Over the last few months I have been rowing my Acorn 15 regularly because I enjoy it and I need the exercise. My Acorn 15 rowing boat has a fixed rowing position and I decided that it would be a good idea to try rowing with a sliding seat to get a more complete workout. One option would have been to modify the Acorn 15 by fitting a sliding seat. I wasn't keen on doing this because I didn't want to spoil the look of the Acorn 15. It would also have been a compromise solution.

While these ideas were going round in my head I came across the photo below taken by my friend and fellow member of the Wooden Boat Association of Queensland Ian Primrose.

The photo is of a Classic Derwent Skiff designed by Allan Witt of a company called Row and Sail based in Tasmania.

I liked the appearance of this boat which is configured with a sliding seat as shown. The rowing position can be moved forward and an additional seat added for a passenger if desired.

This version of the Derwent Skiff is 5.5 metres (18 feet) long and should weigh around 38 kg. This is less than half the weight of my Acorn 15.




Wednesday, 7 March 2018

The Kit Arrives. Inner Stem, Keel and Outriggers

The kit arrived at the transport company's depot and I collected it. Here it is.


Inside the pack were four and a half sheets of 6mm ply. Each sheet had been CNC cut with the pieces held in the sheet with short tabs. Here are the four full sheets - you can enlarge the photos by double clicking on them.


First job was to laminate the 3 layers of 6mm ply that form the inner stem. Where the pieces join there is aan individual puzzle joint so the pieces can only be assembled in the correct order. Here they are wrapped around the mold with plastic to stop them sticking to the mold and plenty of clamps.


While the epoxy was setting on the stem I laminated the five pieces that make up one of the outrigger arms. There are 3 pieces of 6mm ply with outer layers of 4mm solid timber. The laminations are kept in place by the bolt at the left hand end of the jig. With this pulled tight the clamps are applied progressively to the right.


Here is the complete lamination held in  a pipe clamp to stop (or reduce) springback until the epoxy is hard.


The rest of the keel is made up of 2 layers of 6mm ply put together in sections and glued with epoxy. No photo of that but essentially the same as the stem. Once the stem and keel are glued (and screwed to the mold) the edges have to be bevelled so the first plank can be glued to them. I did this with a Ryobi cordless planer fitted with an arm the outside of which is in line with the base of the plane.By running the arm along the lower stringer (where the plank will sit the plane is held at the correct angle for the bevel.


Here are the pair of outrigger arms after some initial cleanup. When in the boat the oarlocks will be in the hole at the rounded end, the far ends are joined together at the keel and the mid point is bolted to the gunwale.

Next step is to make the transom, fit it to the mold and glue it to the end of the inner keel. While that glue is setting the aft end of the garboard planks has to be prepared.







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