Frame Wood Selection

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Frame Wood Selection

Post by getpower1 »

I’ve introduced myself, and I believe I have set my location, but in case not, I’m just south of San Francisco. I’ve received my plans and started going over things for my Ski Tow build.

We are still sourcing materials and working on that. Have called around to a few places and feel more and more like this build will be doable with my local resources.

One simple question that I have has to do with the frame building for the boat. My plans just specify 40 random board feet of 1” stock. I plan on using Mahogany, but oak isn’t out of the question for this application. But I can’t seem to wrap my head around what size width and length boards to buy in order to complete my frames.

Can anyone point me to an answer or maybe tell me a way to approximate how I can figure this out? Maybe measure the dimensions on the plans for all the frames, and get the total height and widths?

Seems simple. But not written on the bill of materials as to exactly what I need to source. Is there a simple “get X amount of 1”x8”x8” boards?

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Re: Frame Wood Selection

Post by DrBryanJ »

As far as frames and transom material, I don't think there is any list of specific lengths and widths of boards. You will get random lengths and widths. Then you lay out your patterns to get as much out of the boards as possible. I think the ski tow is 40 board ft. To figure board ft use the width of the board (inches) X length of board (Feet) X thickness (4/4 or 1 inch) and divide it all by 12. Remember the thickness in the plans is nominal. So where it says 1" the actual thickness is 3/4" thickness. A 1 X 4 X 8 is 2.67 bd ft. A 1 X 6 X 8 is 4 bd ft.

Building a malahini "Mona Lisa"

My wife said "If I build a boat, she's getting a divorce."
We're still happily married, but now she just wants "the dam boat out of the garage."

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Re: Frame Wood Selection

Post by vupilot »

My local supplier had 3/4" actual thickness African Mahogany in random length from 6-14 ft and width of about 7" to 14". Most were about 8ft and 7-8" wide. You just plan out the best you can. I had the luxury of having a supplier nearby which helped a lot.

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Re: Frame Wood Selection

Post by Hercdrvr »

If the lumber supplier is close I would buy just enough 4/4 material to build a couple of frames. I don’t recall the widths needed for the Ski Tow/Malahini frames but 6”-8” will get you started. Then you will have experience and a much better idea of the materials you need.

Matt B

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Re: Frame Wood Selection

Post by acflynn »

I agree with Matt. I'm building a Mist Miss, which is a bit longer at 18' and requires 75 board feet for frames. My local woodworkers supply has mahogany in 4/4 and 8/4, and for the frames I'm just choosing the straightest boards with the straightest grains (some were a bit twisty and cupped). Most are between 6" and 9" in width, one is 11", and all are 8' in length. Based on the plans, I've been able to get 4 frame member pieces out of one plank (two bottom members and two side members). Others I've had to use the entire plank for one frame member to accommodate the curve, such as the deck beams, which for me are just over 7' in length, and only 3" "thick", but due to the curve take up an entire 8"-wide mahogany plank.

I would suggest checking the plans for the widest boards you require (likely either the arched deck beam or any one-piece bottom frame members), and then even sketching out and estimating how many pieces you'll need. My first trip I picked up 45 board feet, which was enough for 4 frames, knowing that I'll go back and get the rest at a later point. But my supplier is only 20 or so minutes away. I'm only worrying about the frames at this point for me. Everything else is a "next year" (2020) problem.

Also, it doesn't help you now, but as soon as you start cutting your timbers you'll figure it out pretty quickly. I was apprehensive at first, but once my first cuts were made, it was a big confidence boost and I started optimizing my boards for the least amount of waste. I turned the corner with a big "Ah, I get it!". Hope that helps! Best of luck with your build!
Slowly building a Mist Miss in the Arizona desert

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Re: Frame Wood Selection

Post by TomB »

An added note on deck beams.

As acflynn mentioned, the deck beams need some width to accommodate the curve, say 8". There will be some waste as you get 3" from 8". A multiple of 3" wider board, say 11" or 14", will get you two or three beams by nesting without increasing the waste. And, while the plans call for a curved underside of the deck beams, leaving the bottom of the dash deck beam straight will make mounting the dash easier.

In the home stretch on a Tahoe 23

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