Diesel Duck 382

Diesel Duck 382
Diesel Duck 382 with the "get home" steadying sails up.

Monday, September 18, 2017

Size Matters

Working alone allows for the true mental decompression that woodworking affords.  However, when building a boat, working alone has it's limits.  I am approaching those limits when dealing with the various laminated timbers that make up the keel.  When you start gluing up 8, 10 or 12 layers of wood, some 10 feet long, weight starts becoming an issue!

The last couple weeks have been devoted to machining, flat and square, several pieces of larch and white oak.  In a perfect world, based on the plans, I would know exactly how many boards each piece of the keel needed.  However by the time I machine my boards flat they are often thinner than described in the plans and therefore more pieces are required to make up the lamination.  This really is my own fault as I did not order my lumber thick enough.  I know better and I'm not exactly sure what I was thinking but I ordered my lumber for the final dimensions indicated in the plans.  I did not take into account the waste that would be required when the boards were run over the jointer and through the planer.  I guess my mind was in dimensional lumber mode where the lumber is already machined smooth and flat.

Our white oak is gorgeous stuff, I feel bad using if for boat timbers and not furniture.

Not that big of deal but food for thought going forward for future lumber orders.  I took the patterns we made back in the winter and taped them to the side of the lower keel assembly.  I then began to stack the machined boards up enough to cover the patterns.

Once I had what I needed I glued them up.  Depending on the type of glue I used determined whether I felt the need to glue them up as one piece or in sub-assemblies.  I used resorcinol for pieces that would be submerged, I used plastic resin and Titebond III for assemblies that would be wet but not submerged.  After having a great conversation with an engineer over at Titebond, I will now only be using TBIII and resorcinol.  Plastic resin glue really does not offer any advantages in this application besides a slightly lower cost.  If you want to learn more about my conversation with Titebond, click on the "materials" tab at the top of this post.

After each piece had time to dry, the clamps were removed. The sub assemblies, if necessary, were glued together as well.  Most of the laminations are larch but I'm using white oak for the stem.  White oak is quite a bit heavier but it's also stronger.  I think that is important for the stem and the stresses I may put it under.

White oak stem, glued with resorcinol.
This past weekend we got out the big timber frame saw again in preparation for cutting the laminated timbers to shape.  Just like when we cut the knees, we laid the patterns on the laminated "blanks" and traced out the shape with a wide tipped marker.  This is an effective way to give a nice clean line under the pattern for the exact size of the piece.  By using a wide tipped marker, the outside of the line provided a nice parallel cut line allowing us to cut each piece oversize with plenty of extra for final fitting.

You can see in the pictures that the red marker line is still visible, indicating we still have some work to do with the planer to get it to it's final dimension.  This is exactly what we want, margin for error!

Transom support. (not sure of the real name)

Stem forefoot
It takes two passes with the timber saw to cut these pieces to size.  By using a reference mark on the timber and on the pattern I can cut one side, flip both the piece and the pattern over in a mirror image and cut the other side.  The cuts line up very close, but not perfect.  A few passes with the power planer smooth out any inaccuracies.

You can see in this close up of the stem forefoot how the TBIII penetrates the fibers of the wood allowing you to cut and plane the laminations to a feathered edge.

Once the cuts were complete I took a rough measurement off of the plans and placed the forefoot where it will be installed.  It's a good feeling watching the keel take shape.

We still have two more laminations to glue up and one of them is over 17' long!  I'll have to get my father involved again for that one.  I better hurry while we have warm temperatures and before he goes in for another knee replacement.

The summer is winding down and we've been blessed with warmer temperatures.  It's actually been warmer in September than in August so we will probably be making a trip to the lake this weekend. The nice part about this part of the project is that the machining of the boards can be done whenever I have a little time.  I can do a few after work each night then do the glue ups on the weekends.

We'll continue to press on as time allows.  With school back in session and the related activities, time is often a rare commodity.  I continue to really enjoy the time that I do have to devote to the project.

We press on in pursuit of our dream and we hope you find time to work on yours as well!