Agree on the Epoxy putty. Used it on aluminium hull , now 2 years old and seems good as gold

Don ,that stuff looks quite good - the Stayafloat putty.

I haven't used it but it seems very different to Epoxy putties like KneadIt which I have used:

- Its a "bulk" putty for large holes and crevices (you would need at least 8 epoxy sticks to make up the same volume)
- Does not go hard like epoxy (so you can easily remove it after the emergency)
- Can be used instantly (to mix 8 whole epoxy sticks would take me more than 10 minutes; a lot of water can flow in that time)
- Easy to mix with wood or other materials to bulk up the putty

I'm so impressed I'll be trying to get some. For small holes etc. epoxy putty would work fine, but for bigger gashes and tears this stuff this looks real good to me.

Did you see it for sale in Australia somewhere?

Morningbird, would much appreciate it if could post how you go with the local distributor.

Will do Karsten. I have just had a leak from my stern tube which this would have been ideal for. It wouldn't prevent the rebuilding of my shaft arrangements, but it would have solved my immediate problem.

No need to use the expensive stuff, just any old builders expansion foam from Bunnings will do the job.

We had an old trawler with extensive leaking problems [like need to fix right now!]
and they just used the foam anywhere they could see water coming in.

When the boat was craned out it had foam expanding out all over the place from between the planks, but it did stop the leaks!!!
I think the owner was shocked at the amount of foam hanging outside the boat!

Gotta smile at the quick thinking

If you have a large hole, 2 inches or so below the water line the only way to repair would be a solid patch screwed to the hull or a sail pulled over the hole.

Years ago after I tied back up at the wharf in my fishing vessel I was down in the engine room shutting off the batteries and could hear running water. I chased it down to the stem where some packing had come out and water was running in at several gallons a minute about 2 feet below the waterline. Launched the dinghy and I sat in it kneading up Knead it and passing it down to one of my deckhands who forced it into place with a wedge. Next time we slipped we could not dig it out, its still there.

I don't know how they got such poor pressure through the valves in that video. I have dissembled 2 inch skin fittings and had water come through as a solid jet 2 to 3 feet into the engine room [I had the pumps running in preparation] Holding hands over the fitting was near impossible. It certainly would not stop the leak I had from the inside. It would work as seal when applied to a solid bung or board to block a leak if it is jammed in position. Not a chance of sealing split rubber hoses. I was highly skeptical after seeing the video!

Imagine boats like Koomaloo being lost and there is a product like this available!

At $13 it is certainly good value and I would have no hesitation smearing it over a tapered bung that we all carry tethered near our seacocks.

I think someone in another forum somewhere said that this is repackaged stuff that plumbers use to seal toilet bowls. I couldn't find it in my initial, half-hearted search.

Also, I read the packaging on some kneading epoxy putty the other day. It said that it contains an ingredient known in the state of California to cause cancer. Strongly advised against skin contact and breathing the fumes and, importantly, the dust from sanding the hardened material. Would you always know what you were sanding in a second hand boat? Crikey.

California also decreed that bullets can give lead poisoning !

Water pressure = density of water x depth x acceleration due to gravity

Hence, water pressure is a function of depth only. The water at a depth of 6 feet is 2.7 pounds per square inch ( in the old measurements) and half this at a depth of 3 feet. The squirt you will get into the boat therefore just depends on how deep the hole is in the hull.

If the hole is 6 feet below the water line and the hole has an area of one square inch it will take a force equivalent to the weight of 2.7 pounds to stop water flowing into the hull. You could test any sealant (assuming it only has to hold leaks to a depth of 6 feet) by seeing if it will hold on when a few pounds per square inch pressure is applied to it.

To do this, drill a 1" area hole in a sheet of ply, hold the sheet horizontally on the surface of a water bath, seal the hole with the goo being tested and then put a dowel into the hole about the same area as the hole with a few pounds of mass on it. If the sealant holds the dowell and mass up for the rest of the day it will probably stop a leak at a depth of 6' in the ocean. OR simply seal the end of a long pipe and push it vertically into the water to the depth being tested and see if any water gets into the pipe

Cheers
Mark (physicist)

No, boat weight has no effect other than often causing the hull to sit lower in the water (buoyancy requires the mass of water displaced by the submerged hull to be equal to the displacement of the boat). A hole in a submarine at depth would produce a jet of water that would be difficult to stop. A classic experiment to show how pressure changes with depth (you have probably seen) involves filling a tank with water and letting it leak out through holes drilled every few inches vertically in the tank. Water dribbles from the top hole but squirts further from the tank progressively as you look at each hole further down the tank.

You should be able to hold a rubber stopper in a seacock/ through hull but you will have to keep pressure on the stopper, it will not stay there alone. A rubber stopper will stay and stem a leak in a through hull provided it is inserted from the outside of the hull.

A hammered in wood plug stays in because the wood swells when wet and jams tight in the hole. That is why we 'all' tie wooden plugs to our through hulls.

Storm Petrel is right on the money.

Applied Force on the plug = Pressure x Area

Its all about the diameter of the hole (area) and how deep (pressure) the hole is below waterline. Hull shape may dictate how deep your skin fitting is below the waterline, but thats it.