Inflatable fill it with expanding foam

[kieronriley]

Has anyone tried this , or know anyone who has. Somebody told me it works well( obviously on a knackered one?

 

[Plum]

Has anyone tried this , or know anyone who has. Somebody told me it works well( obviously on a knackered one?

Tried it on a fender once. Disaster. Impossible to know the exact amount to add and it will not fill/expand at a uniform rate resulting in severe distortion.

www.solocoastalsailing.co.uk

 

[AntarcticPilot]

It'll be very heavy. Expanding foam is a lot denser than air.

 

[prv]

Also don’t bother trying it with the single-part spray cans. I tried using a similar technique with an extra-heavy-duty plastic bag, thinking to fill it and form-in-place an odd-shaped packing block, but the foam just didn’t expand inside the bag.

Pete

 

[Bajansailor]

We also had this bright idea about 25 years ago, using 2 part pour foam in a fairly knackered Avon Redcrest.
It was not a success.
There were void spaces in so many areas, which then involved cutting holes locally to inject more pour foam.
And then these holes had to be properly patched.
And as AP noted above, it was heavy!
And the cost of the pour foam was fairly significant as well.

 

[john_morris_uk]

Single can foam eventually becomes waterlogged if immersed (according to the instructions on can I’ve got from Screwfix last week.) Any small leak and the heavy dinghy gets heavier and heavier…

 

[vyv_cox]

Single can foam eventually becomes waterlogged if immersed (according to the instructions on can I’ve got from Screwfix last week.) Any small leak and the heavy dinghy gets heavier and heavier…

Indeed it does. Years ago I built many kayaks for youth organisations and filled the ends with two-part supposedly closed cell PU buoyancy. A couple of years later we had to dig it all out, totally waterlogged.

 

[bitbaltic]

this is quite entertaining so I thought I'd have a bosh at google.

2.3m dinghy with 34 cm tubes = 0.83m3 per tube (very very roughly)
Density of foam 20 - 25kg/m3
2*0.83*20 = 33.2 kg
Packed weight of the 2.3m dinghy about 26kg

Foam filled tender then weighs something like 59 kg, carrying capacity obviously reduced by the weight of the foam

750 ml can yields 38 litres foam
1.66m3 = 1660 litres
1660/38 = 44 x 750ml cans of foam
7 quid a can = £308 worth of foam

New purchase price of 2.3m dinghy £349.95

So you can get a nearly 60kg, slowly waterlogging, knackered old dinghy out of this for only 88% of the price of a new one.

Bad idea!