is out of the question. The question now becomes, If I sell my Laser 28, and use the thousands I spend a year on various marina expenses (slip, crane...ect) on a trailer sailor, I'll still be able to race now, retire earlier, and build that big wharram and cruise to figi while I still have teeth! But, apparently, everyone's definition of trailerable includes a 1 hour set up and two people... that isn't a trailer sailor, that is a 1 way ticket to yearly slip fees... which are now more a month than my first mortgage. why is it so freaking hard to design a fast set up trailer launcher, spartan weekender that is a screamer to boot? seriously... we put a man on the moon, we split the atom, we put holes in swiss cheese! what is so freaking hard about this people! I don't have an hour to set up a boat every time I wanna sail... if that is how it has to be I'll give up sailing and spend time with my wife! that's like digging a tunnel out of a POW camp in order to escape only to emerge on the other side right in the middle of a minefield...

 

Set a max beam of 8 feet, skip the mast and go right to a parasail, light air days use the polytarp for shade while you drift with the zephers and read a good book. You might be single if the wife reads the forum so work on your dating skills. For instance friends tell me I'd do better if my idea of a hot date didn't include scrubbing the anti-fouling. My attempts at selling sanding as foreplay haven't gotten many results either though I have been referred to as coarse but not extra fine

 

Wise advice cav! wise advice indeed.

 

This is the holy grail of small multi design, which no one has achieved, so evidently it is "freaking hard", but only if you want a multi that looks like everyone else's.
Try this:
35' long, 800 lbs, sail area 514 sq' (Bruce number 2.4) to meet your "screamer" requirement.
20' beam to keep you safe in strong winds. 6' 6" beam on the trailer for easy towing.
Unstayed schooner rig with relatively small sails and no extras to minimise the replacement cost of sails and rigging, makes it very simple to sail solo and to balance the boat.
Sails and booms are permanently mounted on the boat. Masts are raised by gin pole which takes less time than untangling the stays on a conventionally rigged and raised trailer sailer mast. Double hinged beams locked with 4 tapered pins are not as elegant as F boats, but are much cheaper and just as quick. Launching and recovery times will be much less than 1 hour, solo.

Hulls and beams are built from flat panels, either ply/timber (heavier) or glass/foam. Dory hulls (possible as it is long and light) with all panels self aligning (no strongback or build frames) and very few additional fittings (no chainplates, travellers, tracks, daggerboards, jib or spinnaker gear) make it a very quick, cheap ($16,000 materials to get it to sailing stage) and easy build. The carbon masts will last forever and can be self built ($700 materials per mast). The trailer is a single axle flat bed so is much cheaper than for a cat or tri.

The down side? It is a harryproa, so it looks different. That is the price you will pay to meet all your requirements. http://au.groups.yahoo.com/group/harryproa/files/Wooden Boat Competition/Rob/

rob

 

Rob Denney, nice proa but, as you said, not everyone likes their look.
So why not get rid of sails, make a super-simple foldable catamaran with just two hulls, two beams, the net, two rudders and a forward-beam-mounted hinge for... a kite.
No masts, no sails, heeling moment reduced to a minimum, and much more power available for fun. And the kite, once folded, occupies 1/10 of the space occupied by sails and masts.
Hmmm... Ah right, not everyone likes kites either.
Cheers

 

LOL!

No need to go for a such a "complex" thing like an offshore trailerable multihull... Just look how many forum members it takes to design a shoal-draft aluminum jon boat. There's a thread somewhere around...

 

Oooops, it exists - kind of. Both in smaller, single-person version:
http://www.youtube.com/watch?v=f1KQsWDGOI8&feature=player_embedded

in amphibious version:
http://www.youtube.com/watch?v=xc3odmupoT8&NR=1

Wanna see how it looks from the kite's point of view? This is fun:
http://vimeo.com/25390468

Cheers

 

Darn it, I meant kite/parasail.....really does make sense to lose the mast and lower the CE reducing beam requiremenrts. Might be faster for less money?sail inventory too in many conditions. Watched the video and like how the kite sail lifts the boat through the waves.

 

Richard,

After 25 pages of "edgy boat design" it was a relief to get it all done in one post.

I probably accounted for at least 10 of those lines.

I actually am inspired to be more civil in the future, hope I can keep that vow till the new year, at least.

Everyone is enouraged to remind me.

Talk about drift, I had not read past the first 5 posts when I wrote this. Another mistake I keep making.

Marc

 

True, and with good reason as they are still not developed enough for general purpose boating, unlike proas, which are. Will not be long though.

I have been playing with kites on boats for a while. The biggest so far is a 420 sq m/4,515 sq' job which we took in the Sydney Hobart a few years ago. I arrived on the boat (80;ter( with the kite the day before the race. The rest of the crew were very sceptical. Once outside the heads there was almost enough breeze to fly it, the owner had booked a chopper to take pics so up it had to go. Got it flying, but with a bunch of neophytes it was just a matter of time till it swam. When it did, it went back in the bag and the breeze and was not used again.

A couple of years before that, we had flown it successfully on a 66'ter http://www.kiteship.com/photoview.php?show=aaptkite1.jpg and a 56'ter, although the latter was helicopter assisted.

rob

 

Rob, you da man !

 

Tra la la laaaa la !

You guys didn't wait six months before bringing the old thread to life !