Posted by John Nichols on March 08, 2003 at -1:45:06 from 165.91.199.202 user Mcneacail.
In Reply to: Re: The design of the Swallow. posted by Jonathan Labaree on March 07, 2003 at 22:08:44:
Dear Jonathan,
Thanks for the offer. The drawings are a bit premature to plot at that scale.
Now this morning I was talking about the design.
The weight of the boat is a bit critical, and I have been looking at designs of that age in several Wooden Boat Books. Chapelle and Gardner.
The work boats of that vintage, such as the Pea Pod of Maine, had plank thicknesses from 3/8 th of an inch to 5/8 of an inch. The heavy lobster boats had the thicker planks. If some one could measure the thickness of the Amazon planks my guess is that they are 3 eighths of an inch if she was built for pleasure. The timber density is also important and my first thoughts are to use Western Red Cedar for the planking. It is light and I can get it from a place in British Columbia. The alternative is white oak. I am not sure I can steam Oak.But if it ss WRC then she can not be beached as she will have soft planks. A hard choice.
I have counted the frame spacing in a few of the sketches and it looks to be about 6 inches. They would be 0.75 by 0.875 inches in Spruce or Oak (White Oak)
The mast is 1/5 of the way along the length of the boat. I have done some preliminary bending calculations and I reckon that the mast at the base is no bigger than 4 inches in diameter, but probably not less than 3.5. Again if someone had measured Amazon that would be great. The boat was designed to work obviously and to be reefed so I am guessing they did not want the mast to break and also with no rigging the mast is a canterlever which is really bad for bending. No wonder it snapped when it hit the rock.
I am used to sailing Skates and VJ's and so I like a bit lighter boat. As long as it has a center board and floatation the worst that happens is I have a long bail job after I right her. (I have done that before).
Charlotte (my daughter) will be nine by the time I finish her, so she is old enough to be in a capsizing boat if that happens. What is that old saying Better ............................
The hull design program reckons she will have a speed of about 5 knots. The interesting issue is can I get her to plane. I have been looking at the Sail Design books and theoretically I could put enough power into her to make her plane downwind, but I am not sure I want that much sail.
The other difficult issue is how hard is the center bulkhead area. IF Nancy could outrun CF in his rowboat then that suggests not that hard as she could be rowed, but then her sailing goes off a tad. Also the AR sketches do not show the hull shape at the critical area well, although Swallow appears to be hardish and so a bit harder to row than a proper rowing boat. Also I am an amateur builder so I can not go to hardish on the shape or I will not have the skill to plank her.
So that shows some of the things that I am looking at. AR was a good drawer so it is not as hard as all that but I am trying to be careful.
I have not got a copy of PM (which is almost my most favourite) and I would love a copy of the picture of the Scarab to see what AR dreamed up for the boat he got to design. (Ed that is a hint).
Anyway it is late, I have been working on my desk (varnishing her.) She was built in the 1940's. I stripped her down, pulled her apart, and rebuilt her. If you look at the desk Mr Bumstead has in the comic you will see my new - old desk.
I would really appreciate any comments. I will try over the weekend to get all the files to David. I should be able to send the hull design file which can be viewed with a share ware program. It is great to be able to spin her in 3D.
Also has anyone seem the stem of Amazon and could give me a sketch that would be great. And if I knew the length of the real Amazon I could use that as a cross check.
Also my one dream is to sail her to the Island. Of course it is a dream but a nice one.
More next week. Ps this is a lot of fun.
John