Scarab 16 beams part 3

I painted the beams to match the rest of the boat using 2 pack epoxy primer and Jotun Imperite (Home Yellow).

The aluminium folding struts were cut by a local business using a water jet cutter. Then they were painted using etch primer and Jotun Imperite.

Scarab 16 beams part 2

Layers of glass was added making sure the moulding was not allowed to get too hot.

The beam mould has the pivot holes marked on the outside. Before the moulding is removed small holes were drilled and the edges of the beam was trimmed. The holes were later drilled to 16mm.

Scarab 16 beams part 1

The beams are similar to The Scarab 18 only smaller. The beams are attached to the beam support which anchored in the main hull. The beam support pictured is the Scarab 18.

I made a plug for the beam. The plug was painted and waxed several times to allow the mould to separate easily from the plug.

Then a mould was made using tooling gel. Most of our boats have female moulds made from plywood or form ply. But I always have my eye on the next boat and tooling gel is very tough. It will last through several boats.

Scarab 16 floats part 3

The floats were painted with Jotun Imperite (Homebush yellow) sprayed with a gravity gun 1.4 nozzle. 

After the paint hardened the area to be masked was marked out using masking tape. I used KiwiGrip non-skid (white). This non-skid was easy to apply and clean up (water based). The paint was applied with a spatula and brush to the desired thickness then rolled with a special textured roller. It’s the best non-skid I have used.

Scarab 16 float part 2

The deck was made from laminated foam. The top layer of glass was cut using a diamond blade in a circular saw. This allows the foam to bend into a fair shape. Bog was applied in the cracks and once sanded glass was laminated over the deck. The edges were rounded off and taped to the side panel.

There was a problem how to bolt the beams to the floats and the easy way was by using inspection ports to allow access to the bolts. Because there was a bulkhead under the beam it would have required 2 ports for each beam. I didn’t want to have 4 ports on each float so I decided to use the float as a plug and make a split mould of the floats. Instead of the bulkhead there was two ring frames where the beams are attached.

Probably not one of my smarter decisions but it would allow me to build another boat with a lot less work. So, I could justify my decision.

Scarab 16 float part 1

The building frame longitudes and bulkheads for the floats (MDF and plywood) was cut out and assembled. The frame slots together and is self-aligning. The building frame bulkheads were rounded on the bilge panel which is different to the original boat which has chines. The side panel and the bottom panel were attached using gyprock screws.

Then the bilge panel was strip planked using laminated foam strips. Each was screwed to the building frame and glued to the one below. Then glass was laminated over the bilge and bottom panel.

The hull was taken off the building frame and glass was applied over the strip plank area.

Scarab 16 foam sandwich panels.

The boat is built using foam sandwich using Gurit 10mm foam. We have always used Klegecell in the past but this is what was available from our supplier and it worked well.

The panels are made by joining the foam sheets together the full length of the boat and then covering with glass. Peel ply over the glass makes a good surface to loft the panels.

 All the dimensions were supplied on the plans. I used panel pins on the points between the stations and a thin piece of plywood or a sail batten bent around the nails to draw the lines. All the hull panels are the same as on the original Scarab except the bilge panels on the main hull and floats, these panels were strip planked. The panels were all cut using a jig saw.

Scarab 16 Design Brief

This boat will be an off the beach trimaran. The boat will be built using the plans for the Scarab 16 but with a few alterations. There will be no cabin which will leave a large cockpit that will allow up to three people to sail it in comfort. The floats are high volume as are the original boat but the beams will be bolted to the deck of the floats instead of being glued inside.

The folding system will be similar to the Scarab 18. The beams are mostly the same only smaller and the aluminium struts are smaller. It will be easy to fold the boat in the water or on a trailer. Once opened the beams will be anchored with a bolt through the aluminium strut.

The boat will have a main sail and jib with a prodder to use a schreecher.

The original plan calls for chines on the main hull and the floats. I will round off the bilge panel on both.

Instead of having pivoting centreboards in the floats as the original Scarab I will have a dagger board set in the floor of the cockpit

The transom will be open to allow water to drain quickly if some comes aboard.

At the moment I don’t plan having an outboard but there is space on the transom to mount a small one.

Scarab 16 folding trimaran

The Scarab 16 folding trimaran is a small trimaran for small family and over night stays. I am building a Scarab 16 with no cabin and a larger cockpit for weekend racing or fun out with the family.