Like most emergencies at sea, lots of reasons, lots of solutions. Just another tool that is great in some situations but may not be as helpful or easy in others.
A waterproof or resistant barrier over a hull breach from the outside that water pressure help seal is great. ..getting it there, getting it to reasonably seal, and getting it to stay there in rough conditions presents a challenge. But look at the alternatives......
As far as I'm concerned, total automatically controlled bilge pump capacity on a boat should approximately equal the water ingress from a failure of the largest underwater fitting (typically a shaft log or engine intake thru hull)...
That's a great point. Welcome aboard
Also, be aware of bilge pump location. Our boats bilge pump is located near the stuffing box and all the thru hulls are in the engine room, separated by a bulkhead and about a 1.5" diameter limber hole...
*Note to self: Install a pump to the engine room.
__________________ "The most interesting path between two points is not a straight line" MurrayM
I've got a similar placement issue. The shafts and rudders will dump into the aft bilge (although water does feed to the engine room bilge). If there's enough water, it'll make it through the shaft holes in the bulkhead and end up in the non-draining space under the engines (unless it overflows the stringers, but that's unlikely without a totally missing shaft).
All but 1 thru hull is in the engine room, so that's the biggest point of concern. There's a single 3/4" thru hull in the forward bilge, but between a small pump in there and the limber hole to the engine bilge (which is downhill from the forward bilge), taking care of water from that would be no problem.
My boat has two fishholds, each with a ball-valved 1" thru-hulls (approximately 24" below sea level) to allow sea water in. Each hold also has an 800 gpm pump to take water out. The output of each pump also has a ball valve to restrict its flow. With both valves fulling open (so water is coming in thru-hull at full speed, and the pump pumping out as fast as it can), the pump can not only keep up with water flowing but full-drain the 250 gallon (?) hold in about 10 minutes).
My boat has two fishholds, each with a ball-valved 1" thru-hulls (approximately 24" below sea level) to allow sea water in. Each hold also has an 800 gpm pump to take water out. The output of each pump also has a ball valve to restrict its flow. With both valves fulling open (so water is coming in thru-hull at full speed, and the pump pumping out as fast as it can), the pump can not only keep up with water flowing but full-drain the 250 gallon (?) hold in about 10 minutes).
Then 800 GPH will handle a one inch hole. That is good to know information. Based on this article https://www.boatus.com/magazine/2014...p-capacity.asp that 800GPH pump is actually pumping 400GPH approx with a real world losses as manufacturers use ideal situations for rating.
Good info, a one inch hole needs a 800 GPH pump to stay even.
My current plans involve some manifolding to avoid needing to punch additional holes in the boat. 2 of my current close-together sink drains are going to be manifolded together onto a 1.5" discharge, freeing up another 1.5" discharge for the big 3700 gph pump.
And the aft head sink discharge is also 1.5", so provided I can test and confirm that there's enough vertical rise to avoid backing water up into the sink, the 1 1/8" discharge from the 2000 gph pump will get Y-ed into that sink discharge (on a vertical section of the run just before the fitting).
When sharing thru hulls, total flow capacity needs to be considered, as well as any potential back-flow issues and whether sharing leads to longer hose runs (with corresponding reduced flow).
My current plans involve some manifolding to avoid needing to punch additional holes in the boat. 2 of my current close-together sink drains are going to be manifolded together onto a 1.5" discharge, freeing up another 1.5" discharge for the big 3700 gph pump.
And the aft head sink discharge is also 1.5", so provided I can test and confirm that there's enough vertical rise to avoid backing water up into the sink, the 1 1/8" discharge from the 2000 gph pump will get Y-ed into that sink discharge (on a vertical section of the run just before the fitting).
When sharing thru hulls, total flow capacity needs to be considered, as well as any potential back-flow issues and whether sharing leads to longer hose runs (with corresponding reduced flow).
Just a thought: is your sink through hull at or just above the waterline? If so, you may be pumping against considerable back-pressure if the boat settles a bit and blast some of that water up through the sink drain.
Just a thought: is your sink through hull at or just above the waterline? If so, you may be pumping against considerable back-pressure if the boat settles a bit and blast some of that water up through the sink drain.
My drain thru hulls are all a few inches above waterline. That's a good point about what might happen if the boat were to settle down far enough in the water. Might need to look at popping an extra thru hull in there this winter to keep the 2 separate.
NERF footballs are very soft closed cell foam toy football
Great stuff foam
Truplug
soft wood plugs
toilet bowl wax
Never underestimate the value of spare pillows and foam mattresses. Those jammed into holes can buy you precious time to arrange other fixes and seek help via the VHF.
We have three bilge pumps with float switches. The main pump is the lowest, the next highest has a alarm hooked to it so if it comes on it also sounds the alarm to let you know that either something is wrong with the first pump or it is not keeping up. Then I also have a T valve in the suction side of the a/c pump (1hp for multiple units) so the pump can be used to pump the bilge.