Historical multihulls

After four years of sailing on two different Trimarans, I got fed up with foam of any kind for floatation, for reasons already stated.
I considered ping pong balls
But realised after two secs consideration that in the event of a ruptured hull, however small the rupture, the ping pong balls would become escape artists.
I then considered milk jugs but they would not be much better unless locked in foam, and that would be a really messy job.
Finally, in my Bucc 24, I used 4 gall Acid bags, which can be crushed up and inserted in the spaces between the frames in the Amas, inflated with a vacuum cleaner in reverse, allowing the pressure to equalise before screwing on the caps. This provided enough flotation so that even if all the hulls were ruptured, the soft and ply-able bags would not float away or be damaged, but would support the whole boat sufficiently to perhaps reach safety. Fortunately I never had a situation where I had to test this theory.

 

Or the cockatoos peck it to 'death'.....

But you don't have that problem in the US of A...lol

But yeah, polystyrene needs to be encapsulated to prevent UV damage.

Seems like everyone's agreeing on this, then?

 

Buzz. I think you have got it wrong. The plastic acid bags are INSIDE the ama hulls, in between the Frames---- not Beams.

 

OS7
Don't see what I'm getting "wrong" - I never criticised your acid bags solution..??

OK, so you'd rather use bags than foam. Personal choice. YMMV

Frankly, if the hull split, I reckon the bags would get pinched and leak, and if they weren't prevented from moving at all, they'd eventually chafe through, but that's only my 'opiniion'.

But I would not use bags or bottles for that reason. Foam is a bugger to get right, but is the superior solution, I believe.

 

Thanks, it's an '86 Irens F40, built by JTA in France, ex "GAJ Neptune".

 

Steve Dashew put up a new post to supplement his excellent post on Catamaran History the Early Days with more photos.

http://setsail.com/catamaran-history-early-days-updated/

and also a posting on Beowulf IV and C class development.

http://setsail.com/beowulf-iv-and-the-early-c-cat-foil-development/

 

I don't know where people get the idea that polystyrene foam just falls apart, it does not IN REAL LIFE, as in, packed tightly in the same places as are typically used for air tanks. In the Mac 36 for example the entire ends of both hulls are filled all the way up to the deck ahead of the fore beam and aft of the aft beam and under all 4 berths. At the most the corners get rounded over a little, they are packed in tight and don't move, also obviously UV is another non issue. In fact polystyrene stands up quite well to UV anyway unlike polyurethane foam. As I said, they use it, unprotected, to support the outer end of floating docks here on the lakes here, it comes in big blocks about 8ftx 2ftx 2ft or thereabouts, called dock billets, it is exposed to the sun at the sides, holds up for years.

 

Polystyrene does dissolve in styrene - no surprise there! so is badly attacked by uncured polyester resin and also petrol/gas

The important thing here is differentiating between a foam block that is, for example, used to keep a Laser dinghy afloat if you leave the bung out and buoyancy that has to keep the hull afloat after a catastrophic hull failure.

The latter is much harder to achieve. For example, will your deck hatches be strong enough to hold up the boat? or will they burst off? Will the blocks simply slide to one end and make the boat float bow up/down (but still be untenable for the crew)

You also have to consider what you want buoyancy for. Is it to save the boat, or to save the crew as well? Under the old USCG rules the buoyancy requirement was only enough to save the boat - good news for insurers, less good for families.

This is now way off topic, I suggest people start a new thread to discuss buoyancy, a thread that I could contribute to but I won't do it here.

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

Old shot of Supplejack blocked up for cleaning and probably minor repairs, 1979; we would run ashore from near Watchman's Island to the sand and shell on Home Beach, no sail, just the mast. The sloping skeg rudders were a bad mistake and were changed to lifting, vertical ones with no skeg. Check out the catenary curve to the trailing mast edge. In those days the beach was little used, bit different now.

 

Project Ppalu's repair is making progress:

https://www.facebook.com/media/set/?set=a.275513669276881.1073741867.170355479792701&type=1

 

^^

I remember being impressed in Kiel by a big Spronk that was in the first Round Europe Race (85?), I think it was called Spirit of St Kitts. It had a beautiful pastel paint job and a large, very comfortable-looking center cabin arrangement (deep in a box somewhere I have photos of it).

 

The mighty Orange II maxi catamaran one time holder of the Jules Verne record is set to be transformed into a very fast world cruiser.

http://www.multiplast.eu/fr/actuali...deuxième-vie-pour-le-catamaran-orange-ii.html

 

An interview with Jean-Marie Buignet of the specialist composites firm C3 Technologies on Voiles et Voiliers.

http://www.voilesetvoiliers.com/cha...buignet-notre-rayonnement-vient-de-la-course/

 

Wow, just think of the distances you could cross FAST in that beast and no problem outrunning storms too!

 

What a wonderful way to ensure the survival of one of the most advanced Catamarans of it's day.