Small boats, big water

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On an inboard with an engine mounted sea water cooling pump you put a 3 way valve in the pump's suction line. One side goes to the through hull seacock and suction screen and the other side has a hose and strainer in the bilge. Switched to the bilge with the engine running it will pump a whole lot of water.
 
Often we find that safety and connivence are at odds, and lots of people believe "it won't happen to me". We see this in homes, wit security bars and doors that are difficult to unlock (maybe requiring a key) and fires. Most likely it won't, but if it does connivence seems less important.
 
On an inboard with an engine mounted sea water cooling pump you put a 3 way valve in the pump's suction line. One side goes to the through hull seacock and suction screen and the other side has a hose and strainer in the bilge. Switched to the bilge with the engine running it will pump a whole lot of water.

A good Idea, but requires attention to what's in the bilge.

Uncles sailboat was rigged this way, and developed a leak along the shaft that was beyond the capacity of the electric pump (something broke and the shaft and prop departed the boat). There was about two feet of water on the sole. Activate the three way valve, and started pumping, sucked in lots of water. Sucked carpet scraps, paper and stuff on the sole up real fast and blocked the strainer (a big one with 1/2 inch holes).

Cooling water to the engine was restricted, and the engine overheated (according to uncle took about 5 minutes). Because of the bilge alarm, the engine noise, and distractions with the radio and stuff, didn't hear the engine alarm and didn't detect the problem right away. Luckily the costies got there with a BIG pump. Engine was fried.
 
A good Idea, but requires attention to what's in the bilge.

Uncles sailboat was rigged this way, and developed a leak along the shaft that was beyond the capacity of the electric pump (something broke and the shaft and prop departed the boat). There was about two feet of water on the sole. Activate the three way valve, and started pumping, sucked in lots of water. Sucked carpet scraps, paper and stuff on the sole up real fast and blocked the strainer (a big one with 1/2 inch holes).

Cooling water to the engine was restricted, and the engine overheated (according to uncle took about 5 minutes). Because of the bilge alarm, the engine noise, and distractions with the radio and stuff, didn't hear the engine alarm and didn't detect the problem right away. Luckily the costies got there with a BIG pump. Engine was fried.

Problem was a dirty bilge, poor maintenance, the electric pumps would or did plug from trash too.
As I said before it usually takes more than one thing to produce a bad outcome.
 
A good Idea, but requires attention to what's in the bilge.

Uncles sailboat was rigged this way, and developed a leak along the shaft that was beyond the capacity of the electric pump (something broke and the shaft and prop departed the boat). There was about two feet of water on the sole. Activate the three way valve, and started pumping, sucked in lots of water. Sucked carpet scraps, paper and stuff on the sole up real fast and blocked the strainer (a big one with 1/2 inch holes).

Cooling water to the engine was restricted, and the engine overheated (according to uncle took about 5 minutes). Because of the bilge alarm, the engine noise, and distractions with the radio and stuff, didn't hear the engine alarm and didn't detect the problem right away. Luckily the costies got there with a BIG pump. Engine was fried.

A bung to plug the shaft hole would have been a good idea. Back when I had my trawler I had ~6 different sized wooden bungs aboard and some scraps of rags. If you wrap a rag around the wooden bungs they can be sized to fit nearly any hole. All boats with thru-hulls below the water-line should have a selection aboard. They don't need to 100% watertight plug the hole, just stem the gushing so the pumps can keep up.
 
One other thing: DOUBLE, HIGH-QUALITY, hose clamps on the though-hulls,
and the other ends of the hoses, and everything else that's exposed to
outside water.

Drop into West Marine. They sell two grades of hose clamps. The lesser
ones (which are actually pretty good quality) have threads that go all the
way through the band. The good ones have threads embossed into the
band. That keeps the holes from cutting the hose, and makes the band
stronger.

One of the Monterey dive boats went down a few years ago because of a
hose clamp failure. They made it to a good shallow place (like three feet
under the keel) to sink, but it was out of service for a year or so. And
we've had a couple of fishing boats with the same problem.

You need to keep a big ass hammer with the bungs.

Me, I got a Boston Whaler. Leave the plug out, yawn.
 
Metal thru hulls! I broke a plastic one off once (above waterline thank god) but it was only and inch or two above and I didn't sleep that night. The fiber reinforced ones seems ok (maleron) but I prefer bronze. Its debatable whether leaving thru hulls unbonded is a plus or minus. I imagine it depends on how "hot" your marina is. For trailered boats its a no brainer.
 
The problem with the article is that it gives no reference as to what moderate rough water is and how small the boats are. It is very easy for the ocean to get too rough for small boats. I lost a friend who went fishing in a 21ft boat decked out to troll. Since every bit of water that went into that boat had to be pumped out with the electric pump we cautioned our friends about going out with winds gusting up to 30 knots. That kind of wind brings serious ocean white water for a small 20ft boat. They sank out in open ocean and were never found. A good ocean captain knows the size and make of his or her boat and what the limits are. If they are wrong it could be disasterous. It's been my experience when your ego is too big and you challenge the sea, you will normally lose. There is also the problem of spontaneous weather changes. If it is rough when you start your trip it could be overwhelming if the weather got worse. There will always be accidents but rough water boating should be done by the qualified and properly equipped. If your boat can't handle being swamped by a big wave you shouldn't be out in that boat that day. It's best to consider that before you leave the dock. Adventure-Ocean
 
https://www.shearwater.com/products/swift/

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