wave making

[nordvindcrew]

will dig out the information on Herreshoffs rowing boat, I may have mis-spelled the name, and include it in my next post. The boat is pretty conventional but is reputed to row very well. it would be too small for my brother and me. we are kind of on the heavy side 170 / 210 pounds and would weigh the boat down too much. A couple of years ago we did some work on a Skua rowing boat and then tried it out. slowest most erratic submarine in the harbor. That Stretched Gull rows with her fore foot just out of the water and on the power stroke you can see it lift up and go. I know it's not planing, but it looks like it's trying to, and the effect kind of gets to me as we try to keep ahead of them ( sometimes, not always ) It is kind of a small pond up here. the number of boats is small because we don't see all of them. Races are held from up in central Maine all the way down to New jersey. So far we only have competed here in Massachusetts. So far all the numbers on waterline and beam are just guesses. We've changed the original boat so much that we have no idea where it will really float. The bottom has a bit of vee but the next strake has a lot of flare where the waterline falls. Gone from 16'9" with a transom and a rediculous amount of rocker in the bottom to a 20' plus double ender with very little rocker. the pictures I posted are the two 8' bow sections with out the 4' mid section that will take it out to 20'. We're going to start joining it together this weekend by grafting in the pre-molded bottom panel and springing in some battens to start defining the sheer and chines. Sheer strakes and garboard strakes ( not sure how to name strakes on a hard chine boat , might be bottom, garboard, sheer or some other) will be fitted in to fair out the shape one piece at a time. A lot of head scratching and fitting, but there's a boat there just waiting to be completed

[melong]

Ok, cool. I'd be interested to see anything on the Herreshoff boat. I'm putting some more info in your other thread. Cheers.

[tspeer]

Originally Posted by Leo Lazauskas

...I've done this under for several existing shells. None of these shells are fore-aft symmetric and neither are my "optimised" variants. They probably would be symmetric if squat didn't play such a significant role: BL effects on symmetry are, in general, much smaller for these vessels....

I didn't think the BL was that important, but I couldn't think of another reason that would drive the asymmetry. I forgot about squat. No doubt that's also a driver for sections being flatter aft, so that they pick up waterplane quickly and minimize squat.

[EStaggs]

Alternating cadence is actually extremely difficult. It isn't so much the difficulty of retraining yourself from past years of trying to match cadence. The functionality of it is the catch and release would have to happen simultaneously. When one rower is in the power stroke, the inertia of the boat tends to pull anyone not rowing down the slide very rapidly. Coming up the slide at a rate exactly timed with someone on the power stroke is extremely difficult. Anyone that has rowed will know this, but to test it, get in your handy little skiff, take it up to 3/4 throttle, click the throttle shut for 1 second, then back to 3/4. This is the same load cycle as a rowboat.

Also, to spread your mass that far to each end would require tremendous length or additional buoyancy at the ends, eliminating your entry fineness for the sake of alternating cadence.

Interesting thread.

E