Expanding isulation foam from screwfix for non-critical boating use.

[slawosz]

I think the best idea you had about this was to seek advice here rather than just going ahead with foam.

At least I am trying! There is old foamy place for battery, so I thought I can use a foam for boxes, but if its so much hassle I will find another way to keep them in place. I might end up with using OB1 and piece of softwood so they would have some support.

 

[Greenheart]

The battery on my Achilles was strapped to a flat wood platform, glassed into the bottom of the port-side cockpit locker.

I had sometimes worried that it wasn't likely to stay dry if the cockpit was deluged at sea, but after two years (including rain that found its way into various other hatches considered to be waterproof), the battery was never remotely damp...

...so I never changed it. I suppose the battery was best kept as level as the boat herself, but more importantly, it couldn't be allowed to move around. If I had kept the boat, I would have bought or constructed a secure battery box, mainly so I could use that locker for numerous other items that might be wet, or metal conductors.

I worked out that I could just fit my Tohatsu 3.5 short-shaft, (which definitely is long enough to drive the boat, through the well!) in the aft lazarette. The lazarette occupies the whole rearmost 4ft of the yacht, but is somehow less long than it appears - I couldn't fit the long-shaft Mariner 5hp in there...

...but I found a stiff plastic shelf (part of a collapsible garage shelving kit) and strapped semi-circular sections of pool-noodle to it. Pool-noodles are soft foam poles, used as swimming aids. The foam never seems to absorb water...

...the noodles spread the load and protected the hull from the sharp edges of the shelf, and the shelf made it possible to place (or drop) heavy objects like an outboard, into the rear lazarette without damaging the inside of the hull.

Important to understand that the Achilles 24 is a slender hull (7ft 1" beam) displacing 1,200kg, with no more volume below the waterline than Oliver Lee believed was necessary for performance. Headroom in the cabin is really low - 4ft 2" at best - so even to allow something approaching sitting headroom, there's minimal space under berths.

 

[oldharry]

DO NOT USE FOAM AEROSOL in enclosed spaces, particualrly a boat. The propellant is butane or propane based, and you will fill your boat full of gas. A friend working on an open boat filled it with gas from a foam aerosol, then blew himself up. Months in a hospital Burns unit, numerous 300 mile round trips for skin grafts and treatment at a specialist burns unit, and still six or seven years on not fully recovered. This stuff doesnt have the smell added to bottled gas, so it is virtually impossible to tell whether it is present.

Also very few of these foams are closed cell, which means they work like a sponge. It is impossible to dry the stuff out without digging it all out again. If you must use foam then get the Screwfix Fire proof stuff. Its closed cell and will not absorb water.

 

[Iliade]

Perhaps buy sheet foam and make a slot together structure.

 

[slawosz]

I visited my boat today and 12 lt container fits just about under bunks! I am very happy as it’s extends my storage space. I think I will simply use some timber as support.