Part 3 - Making the Model

Part 2 - Making Plans

Part 1 - Then and Now

In the last two articles, I’ve covered what half hulls are and how to make plans for one from pictures of your boat. With the help of last issue’s article, I will now cover how to make a model from the plans you drew up. You DID make the plans, didn’t you?

There are two ways for the average boat owner to make their half hull model, either from a solid block of wood or built up from ribs and stringers and then planked. Each has its advantages and I’ll cover them both. Note: I chose to make the model in these illustrations using the built up style.

Preliminaries

The first step, no matter which method you chose, is to prepare templates. These can be traced from your plans by using carbon paper. I got a real surprise when I went to the office supply store to buy some carbon paper. It seems, in this age of NCR paper and computers, to be a rare thing. The only package I could find had a hundred sheets and was expensive, but I did find more reasonable quantities and prices at the local craft store. I used regular poster board for the templates themselves.

You are going to need a template of the side (or profile) view of the boat as well as templates for all the stations or cross-sections on the plan. If you are making a block model, these section templates will be cut out of a poster board square a couple of inches larger than the section.

If you are making a block model, these section templates will be cut out of a poster board square a couple of inches larger than the section.

For a built up model, these section templates will be the shape of the section itself

The size of the section templates for the built up model will need to be smaller than the drawing size by the thickness of the backbone and the planking.

Finally, if making a block model, you will also need a template for the top or plan view of the hull. Mark all the templates with the appropriate station and centerlines. Now let’s get on to the models themselves.

Block Model

Most original models were built from blocks of wood. Those blocks could be solid chunks of wood or blocks glued up from individual layers. If you’re planning on using this method, select good straight-grained woods. Basswood is good as are mahogany or pine. My all-time favorite carving wood is sugar pine, but that’s getting hard to find and expensive. Avoid curly grain or knotty wood as it makes smooth carving difficult.

Block model

Basswood carving blocks or a variety of different thicknesses of wood can be ordered online from several sources (try: www.woodnshop.com or www.rockler.com). Prices are a little higher than local stores, but availability and quality are usually better.

The layers of wood can be glued and clamped together with any good carpenters glue and then left until the glue is completely dry. Smooth up the surfaces of the block and draw the station lines on it. Trace the top outline and the side outline onto the block. The quickest way to proceed is to cut the block along these lines with a bandsaw. If you don’t have one, you can try a coping saw or saber saw with a long blade.

Cut the top outline first and then tape the cut-off piece back on with masking tape. This will allow the block to sit level on the bandsaw to cut the side outline. Once these two cuts are made, retrace the station lines around the block. You can now start carving away the excess wood, testing the shape of the hull with the templates you previously made.

I use a variety of tools for this kind of carving. A small block plane, gouges of various sizes, chisels and small drawknives used in violin making work best for me. I purchased most of these tools online or at specialty hardware stores. Be sure and keep the cutting edges as sharp as possible for quick and accurate work. I use two grades of Arkansas sharpening stones and then polish the cutting edges with Tripoli compound on a leather strap. One drawback of this model making method is the need for good woodworking tools.

Keep carving the hull while checking with the templates. Feel the hull with your fingertips as you carve to keep the lines of the hull smooth and flowing. Once the block is shaped to the templates, you can sand the hull and prepare it for finishing. Be sure to keep the sharp edges of the hull crisp, don’t sand them round. If you carved it accurately, minimal sanding should be needed. The hull is then ready for finishing.

Built-up Model

I recommend the built-up method if you don’t have access to a variety of power or carving tools. Simple Exacto knives, found at any craft store, work fine. I used 1/4” inch hard balsa wood for the backbone on this model. A short length of 3/4” square pine was glued on this backbone to reinforce the balsa and to accept the screws that will mount the model to the backboard.

I cut the stations or frames out of sheet balsa and notched them to fit around the pine strip. Notches were cut in the top corner and at the chine line of the stations to accept strips of balsa. Work went quickly as I was using 5-minute epoxy to glue the parts in place.

I was using 5-minute epoxy to glue the parts in place.

Once the stations are glued to the backbone and the initial stringers are in place, it is time to plank the hull. In my case, the original boat was sheathed in plywood, so it was a simple matter to use 1/32” plywood for the hull planking. I first made patterns, using poster board, before cutting the plywood. I was able to cut and trim the plywood with standard scissors. If your model has a rounded hull, use smaller strips of balsa as planking. These can be glued edge to edge as well as to the stations and will follow the curve of the hull. Once the planking is finished, sand the hull and fill any imperfections with wood filler.

Finishing Touches

By now, either model is ready for the final steps. If your boat has spray rails, skegs, chine runners or gunnel details you wish to add, now is the time

If your boat has spray rails, skegs, chine runners or gunnel details you wish to add, now is the time.

On my model, I used square strips of basswood for these details. Rubber bands and pins were used to hold these in place. Crazy Glue or CA (cyanoacrylate) glue works well here.

The final finish is up to you. The model can be painted to match the real boat or finished natural. I used spray enamel from the local home improvement store to finish the hull. The boot stripe is a narrow roll of boot stripe tape from the local boat store.

The last part of the model is the backboard. There are a multitude of woods to choose from. Mahogany, cherry or oak are great for backboards that are finished natural. Poplar or pine is fine if you want to paint the backboard. Allow several inches of backboard all around the model so it doesn’t appear crowded. The edges of the board can be left square, chamfered or, as I did, routed with a fancy bit in a router.

The edges of the board can be left square, chamfered or, as I did, routed with a fancy bit in a router.

The model is then screwed to the backboard. Make sure the model sits as it would on the water, with its waterline parallel to the edge of the board. The last touch is an engraved brass plaque with the boat’s name or model on it. You can have these made at one of the engraving kiosks at the local mall.

Well there you have it.

Well there you have it.

Making a representative half hull model of your boat isn’t difficult. I hope these articles are enough to encourage you to make your own model. Sign and date the back of yours, you never know when you may become a famous half hull maker!

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