ziacek
New member
yes, here is something: http://www.turtlepac.com/products/underwater-lift-bags-a-yacht-floatation.html
making a boat unsinkable.
- Thread starter chrishelen
- Start date
yes, here is something: http://www.turtlepac.com/products/underwater-lift-bags-a-yacht-floatation.html
Sans Bateau
Well-known member
There is an easy solution to this.
Searush
New member
OP talks about unscrewing the deck to release pressure & his intention to fill the under deck space - is he talking of an open dinghy style boat? Cos most of his respondents seem to be assuming a big heavy cruiser.
turning a dinghy upside down & pouring the mixed foam under the side decks could be quite effective, although it would be more effective if lower down. Poly foam is commonly used in home made GRP kayaks, with the usual caveat of not too much at a time to avoid splitting the seams.
turning a dinghy upside down & pouring the mixed foam under the side decks could be quite effective, although it would be more effective if lower down. Poly foam is commonly used in home made GRP kayaks, with the usual caveat of not too much at a time to avoid splitting the seams.
chrishelen
N/A
Aussie land, ffs.
daveyw
Active member
Umm, everytime you finish a plastic bottle of coke, wash it out, screw the top on and stow it in the space you're want to use for bouyancy. The big 2l bottles are best. Thats only 2500 bottles you need!
Rigger Mortice
N/A
He needs 2.5 cubic metres so it's fair to assume that it's more than a open dinghy.
I'm not convinced that there is a lot of point in adding foam in the hope that there is much to be gained if a boat is made to be unsinkable. The Rafikiki was still afloat...after a fashion...several days after she lost her keel. She may still be bobbing about out there.
john_morris_uk
Well-known member
Well that's totally confused me. What sort of a boat are we talking about? I have been involved in getting boats coded and although the requirements talk about weatherproof decks of suitable construction etc, I don't remember any requirements for non sinkability in offshore sailing yachts. In fact it isn't until you get to Cat 0 (Ocean going) that you even need watertight bulkheads.
RAI
Well-known member
Why not seal up the available spare compartments, maybe add a waterproof inspection hatch, so the volume could have dual use.
shan
Well-known member
So much misinformation about PU foam on here. Firstly, there are several different types of PU foam. Some are single component open celled,others are 2 component open cell, some are 2 component closed cell. Some react to moisture and continue to expand over 24 hours, others react when the 2 components are mixed and will continue to expand over a period differing from approximately 20 seconds for a quick expanding formula to several minutes for a very slow formulated expansion (yes, this is a slow expansion for a 2 component closed cell). Those that react without the addition of moisture should never have moisture added to them, as you then change the formulation qualities and end up with a badly reacted foam with an enormous amount of broken cells. Some formulations are designed to be sprayed, or injected or mixed and then poured. Various formulas have different levels of rigidity, density and tensile strength.
Rigger Mortice
N/A
Is this for some type of working boat?
JumbleDuck
Well-known member
As I understand it, it's addition of water to the polyol component that gives you foam rather than solid PU.
shan
Well-known member
Water acts pretty much as a blowing agent.
shan
Well-known member
To add to this, you will find there is a very small percentage of water added to rigid and semi rigid formulations as you will end up with a large inital expansion and then shrinkage.
chris dyer
New member
I have the same thoughts. I'm thinking that I'm going to make all my storage areas air/water tight with sealed hatches. I'm also going to take my time and 'air tight' all the areas between the outer hull and the inner fibreglass lining. Above the fibreglass lining I'm going to epoxy 40mm sheets of extruded (not expanded) polystyrene sheet as accurately as possible and coat it with a 100gms glass (epoxied). This will provide bouyancy and excellent insulation. In the deadly Fastnet many of the boats that were abandoned survived the storm. People were dying in liferafts when they may have survived on their yachts. Thinking about dyneema standing rigging to ensure I can quickly ditch the rig in an emergency. A flooded hull will sit upright without the rig. Water in water has no mass. The keel will maintain stability. Whatever you do DON'T use expanding foam. The bubbles may be closed cell but the gaps around the bubbles aren't and will quickly fill with water becoming a problem rather than a benefit. This can happen from condensed water vapour. To stop this the foam needs to be completely watertight. Simpler and much lighter to build watertight, air filled spaces.
Bajansailor
Well-known member
Chris, James Baldwin agrees with you totally re building water tight air filled spaces - he wrote an article about how he managed to make his Pearson Triton 28' sloop Atom very close to being unsinkable by adopting this approach.
The article is here - lots of other good voyaging info on his website as well.
Atom Voyages - In Search of the Unsinkable Boat
The article is here - lots of other good voyaging info on his website as well.
Atom Voyages - In Search of the Unsinkable Boat
rogerthebodger
Well-known member
I collected all the single use plastic bottles and filled then with builders foam. I then packed all the bottles into closed but not sealed sections of my 3 meter tender and a 6 meter long motor boat.
This prevents the foam from getting water logged which it will over time. Its hell of a job to dig it out to replace.
I had to do that on some floats for my motor boat jetty at my condo
This prevents the foam from getting water logged which it will over time. Its hell of a job to dig it out to replace.
I had to do that on some floats for my motor boat jetty at my condo
Refueler
Well-known member
My 5m daysailor when I bought it from a couple of guys here was full of pop-bottles all tied together.
Yes I know ... they both need a good clean up !! The guys had crammed those bottles into every nook and cranny they could ... even filling the under cockpit bench areas which are supposed to be sea berths. Anyone who wonders what make it is ... its a Polish "Kormoran" - during Soviet time - quite a few were used by Marine Academy's for boat training, twin drop keels and no ballast ! I managed to save this last one here before it 'disappeared .... as so many items did ...
Yes I know ... they both need a good clean up !! The guys had crammed those bottles into every nook and cranny they could ... even filling the under cockpit bench areas which are supposed to be sea berths. Anyone who wonders what make it is ... its a Polish "Kormoran" - during Soviet time - quite a few were used by Marine Academy's for boat training, twin drop keels and no ballast ! I managed to save this last one here before it 'disappeared .... as so many items did ...
Graham376
Well-known member
When I built a grp tender, I built in some buoyancy compartments and filled with 2 part closed cell foam, which only took a couple of years to become waterlogged and heavy. Getting it out again was a pig of a job.
Old Harry
Well-known member
Leave room for accommodation, remember the "Unsinkable Titanic"!!!!!!
scruff
Well-known member
This is quite the thread resurrection - the original post is over 5 years old!