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dcnblues

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I'm looking for a hydrodynamic analysis of a concept to design a custom rowboat hull with a smooth tubular bilge that could let water slide up above waterline, then down and out of the boat under the acceleration of the oars. Basically, I'd like to be able to row in choppy ocean swells without having to stop and bail water out manually.

I'm curious about dimensions: whether a larger diameter bilge tube would be better, or smaller. About whether narrowing the tube would provide any kind of venturi / Bernoulli increase in pressure that could help the water climb above water line before flowing out. I need some help calculating how much acceleration would lift how much water how far, and under what conditions.

I'm pretty sure that would work, provided the tube was full of water. A smaller tube would then be more efficient, but only get so much water out with each stroke of oars. A larger tube would be more efficient should the boat really get swamped with dozens of gallons of water. (I'm thinking of a boat with enough reserve buoyancy that one could sit and row even if swamped).

Some details: it would be composite, I'm considering a wave piercing hull shape, but regardless it would be low windage, 18-20 feet long is optimal for speed v drag, sliding seat design, probably around 100 lbs, narrow, and with a low CG for stability (so the bilge would definitely be below water line).

I'm imagining a flexible hose for the gooseneck, something which could be lifted for higher waves, or lowered to negligible height for smooth conditions (it would slide inside a tube leading to the draining scupper).

There are other details, and I have a thread on boatdesign.net here which would be a convenient place to give me some numbers / resources. I don't know where to start to figure this out, so any help most appreciated. Thanks,

*crap the title got eliminated for some reason. Could a moderator change the title to "Rowing the water out of a rowboat?"

I'm curious about dimensions: whether a larger diameter bilge tube would be better, or smaller. About whether narrowing the tube would provide any kind of venturi / Bernoulli increase in pressure that could help the water climb above water line before flowing out. I need some help calculating how much acceleration would lift how much water how far, and under what conditions.

I'm pretty sure that would work, provided the tube was full of water. A smaller tube would then be more efficient, but only get so much water out with each stroke of oars. A larger tube would be more efficient should the boat really get swamped with dozens of gallons of water. (I'm thinking of a boat with enough reserve buoyancy that one could sit and row even if swamped).

Some details: it would be composite, I'm considering a wave piercing hull shape, but regardless it would be low windage, 18-20 feet long is optimal for speed v drag, sliding seat design, probably around 100 lbs, narrow, and with a low CG for stability (so the bilge would definitely be below water line).

I'm imagining a flexible hose for the gooseneck, something which could be lifted for higher waves, or lowered to negligible height for smooth conditions (it would slide inside a tube leading to the draining scupper).

There are other details, and I have a thread on boatdesign.net here which would be a convenient place to give me some numbers / resources. I don't know where to start to figure this out, so any help most appreciated. Thanks,

**<< Link deleted by Moderator >>***crap the title got eliminated for some reason. Could a moderator change the title to "Rowing the water out of a rowboat?"

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