2004 – Page 10 – The Scrumble Project

Stored under the starboard bridge deck half – 4mm hardwood ply panels for the port sacrificial keel, cut out when we did the set for the starboard hull.

All the port hull panels stacked in order (position and order is paramount in minimal space) as lifting the large panels into the frames must be as simple as possible, so that we can proceed with just the two of us.

All panels except the bridge deck laid down to prepare the edges to be taped and any other bits I will go into as this post proceeds.

Edit by Tom 12 Feb 2006

As we discovered later, at this time it is important that the bridgedeck panel is reinforced with the composite under deck beams.

This is the stern of the inside sheer panel which turned out to be 100mm short on the upper rear edge, the forward part of which joins with the rear of the bridge deck. On the starboard hull we added a 100mm after the hull was taped up in the frames.

On the port we wished to have the panel correct to start the hull, so we thought if we reconstitute the routed cut it would be a better result. The following images show the process.

Black plastic over a rigid piece of ply etc to form a very flat surface, cut away the peel ply, sand the Techniglue green bits at the Z joins for a smooth “keyed’ surface then glue (silica and epoxy) the pieces in place. The pieces are then taped with 140mm weft triax. Do one side and then when cured turn over and do the other. The edge to be trimmed is just at the edge of the tape.

If one looks closely the filled router slots under glass can be seen on the trimmed and prepared panel standing agaist the outside sheer.

Centre are the four bilge panels which are approx 100mm short if a smoother line to the water is to be achieved at the transom. We added 100mm to these and trimmed them in the starboard hull once it was upside down. This time on the port hull, we wanted it done before building and then just trim to shape prior to turn over. The following images describe the “cut and shut” method of increasing this hull to 13.5m to match the other as described on 28 Feb 2004.

I have to make it clear here that these two differences in the panels were due to the design files and along with the slightly narrower forward bulkheads described on the 19 Jan 2004 would have been “weeded out” of Bob’s files long before this entry. The rest of the panels fit very well together with only a little expected torture required with bilge and chamfer panels at the bow.

The piece is butted up with glue and the taped on one side, cured, the other side taped, then when cured shaped with a emery disc on the 115mm grinder.

This tool is very useful for shaping glass and trimming quickly, but its very dangerous in this cut down, unguarded, racing model so great care is required the edge will cut through eglass, and the core in this case balsa and your flesh in a flash as I unfortunately learned through experience.

Glue shown at the join protruding before trimming.

The finished extension.

This shows a sanded Techniglue Z joint alongside an unsanded item. We took all the peel ply off the inside of each bilge panel and the required amount from the other panels at this stage and sanded all the techniglue. Sanding is much easier on a flat panel mounted on the “workmate” trestle stands at waist height.

It is worth mentioning and showing that when cutting out the panels after making all the Z joints at the start, that if care is taken and a little grinding done to the cut tabs, the panels fit together in the frames superbly. If however a tab is left protruding it will cause untold fitting grief.

Slightly concave is better than convex (leaving a little of the tab on), however……

… do not cut too much as this occurs and filling required with fillet mixture, in this case not until the hull is turned and filleting is being done prior to exterior taping.