Random one for you

M

mattysupra

Active Member
Joined
11 Feb 2012
Messages
64
Visit site
Random question but something that I keep thinking about.
Jet Skis don't sink, they partially sink if fully filled with water but they will still remain afloat. They are specially designed to float even when totally filled with water due to floatation foam built into their hull.
So why are all boats not built like this?
Surely if all boats was built to the same design then a boat would never be lost. The boat would double up like a life raft as such?
Whats the reason why our boats are not built the same?
 
A handful of boats are built that way, but most would rather use the space for equipment and stowage rather than foam.

Pete
 
mattysupra said:
Random question but something that I keep thinking about.
Jet Skis don't sink, they partially sink if fully filled with water but they will still remain afloat. They are specially designed to float even when totally filled with water due to floatation foam built into their hull.
So why are all boats not built like this?
Surely if all boats was built to the same design then a boat would never be lost. The boat would double up like a life raft as such?
Whats the reason why our boats are not built the same?
Click to expand...
If your boat weighs 5 tonnes you will lose more than 5 cubic metres of enclosed unusable space inside your boat for it to be unsinkabe (not quite the correct figure but gives you the idea why most people would not buy an unsinkabe boat)

www.solocoastalsailing.co.uk
 
Last edited:
I used to have an ex ships lifeboat which had bouyancy tanks built in, that was an open boat largely styled on a bathtub with a tiny engine and it left precious little room for anything else. If you have a sleek designed cruiser and factor in the extra weight of a bigger engine (or 2), superstructure, interior plus fixtures and fittings you would need an Insane amount of bouyancy, there just wouldn't be the room.
A better design is individual sealed compartments, my old catamaran was built that way and I survived having 1 whole compartment flooded, I had a 20° list to port and virtually no steering but it made it 5 miles home under me own steam and got her pumped out.
 
tico said:
IIRC there was an advert for Boston Whalers being cut in half too and still floating. Mention it quietly but arn't ETAP yotties foam filled and unsinkable?
Click to expand...

You are correct, I’ve still got the BW brochure somewhere with a person in each half of the 2 bits of hull, still floating.
 
Some saddlers are "unsinkable" . The sea is at deck level when sunk.
Etap,s appear to sink by a very small amount.
Advantages are stated to be very well insulated hulls and no condensation.
Seen a fair bit about sadler insulation getting waterlogged.
Know nothing about etap.
Dorys were foam filled but after many years they end up having the foam removed due to water saturation and a large increase in weight
 
The vast majority of older sub 20 foot fast fishers are built this way. Over time the foam traps water which it doesn't release and causes more harm and damage than without. Loads of rebuild stories of having to replace decks and remove sodden foam cavities. Some replace with bottles and plastic pit balls, most just leave empty. I think jetski's are still relatively to new or simply dont make the age to develop these problems.
 
There is one I see in the Strait every now and again. Very odd seeing a yottie pick up his skirts and fly.
 
I can assure you...jet skis can sink. Ask any Seadoo owner !
Many boats claim to be unsinkable. Give them a few years and saturated foam and double hulls and they might not be so clever.
There was another similar claim made around 1912, I’m sure. ?
 
QBhoy said:
I can assure you...jet skis can sink. Ask any Seadoo owner !
Many boats claim to be unsinkable. Give them a few years and saturated foam and double hulls and they might not be so clever.
There was another similar claim made around 1912, I’m sure. ?
Click to expand...

People fall off too and they fall over from upright.

Never ridden one I really don’t want to, I’ve picked a few people up of the water from them.

An incident here a couple years ago when we were leaving the harbour - the local police rib shot
off somewhere at warp speed and turned one over. just as we arrived. We stood by them, the Coast Guard set them backup resolve the capsize they caused. I bet there was a few red faces aboard.

W.
 
Last edited:
You must log in or register to reply here.

Share this page

Top