Boat design/construction to include separate water tight compartments?

17 years 1 month ago #170 by HI Paddler
After reading the story about the two-man crew whose ski's nose broke off, and how the boat was barely keeping them afloat, I started wondering how difficult it would be (or I guess, how much more expensive it would be) for boats to be designed and constructed to have several (perhaps 3) separate water tight compartments so that if the nose or tail breaks off, the rest of the boat would still float and could be used as one's PFD to either limp to shore or hang onto until help arrived.

I'm sure it would add some weight and dollars (or whatever) to the final cost of the boat, but it seems like it could help increase the safety of the sport.

Please Log in or Create an account to join the conversation.

17 years 1 month ago #171 by AlanC
From what I have been told, sealed bulkheads and "flotation" chambers are not the safest way to go.

Many safety standards require positive flotation material (i.e. some types of closed cell foam) in empty spaces. In the case of a hull breach the volume of water that can enter the hull is minimized while still maintaining some flotation.


Please Log in or Create an account to join the conversation.

17 years 1 month ago #172 by opskop
I think HI Paddler was talking about incorporating bulkheads into the current design, ie the bulkheads would still contain the required positive flotation material inside of them, thereby still maintaining positive buoyancy in the event of a breach. The benefit being that the volume of water which would enter the ski greatly reduced.

I dont know much about ski construction but I think that the foam in the ski's are also structural members which provide rigidity to the ski. If bulkheads were to be introduced, and hence foam separated into respective bulkheads, then how would the foam provide enough rigidity?

What we need is a boatbuilders perspective...

Please Log in or Create an account to join the conversation.

17 years 1 month ago #173 by HI Paddler
I'm no expert on boat building by any means, and the responses to my post shows that others have considered and discussed this issue. It just seemed to me some additional measures taken to prevent boats from sinking might aid paddlers who encounter boat failure in a situation where it is not easy to reach the shore - such as Oscar's long swim.

Even when broken in half, surfboards, made with some type of foam core, provide surfers with a floatation device (of course assuming they don't lose the board entirely) to get to shore. If the board is made of closed cell foam as with some epoxy boards, it conceivably could float indefinitely even though the foam is fully exposed to water.

Please Log in or Create an account to join the conversation.

17 years 1 month ago #174 by [email protected]
It would be interesting to hear from the boat builders but I don't believe you could make watertight compartments without radically increasing the weight (and build complexity) of the ski.

The difference between my 12kg carbon ski and my 17.5kg glass ski is such that I'd simply not want to paddle a heavier ski.

Having said that I do want a ski that floats even when waterlogged - it's much easier for rescuers to spot a large object like a ski in the water than a swimmer by himself.

As far as I know all skis float when waterlogged (including the Epics) so for me the safety issue is covered off - I believe the compromise of performance (ie lightness of the ski) v safety (the ski does still float when waterlogged) is right.

A further thought is that skis are so unstable as it is that I doubt it would be possible to stay on a ski that had, say, a quarter of its hull flooded ie I doubt the whole concept of water tight compartments is practical anyway.

But how's this for folks who are really worried about this: hatches in front and behind the cockpit allowing access to the hull - and specially designed (light) bladders that can be placed and inflated on either side of the stringer in either end of the ski.

They'd be a hassle - you'd have to service them, check that they were inflated, their weight and the weight of the hatches would be an issue.

just a thought!


Currently Fenn Swordfish S, Epic V10 Double.
Previously: Think Evo II, Carbonology Zest, Fenn Swordfish, Epic V10, Fenn Elite, Red7 Surf70 Pro, Epic V10 Sport, Genius Blu, Kayak Centre Zeplin, Fenn Mako6, Custom Kayaks ICON, Brian's Kayaks Molokai, Brian's Kayaks Wedge and several others...

Please Log in or Create an account to join the conversation.

17 years 1 month ago #175 by Noise Under The Bed
adding some screw in type inspection port hatches and vinyl float bags wouldnt add to much weight, maybe a pound or 2. And Just place and inflate the bags before each race to make sure they arent leaking.

Please Log in or Create an account to join the conversation.

17 years 1 month ago #176 by Dale Lippstreu
Foam cores have 2 distinct disadvantages. Firstly foam is heavy ? it only feels light because of its low density / volume but in real terms it is heavy in the volumes required. Secondly it absorbs moisture and retains salt both of which lead to a gradual increase in weight which can be material over time. The fact that is bonded into place adds to the weight particularly if an absorbent ?glue? like urethane foam is used.

Water tight compartments offer a potentially lighter solution but keeping the weight down and proper fitment will require precise manufacture with cost implications. The compartments could also be easily compromised without visible damage to the exterior of the ski e.g shear away from the hull if the ski is dropped.

Inflatable ?balloon like? ballast seems like the best solution. There are many lightweight polymers available which are extremely durable so it would not be too difficult to find a material that would easily outlast the ski exterior. In fact with the right material I do not believe that it would be necessary to have inspection hatches for maintenance purposes. A moderate pressure would be sufficient to lock the balloons in place and locating them fore, middle (in the bulge under the knees) and aft would ensure that there was flotation under almost all breakage scenarios.

Of course it would to take a bit of R&D on the part of the manufacturers and possibly a bit of development to implement but the ski building industry has reached a stage where this is easily justified.

Please Log in or Create an account to join the conversation.

Latest Forum Topics