Self-bailing boats at the dock . . . how do they work?

[PATRIOT]

Looking at aluminum boats that have self-bailing hulls. I understand how they work when underway (that whole negative pressure thing) but how do they work when moored at the dock with the drain plugs removed?

 

[PSG-1]

In a TRUE self-bailing boat, the deck of the boat is built above the waterline, and the deck scuppers are also positioned just above the waterline, so that any water will drain from the deck, with none entering the bilges or the hull, whether it's underway, or sitting at the dock. The only drawback is that you lose a lot of gunwale height, because the deck has to be built up at least 6" from the floor on the average johnboat.

As for the self-draining plugs with the flapper ends, I don't trust them, as trash can cause them to not close, letting water in the boat. And these don't work at the dock, because they're below the waterline, and there's not enough pressure against them to make them open and drain the deck.

 

[Keith1]

Back in the 1990s we were fishing for marlin in Los Barriles on the East Cape of Baja California. A boat sunk one day for supposidly no reason and they blamed something getting into the scuppers which I never understood at all.
I swam down and tied a rope onto the sunken craft so that they could refloat it. They used one of those commercial marlin boats to pull it to the surface. Ever time that they would stop the boat would sink due to being full of water. There was a big Mexican guy in the water with me so someone had the idea for him to get into the slowly [almost stopped] moving boat. Another boat brought a bucket and he started bailing the water out as they sped up to keep the boat afloat.

After being envolved with that operation I don't trust scuppers at all.

Regards, Keith

 

[PSG-1]

I had an 18 foot Alindale skiff sink at the dock one time. At low tide, it was on a slight angle, and when the tide came in, it flooded through the defective scuppers, onto the deck, and leaked into the hull through a bad seal in a deck plate.


Ever since that, I haven't been much of a fan of scuppers, either.

 

[Ranchero50]

Ditto, a lot of boats were lost on the Chesapeake the other winter from snow load making them settle enough to fill through the desk drains.