Hello Everyone,

 

My name is Guy and this is my first post in this forum.  I am here because I want to build a wooden drift boat and, undoubtedly, I will occasionally need advice of the pool of experts and experienced drift boat builders on this forum.

 

In preparation for this project I have read and studied three books: Drift Boats and River Dories by R. L. Fletcher, Boatbuilding with Plywood by G. L. Witt, and Covering Wooden Boats with Fiberglass by A. H. Vaitses.  I have also developed my own set of construction plans based off of the "Original McKenzie Double-Ender with Transom" in Fletcher's book.  I used and MS Excel spreadsheet to calculate all of the dimensions, cut angles, compound angles, and bevel angles of all frame components and I used Pilot3D software to calculate the as-cut dimensions of the plywood sides and bottom.  At this point I am pretty comfortable with the mechanics of construction and I think that I am just about ready to start purchasing lumber.

 

Presently, I plan to use Meranti Hydro-Tek plywood; 1/4-in. on the sides and 1/2-in. on the bottom.  I found plenty of places to purchase these materials, but they are all far away from Idaho Falls, Idaho, and as a result shipping costs more than the materials.  Are any of you aware of a business within a few hundred miles of Idaho Falls that sells this plywood?  I have a few requests in to the local lumber companies, but I have yet to talk with someone who has heard of this material before.

 

I also plan to use Port Orford Cedar (CVG) for the straight frame sections and White Oak (quater sawn) for the bent frame sections (chine logs and sheer rails).

 

Thank you, Guy

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or using 16 oz in  lb and 28.35 grams in an ounce

250 x 16 x 28.35 =  113,400 grams

 

 

 

sorry i guess my  question wasn't clear,heres what i'm talking about.

Guy wrote...Let's call this "The Three Amigos plus Dog plus Gear Float Test".

At 1/8th scale, a 220-lb man weighs 195 g.  The equation is:

(220 lb) x ((1/8)^3) x (454 g/1 lb) = 195 g

Mass is a function of volume, hence the cube term.

 

I returned from a six-day business trip on Sunday night.

 

The "scale" factor is a dimensional scale factor.  Basically, I considered a person to be a vessel of water containing 220 lbs of water and I scaled that vessel to 1/8th scale and recalculated the mass of water.

 

There are many ways to proceed.  I'll go right in to SI units.  A 220-lb person is 99.79 kg (the conversions are 453.6 g per lb and 1,000 g per kg).  A person is basically a sack of water, and water has a density of 1 kg per L, so the approximate volume of a 220 lb person is 99.79 L.  A liter is the volume of a cube that is 10 cm x 10 cm x 10 cm = 1,000 cm^3 (= 1 L).

 

At 1/8th scale, that same cube is 1.25 cm x 1.25 cm x 1.25 cm = 1.953 cm^3 (= 0.001953 L); remember, each dimension is 1/8th scale and 10/8 = 1.25.

 

So at "full scale", a liter has a volume of 1,000 cm^3 (1 L) and at "1/8th scale" a liter has a volume of 1.953 cm^3 (0.001953 L).

 

A "full scale" 220-lb person has a volume of 99.79 L and a "1/8th scale" 220-lb person has a volume of 0.1949 L (99.79 x 0.001953 = 0.1949).

 

Therefore, a "1/8th scale" 220-lb person has a mass of 194.9 g.

Using the same approach...

 

A 250-lb person is 113.40 kg (the conversions are 453.6 g per lb and 1,000 g per kg).  A person is basically a sack of water, and water has a density of 1 kg per L, so the approximate volume of a 250 lb person is 113.40 L.  A liter is the volume of a cube that is 10 cm x 10 cm x 10 cm = 1,000 cm^3 (= 1 L).

At 1/6th scale, that same cube is 1.667 cm x 1.667 cm x 1.667 cm = 4.630 cm^3 (= 0.004630 L); remember, each dimension is 1/6th scale and 10/6 = 1.667.

So at "full scale", a liter has a volume of 1,000 cm^3 (1 L) and at "1/6th scale" a liter has a volume of 4.630 cm^3 (0.004630 L).

A "full scale" 250-lb person has a volume of 113.40 L and a "1/6th scale" 250-lb person has a volume of 0.5250 L (113.40 x 0.004630 = 0.5250).

Therefore, a "1/6th scale" 250-lb person has a mass of 525.0 g.

thanks Guy,i had to read it a few times to get my head around it. 

Not that you can tell by looking, but that the second coat of epoxy!  I also got a second coat on the backer-board and the chine logs.

 

Tonight I pre-drilled both sides of the stem post and side panels to accept 3/4-in.-length #8 wood screws.  Then I epoxied and screwed one of the side panels to the stem post.  I did not over tighten the screws.  I just snugged them up to let some of the epxoy squeeze out of the joint.

 

Lot's of work, but little visual progress.  I just finished sanding the frames, chine logs, and backer-board after the second coat of epoxy.  Tomorrow I will apply the third and final coat of epoxy.  Then there is one more round of sanding, and then I will be just about ready (FINALLY) to attach the side panels to the frames.  I am really looking forward to that day.

Third and final coat of epoxy on the frames, chine logs, and backer-board.  Next it's lightly sand everything again with 120-grit to prepare the surfaces for varnish.

Today I attached the second side panel onto the stem post.  I want to give this epoxy at least two days to cure before I start stressing the plywood.  There is just enough room in the garage for this maneuver.  It looks like everything is in a state of chaos right now.  I still have to do the final sanding of the frames.

 

Guy,

The frames are looking good.  Can't wait to see them going together with side panels.

Keep up the good work.

 

phil w

Today is a good day.  It's starting to look like a boat.  So far, the frames are sliding right into place!

 

 

 

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