The Coverup

Don cutting out one of the garboards

 

Once the planks were glued up, they were cut to shape using the full-size patterns. We used three different methods to attach the planks. The garboards were screwed into the bottom panel using temporary screws, pre-drilled and driven in at an angle. With the middle planks we were able to use plywood clamps and wedges. This method is excellent for glued plywood lapstrake planking but unfortunately was not possible for fastenening the garboards due to their width. Nor was this method suitable for the sheerstrakes because the sheerclamp was in the way. To attach them, we used temporary screws along the sheer clamp. At the landing, a batten was fastened with screws and spacer blocks to the frames, stem and transom. Wedges were then slipped in between the batten and the plank to apply pressure.

 

Temporary screws fasten the garboard

Plywood clamps with wedges fasten the middle plank

A batten with wedges holds the sheerstrake tight to the middle plank

Doggone Scarfs

Pattern for the second plank

Once the full size plank patterns are made, the marine ply is cut into strips, 16” for garboards and 8” for the other two planks. The patterns are layed over top of the strips to determine the angles for the dog-leg scarfs. A power plane or jack plane is used to take off the bulk of the wood, followed by a sharp low-angle block plane. Planing the scarfs to a feather edge, without tearing out, is especially difficult with the paper-thin outer veneers on today’s marine plywood.

Small finishing nails are driven through the joints on each side to keep the pieces aligned when clamping. The garboards and middle planks required only one joint each but the sheerstrakes needed two scarfs each to make up the required length.

Channel blocks, the width of the scarf, are clamped top and bottom giving even pressure on both sides of the joint and they also allow the alignment nails to stay in place while clamping.

Ready for gluing. Note: holes for registration nails.

Scarf joint clamped using channels blocks

Dog legs

 

 

Bottoms Up

Bottom panel glued and fastened with temporary screws

The bottom panel is the easiest of the planking to install. After fairing, the 2′ x 13′ scarfed panel is laid on top of the setup and the outer edges of the frames, molds, stem and transom are marked. Using a batten, line up the marks, scribe the line and cut out with a jig saw. A few temporary screws hold it in place while the epoxy sets. Next, the edges are planed where the garboard planks will be fastened.

Chris uses a batten to scribe the shape of the bottom panel

Don planes the bevel on the edge of the bottom panel

Clamping the Clamp

The last thing to be done before the planking starts is to fit the sheerclamps (inner gunnels). Usually they are attached after the hull is turned over, however, with dories they are notched into the frames and fastened to the stem and transom. Holding them in place while the epoxy sets is a bit of a challenge especially at the ends where they have a tendency to twist. At the bow we used temporary screws with a “V” clamping block and at the transom we clamped a piece of wood to the outside of the sheerclamp which was then screwed into the side of the transom.

Sheerclamp notched into frame (left) and clamping “V” block at stem

Sheerclamp held in place at transom

 

On the Level

 

Molds being setup on building frame

Two tools that don’t see a lot of use in boatbuilding are a carpenter’s level and square. The one exception is when setting up the building frame and attaching the molds, frames, stem and transom. Ensuring the 16′ building frame rails are straight is a challenge using solid wood so we cut 5/8″ plywood into 3-3/4″ strips and laminated them together. The frame is 30″ wide and 21″ high, making it a comfortable to work on the boat but also gave us enough room to crawl under if necessary.

Frame #6 in position

The tombstone dory transom and laminated inner stem

Made to Measure

Before buying the marine plywood, the most expensive item in building these boats, we had to determine how many 4′ x 8′ sheets we required. A materials list comes with the plans but the plywood specified is 5′ wide which is not available here. By building a simple scale model using cardboard and bristol board we were able to calculate the widths for each plank and the number of strips we could get from each sheet of plywood.

For the two boats:
The bottom panels: two 12mm sheets ripped into four pieces, 2′ x 8′
The garboards: three 9mm sheets ripped into 16″ wide strips
The middle and sheerstrakes: three 6mm sheets ripped into 8″ wide strips

 

 

 

Framed

The frames are an integral part of dory construction. Amberjack plans call for two frames, one at station #2 and the other at #4. We have added a third frame at station #6 for additional strength and for fastening a seat riser. This will allow the thwarts to positioned anywhere along the riser. We decided to laminate the frames, including knees, after reading of other builders having solid wood frames split when fastening the shearstrake. No doubt naturally-grown knees would solve that problem but the laminated frames should just as strong.

2″ x 3/16″ Douglas Fir strips ready for gluing

Clamping setup

Frame patterns incorporating the knees

Each frame is cut down the centre to produce two identical halves

Completed set of frames for one boat