Guy's Wooden Drift Boat Project

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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Permalink Reply by Guy Fredrickson on January 22, 2012 at 11:32am

Third iteration is a charm...

Here are some pictures of the second model.  This time it all fit together perfectly.  I taped the stem and then started insterting the frames.  I started with frames 1 and 6, and after that the rest of the frames just fell perfectly into position.

These first three pictures show the side frames being prepared.  I taped small battens into positon to help guide the frames and it helped tremendously.

These next three pictures show the frames lined up in different ways.  The frames go from 1 to 12, from the transom to the stem.

These next four pictures show the model taped-up and ready for glueing.

 

 

Permalink Reply by Dave Z on January 22, 2012 at 4:12pm

Nice progress.  Glad you decided to build models.  They all look pretty good.  You are probably good to go to real materials if you are satisfied,  or consider building a wood model. Get some scaled lumber and get it as right as you can.  remeasure off the model and compare with your plans.  This is exactly how I designed my boats.  the difference is I drew a few simple lines and went straight to models, then tweaked them in the interest of material savings.  I wasn't too committed until I was satisfied with the models. 

Good work.

Permalink Reply by Guy Fredrickson on January 22, 2012 at 6:07pm

Thanks Dave.  Building that model saved my... bacon.  My spreadsheet calculates all of the cut angles for the frame members.  My plan is to start making the frames and compare the angles to the model as I go along.  The overall frame dimensions are perfect, and the angles seem reasonable.  I will check the calculated angles (bevels, compounds, etc. against the model to make sure).

Permalink Reply by Guy Fredrickson on January 22, 2012 at 6:31pm

This seems to be it...

The overall length is 16 ft and the widest beam is at dead center (Frame #7).

At Frame #7 the beam is 56 in., the distance between the sheer rails is 76.5 in., and the elevation of the sheer rails is 24.5 in.

This picture shows the side panel relative to 10-ft length 1/4-in. plywood with scarf joints.

This picture shows the "bend curve", which is composed of two catenary curves, one rear of dead center and one forward of dead center.

This picture shows the tranditional plan and profile views.

This picture shows the frame placements.

Here is a series of 3D renderings.

And here are pictures of the finished model.

 

My plan is to order the frame lumber this week.  When the frames are finished, then I'll order the plywood and lumber for the rails and logs.  I will probably keep the inside a wood finish and fiberglass and paint the outside.

 

Thank you everyone for some great advice up to this point.  The things I learned here were truly invaluable to the design effort!  I'll post my progress as this project goes on.

 

 

Permalink Reply by Dave Z on January 23, 2012 at 7:47pm

Guy,

It looks great!  That's a nice looking model!  Now... 12 frames?  Have you considered re-spacing them and eliminating a few?  You probably could get away with 8 or 9.  Or half height frames on every other one... hmmm... that could provide some interesting rail fastening systems...I'm going to throw that idea in the memory bank.

Dave

Permalink Reply by Guy Fredrickson on January 24, 2012 at 6:36pm

Dave Z,

Thanks.  Why 12 frames?  Just because.  I really like the look of the frames running the length of the classic wooden boat (drift boat, canoe, what ever).  So I decided to exaggerate that aspect a little on this boat.

FYI

As a result of my postings on this website, I now know two others in Idaho Falls who are building drift boats.  One has already started and one (happens to be a coworker) is just getting ready.  I think that's awesome.

Permalink Reply by Andrew on January 25, 2012 at 8:12am

Guy, 

That is some amazing work on the spreadsheet.  

If I would have had something like that it would have saved me so much brain power that I used when planning my boat. 

Kudos to you sir, 

Andrew

Permalink Reply by Guy Fredrickson on February 13, 2012 at 10:57am

The Port Orford Cedar for the frames arrived today!

These guys did a great job, they are out of Winthrop, Washington.  Just look at that crating and packing.  And the wood is CVG quality.

 

 

 

 

 

Permalink Reply by Guy Fredrickson on February 18, 2012 at 7:09am

I finished the 1/8th-scale wood model of the boat.  It's not my best work, but it certainly served its purpose and I learned a lot.  The frames and panels went together perfectly, which means the spreadsheet calculations are dead on.  In assembling this model I learned the following.

1) What cut angles are important to know to setup the saws.

2) What dimensions are important to know to layout the patterns on wood.

3) What design features to think about more carefully with regards to the transom, how the inside rails engage the side frames, and how to terminate the rails and chine logs.

4) How to use battens to align the frames while brining the two side panels together.

5) The difference between thick and thin expoxy. (You can see some nasty glue lines.)

Here are some pictures.  Please take a look and let me know if you see anything that doesn't look right with regards to the overall dimensions.  Thanks, Guy

 

 

 

 

 

 

 

 

 

 

 

Permalink Reply by Rick Newman on February 18, 2012 at 8:18am

Guy, you have really gotten the boat building thing. From concept, spreadsheet, reproductions, models, revisions, buying lumber and finally a working model. Your first post was January 6th and at this pace you will probably have your boat on the water by April 20th, just in time to show it off at the McKenzie River Wooden Boat Festival. we can provide a map to the site, but I'll bet it is already programmed into an Excel spread sheet!

What do you do in your spare time when you aren't building or thinking about your drift boat? Thanks for sharing your trials and tribulations, this is what makes this site work! There are many hundreds of members and many more joining weekly that get to learn from what you and others have done. The process of design that you enjoyed and your novel approach using the spreadsheet will no doubt inspire others to try their own hand at designing their own boat.

By the way your model really looks great and I am sure that the educational process you went through will pay dividends when you build the real thing. How did you determine the bevel angles on ywo in your frame pieces where they met the side panels. It seems like you had a column or two in your spreadsheet.

Keep on sharing your build, it is inspiring to me and makes me want to get back out in the garage/storage area/boat shop and get my boat finished so I can display along side yours at the wooden boat festival!

Happy sawdust to you,

Rick Newman

PS I have never ordered any wood from Bear Creek lumber but I thought that they had some nice wood. Glad to see that they came through so well.

Permalink Reply by Guy Fredrickson on February 19, 2012 at 8:45am

Thank you Rick.

The frames are perpendicular to the chine edge.  The curvature of the chine edge is mathematically defined by the catenary curves.  That gives me an X-Y-Z coordinate for each side of the ¾-in. wide frame lumber.  From that information you can use trigonometry to calculate the bevel angles.  The same approach is used for the side and bottom bevels.

I have a friend who is a sports fishing writer and we plan to write this up in an article.  If we do, I’ll post the information here.

I am now a strong advocate for building models prior to the construction effort.  I avoided a disaster by doing just that.

Guy

Permalink Reply by Guy Fredrickson on February 20, 2012 at 6:33pm

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.

Each bag of water in the photos is 195 g.  Fully loaded with the equivalent of 880 lb, the boat drafted 1.125 in., which is 9 in. at full scale.

The results of the load test are:

     1) Unloaded: 5 in. draft

     2) 220 lb: 6 in. draft

     3) 440 lb: 7 in. draft

     4) 660 lb: 8 in. draft

     5) 880 lb: 9 in. draft

I've got nothing to compare these results to.  But it looks right.

 

 

 

 

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