Plugging hull with balloon and foam

[steve]

I read about this system of plugging a hole in the hull on another forum. You stick in the balloon and fill it with polyurethane foam, which is supposed to plug the hole from the outside. Has anyone tried it?

 

[snowleopard]

I'd be interested to hear how it's done. How do you stop the balloon from bursting?

There's precious little strength in that stuff so you wouldn't want to go far with it as the only thing between you & Davy Jones.

 

[Guest]

Love to see someone try it ..... have you ever tried plugging a hole big enough to do this ??

Best is the bin liner and bits of rope over side .... water pressure holds it against hull etc. I've salvaged a Waterwitch like that .... plus passed it onto others to use.

I can see the idea ... a ballon of air would puncture .... with foam it becomes near puncture proof etc. But how do you do it while water is gushing in .....

/forums/images/graemlins/confused.gif

 

[tcm]

no. I've seen the umbrella things thos, they look quite good i spose, push umbrella thru the hole and open it and wham it gets pushed up against the hole.

Trouble with all thes things is you almsot never get a chance to usem....

 

[pappaecho]

When you use urethane foam you have to coat the surface with water so that the foam sticks... so it must be the ideal thing to use when the briny is coming inside, when you dont want it to.

 

[Talbot]

fothering with the bin liner or some other material from the outside is the best aproach for immediate stopping water from coming in (or at least slowing it down enough for the pumps to have a chance.) You then need a system to be able to make a temporary patch from the inside. In most modern boats this is very difficult because of the interior mouldings. In the short term it may be more effective to supplement the exterior fother with a more robust cloth sufficient to be able to get to some shore where better repairs can be made.

 

[jerryat]

Hi tcm,

The problem with the Subrella type (umbrella) unit IMHO, is how the hell one gets it through the 'hole'. Most hull damage tends to be impact from the outside, so timber, grp etc will be pushed inwards. With either, it's extemely unlikely that a HOLE will be formed, but more a sort of split in the structure.

I was given one of these (Subrella) units by a kind friend as a present when we set off cruising, and having played with it, can see no way one could get the whole thing through the hull without there being a pretty big clear hole. And you can imagine the volume/pressure of water coming at you in those circumstances!!

If you look at the instruction pictures, sure enough, there's a nice big, clean cut hole - and NO water! I've played with the thing and reckon the hole would have to be 100-150mm in diameter to have a chance of getting it through.

And all this assumes (as Talbot rightly points out) that you can get to the hole anyway with a system this long.

I'm not knocking the idea, just highlighting some of the perhaps not so obvious potential problems.

Cheers Jerry

 

[Guest]

For Centuries ....

The answer has been the Collision Mat. For the precise reason that 'holes' are for Hollywood only !! The normal 'leak' is a split or crack that 'umbrellas / soft wood plugs / balloons etc.' will have no use for.

The bin liner / plastic bag or whatever you have available is the best way for ALL holes / splits / cracks etc. Even the broken sea-cock.

Its funny that on many things - new ideas spring up and often people return to the old ways ...

 

[tcm]

yes, of course you're right - it wd have to be a sudden and very neat hole- unlikley in the extreme. I have used the sttuff in Kollision Kit from Force 4 or crack etc - very good for sealing when there are wet surfaces and even underwater.

 

[Das_Boot]

An old tractor tyre works best split along the length and lashed over the split, hole or whatever It can be pulled pretty tight and will exclude almost any water from getting in. If you have a wet suite it is better to go over the side and position whatever you are using. When chartering in sa in small boats (fishing) I have had to use this device twice and it worked well. Our boats were made of ply and were prone to a little splitting when you hit something at speed.

 

[Graham_Wright]

If the boat interior is partitioned with a view to surviving a collision (like what mine is Jonas as I am), then I guess there would not be an inrush of water once the levels inside and out had equalised. It would then be less difficult to make a repair albeit under a foot or two of water prior to pumping out again. With planning, it is not so difficult to introduce (fairly) watertight compartments particularly in the more vulnerable areas (such as the bow). The saloon is the weak link but maybe is the least vulnerable. The heads where there is a sufeit of intentional hull holes should succumb to a removable panel fore and/or aft which does not need to be substantial as the water differential pressure is not great. Even if it leaks round the edges, it will slow down the influx and buy time.

 

[jerryat]

Hi Graham,

I sort of see your point, and on a bigger boat semi-watertight (?!) panels might be a good idea. But it isn't really practical on a small boat like ours, usually fully laden with full time cruising stuff. As it happens, in the event of hull damage, once the stores have been shifted from the relevant locker/area, we can get at virtually every inch of our hull to jam something into the split or whatever, so we could do something.

My previous post was pointing out that even with NO water coming in, the Subrella cannot be pushed through anything other than a hole - it would be impossible with a (more likely) split. /forums/images/graemlins/frown.gif

I'm not sure about the pressure differential not being great, it seem bl**dy enormous to me when I remove my log for cleaning, and that's only a relatively tiny hole!! Generally see your point though! /forums/images/graemlins/smile.gif /forums/images/graemlins/smile.gif

Cheers Jerry