unsinkable yacht?

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tdsail

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hi all, as part of my many things to prepare my yacht to be ready for offshore passage, I am considering making her unsinkable. So I am thinking of purchasing polyurethane expanding foam (from somewher like Wickes) and I'm wondering if anyone has experience with this and roughly how much would I need to make a 2.5t 24' yacht positively buoyant...
 
If you want to displace about three tons of water, you'll need three cubic metres, which might leave you somewhere to sit.
 
hmm...thats not so bad...shes got plenty of storage...what about the material from the likes of wickes or screw fix...is it appropriate?
 
Short answer. You need 3000 1-litre bottles of drinking water.You may wish to commence your trip with drinking water in <some>of those.

If you are serious have a google at some known unsinkable boats, Etap and Sadler 32 and 34 come to mind. It is quite useful to be able to partition off parts of the hull where you may expect a breech and to consider various ways of repairing same well enough to keep the sea out and continue sailing.
I am all for self sufficiency and meticulous preparation, good luck.
 
[ QUOTE ]
hmm...thats not so bad...shes got plenty of storage...what about the material from the likes of wickes or screw fix...is it appropriate?

[/ QUOTE ]

Not really, it tends to form open cell foam rather than closed cells. ie: it absorbs water to some extent. It will slow down water ingress for a while but ultimately the wreck will sink. In addition it will make finding the hole impossible and doing any work on the hull just difficult too.

The foam expands significantly before setting, may split all the furniture before it sets.

The boat may be unsaleable afterwards.

If you fill all the storage where are you going to store the beer?

If you are that worried about sinking then I suggest you stay ashore, its a rare event in reality.
 
Years ago many people, including me, built kayaks and filled the ends with expanded polyurethane foam for buoyancy. A year or two later we all had to dig the foam out again when it became waterlogged. The kind of foam you can buy from various suppliers, the two-pack stuff, not aerosols from DIY stores, is not completely closed-cell and it will absorb water over time. Admittedly a yacht does not suffer the same immersion that a kayak does but the foam would tend to soak up from the bilges. The kind of foam in Sadlers 26, 29 and 34, the 'unsinkable' ones, is virtually 100% closed cell and in general cannot be used by amateurs.

There are possibilities for airbags in a yacht but is the expense and maintenance of any positive buoyancy system worth it? How many boats sink on offshore passages?
 
the obvious question is - why? How often do you hear of a boat sinking? Why do you think that somewhere between 98 and 100% of all boats are not unsinkable types? Why is did people drown from their liferafts in the Fastnet disaster when their boats were subsequently found afloat?

By all means pay attention to keeping your boat watertight, and to having good kit to call for help. But I reckon unsinkability is way down the list of things to spend money on. Maybe on a par with on board hi fi?
 
My biggest worry on long passages is hitting something like a part submerged container and bashing a hole in the bow. Flotation bags, bottles or foam will lose you a lot of space. You may be better employed in creating a watertight compartment forward that may keep you afloat or buy time to get off a distress call and get help. I have seen one IOm production boat that was modified by beefing up the bulkhead to the forepeak and fitting a robust door with a circumference seal and proper clips top and bottom. You might be interested to have a look at the You Tube video of the Dehler boat collision testing , just to see how much punishment a GRP boat can take. Or, you could buy a steel boat!
 
Re: Have a look at how Sadler and Etap do it

Sorry to be an anorak, but only the Sadler 26 and 34 were unsinkable. The 25 and 32 were earlier boats.
 
Re: Have a look at how Sadler and Etap do it

It might be a good idea to fit explosive bolts to the keel. Getting rid of the lump would mean you had less weight so needed less bouyancy.

Daaaaaaad, what's this button for? ..........

DON'T !.....

Bang!

/forums/images/graemlins/laugh.gif
 
Re: Have a look at how Sadler and Etap do it

[ QUOTE ]
It might be a good idea to fit explosive bolts to the keel. Getting rid of the lump would mean you had less weight so needed less bouyancy.

Daaaaaaad, what's this button for? ..........

DON'T !.....

Bang!

/forums/images/graemlins/laugh.gif

[/ QUOTE ]

See, Bavaria are well ahead of their time. /forums/images/graemlins/wink.gif
 
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