Couple of (novel?) ways to stay afloat...

[JeremyFowler]

Carry a few uninflated dunnage bags onboard. When it is clear that the inrush cannot be contained use the dinghy inflator to pump them up in various locations onboard.

Use the engine water pump">raw water pump to suck the water from inside the boat by closing the thru-hull and pulling off the strainer top.

Yes? No? (I can't find any threads dealing directly with these concepts.)

[wholybee]

The raw water strainer should be the highest part of the raw water system, so you can remove the cap to clean it without it emptying the water in the engine and heat exchanger. That means that if water in the boat is high enough for it to be an intake, the engine is completely submerged.

Dunnage bags could potentially work, but I think you would need more than a few, and the boat would probably still be a total loss, but would float enough you could potentially stay on deck until rescue.

[JeremyFowler]

I have my raw water strainer low, screwed onto the thru-hull. This way there is less chance of an air leak destroying suction unknowingly. I'd rather have a drip than an airleak. After cleaning the strainer I'm more aware of whether water is coming out of the exhaust or not than otherwise, therefor the initial temporary loss of water in the system is not a problem.

[Nekton73]

To know for sure how effective the water pump idea would be you just need to time how long it takes to fill a known quantity container with water with the outflow. I think a couple of high capacity bilge pumps, like 2000 gph or more, would be more effective. As long as the engine is running you have electricity to run the pumps.


The inflatable flotation bags is interesting. I think it's been discussed on the forum before. Again though, the amount of volume your dinghy pump puts out will determine how effective this strategy could be. Once you determine how much flotation it would take to actually keep your boat from sinking, and where you could deploy it, you will be able to calculate how big a pump you need to inflate them in a given amount of time. For a quick idea though, consider how long it takes to inflate your dinghy and how many you would need to keep your boat afloat if you could stuff them inside.

[stormalong]

A collision mat would be more effective than a dunnage bag. Pulled across a hole/damage on the outside of the hull, water pressure pushes the mat over the hole slowing or stopping the inflow. A sail can be used to do this. From the inside of the hull there will probably be too much structure in the way to get a clean seal.

As already noted, the raw water intake of an engine is actually very low flow.

[NorthCoastJoe]

That would be a lot of air. A steel 72cf scuba than is about a telephone booth's worth of air. Um what is a telephone booth? My boat would need 460 CF of air to stay afloat. That would be a big raft. About 7 scuba tanks of air.

[BobFord]

What about a man and a bucket !?