Friday, June 22, 2012
How to Make a Displacement Hull Plane
The Bartender line of fishing boats has a reputation as a superlative surf boat. The Coast Guard has used them as rescue vessels. As doryman everywhere know, a good surf boat is double-ended and is thus less likely than a square transomed boat to broach on a following wave.
Unfortunately the double-ended hull will not plane under normal, non-surfing conditions, no matter how much power they produce. So, George Calkins designed a spray skirt for his power dories to provide more lift at the stern.
The nineteen foot Bartender in the lean-to out in the boatyard has never been outfitted with a spray skirt, as far as I can tell, but it has one now. Frank, the current owner has been frustrated that this boat tops out at 10 miles-per-hour.
Now, that would be just fine with me. Mentioning this to Frank made him laugh.
If this were my boat, I'd have no more than a ten horsepower motor on her and be happy just puttering around. The hull drives easily and this could be a very economical package.
The boat has a 40 horsepower motor however, and a rated speed of 25 - 30 mph, which is what we are trying to achieve. The bottom had a keel hog from sitting on a poorly designed, dilapidated trailer which probably contributed to it's reduced performance. I've stressed as much of the hog out as I could, reinforced some old, tired keelson framing and re-welded the offending trailer. All in a days work for a shipwright. The spray skirt was a challenge - the hull shape aft has such a radical camber that the face of the skirt is a helix. I laminated Oregon white oak using polyurethane glue and stainless screws. Didn't have to steam bend anything, but very near.
Frank will be camping aboard this boat at the upcoming Sucia Rendezvous so I'll be able to see first hand how all this works out.
Hope you all had a better solstice than I did. You can see what I was doing on the longest day of the year.
The spray skirt meets the chine at the stern, sweeps up past the waterline about half-way, then on to touch the bow in a fair curve.
Need to clean and polish that bronze half-round for a finishing touch.....
I also prepared some salmon for the Rendezvous. John St Clair is known locally as the Salmonator. He is a prolific fish killer. (many people find it confusing that I spend so much time on the water but don't fish. With friends like the Salmonator, why should I?). Recently he gave me a 20 pound salmon that had been in the freezer for awhile. The best thing to do with a fish that's a bit past it's prime is smoke it. I don't have a smoker, so I slow cooked my fish. After marinating it in a brine and sugar mixture for 24 hours, it was spiced with garlic, onion, tariyaki and sesame seeds. It was then cooked at 170 degrees F, for six hours. Dessicated fish is not photogenic, so I will forgo any pictures. Take my word for it. It's delicious!