Building the Fire Fighter 26 Gas Rigger
From Tom Moorhouse
Over the winter months we will be building a gas rigger
Part 2
Finishing the Tub and Building the rear Sponsons
Fitting the top bottom and doubler pieces to the engine and radio hatch, top and bottom skins and starting to glue the sponsons up
I pre cut the top and bottom from 1/8 5 ply I left both 1/6 oversize to allow final sanding.
With the tub still in the jig I fitted the top first, I have seen many ways to do this but I think my was is better, I cut several pieces of 10m ply marking out and marking where I could screw them to my base. After gluing up the top I fixed the position and screwed down the blocks pulling down the top and also pulling the tub down square to the jig, leaving to set for 24 hours, Just make sure if you are doing this on the best dining table you do not use to long screw as they do not like holes in the table, I put the radio hatch lip on by cutting a piece of 1/8 ply from the bottom inside and using a compass drew a line ¼ in from the opening in the top, this is then glued in from the bottom and clamped with finger clamps.
The bottom was glued up and wider blocks screwed down either side of the tub pulling the bottom and the tub square into the jig leaving 24 hours in the jig.
The tub has been removed and only needs the nose piece and a light sanding, for the nose piece I have chosen English oak.
You need to set a lip for the engine cowl to rest on, I just use 2 strips down each side, the back of the engine bay need to have a support for the cowl locks this is just a piece of ½ ply glued in as a doubler the last piece to go on is the bottom, this is a piece of 1/8 4 ply and is attached by clamping down to the base board.
Key point is to attach as many pieces as you can without removing from the Jig and keep the weight as low as you can.
Building the Rear sponsons
The following parts are needed to sheet the rear sponsons:
2 - 1/8” plywood Sponsons tops.
1 - 1/8” plywood sponson back.
2 - 1/8” plywood sponson bottoms.
2 - 1/8” plywood sponson out sides.
2 - sponson cores.
Sand down the sponson cores to make everything nice and flat. Make sure you don’t sand too much.
The sponson back should be square with the sponson inside. Attach the sponson back.
Glue the templates to some cardboard before you cut them out to make them more ridged.
Holding the correct template on the bottom of your sponson examine the angle you have. Determine
what you need to sand to match the template and sand it until they match. You might find it easier to
measure the bottom angle if you hold the sponson bottom in place while checking the angle.
Attach the sponson bottoms when you have the bottom angles matching the templates.
With a sanding block sand the sponson top so that it is nice and square to the sponson inside. Attach
the sponson top
Shape the sponson outside. The sponson core needs to be shaped before attaching the sponson
outside. Use a knife to rough cut off the majority of the foam. Use a sanding block to sand the foam
nice and smooth up to the wood. You also need to sand enough of the wood so that it is angled for the
sponson outside to be attached properly. Take your time to make sure all the parts fit nice and tight to the core.
. Be sure to keep all bottom angles sharp. Do not round any corners as it will slow your boat down.
I left each part of the sponson to completely cure before continuing, I set a piece of angle down on my flat work surface and using my template used washers under the angle to obtain the correct angle to the work surface, I glued a piece of 4”sand paper down, by sanding the cores holding it against the allow I could sand an exact angle.
After the last piece was glued to the cores I set both aside for 24 hours to fully cure before sanding.
