Well the sub has progressed nicely but, as always, has taken a lot more time than was anticipated.
I now have all the workings installed and tested after a lot of messing around and fiddling. I wanted to make sure that the deck had the minimum of openings so I have arranged for one main access through the deck in way of the centre section around the tower. Either end of the deck I am going to glue in place with the far aft steel section being the only other removable piece to allow access to the rudders.
This required the motors to be in the centre section and so the tubes were 10" long with 12" long shafts. As these were 4mm tubes with 2mm shafts the fit had to be spot on as any slight misalignment would cause interference. I also checked with the shaft manufacturer what lubrication I should use and he assured me that silicone grease would do the job. I had asked as I was concerned that such small shafts, so long and connected to very small motors might be a bit of a struggle.
As it happens I was correct and after installing the shafts and filling one with grease I discovered there was no way the motor was going to turn it. So all the grease had to be removed, remember pipe cleaners?, and I retried with light oil. It worked fine but leaked from the end so I realised I needed an oiling tube and grease on the bearings.
The pictures show the set up as it became with two oiler tubes fitted to the shafts, not easy after they were installed, and the motor and coupling set up. The motors are mounted in a piece of wood, drilled with two 16mm holes on 31mm centres then cut in half to form a clamp. This holds the motors nicely and the only concern I am left with is the very poor quality couplings which are so far out of balance as to cause vibration. They will be replaced in the future but will do for now.
The rest of the installation includes a micro receiver from Hightec, a nice solid state 1 amp speed controller with switch and a battery pack made from one of my old 9.6 volt aircraft packs. I removed two of the cells to make a 7.2 volt pack which fit very nicely in the front of the boat.
All this lot was installed in a tray manufactured from plasticard on the workbench, before fitting into the hull.
Ballast was made from lead sheet cut into thin strips, which fit into the keel very neatly and wider lead strips laid over the top of those. All the ballast was secured in place by pouring resin over the top of it in stages to reduce the heat build up when curing.
The pictures show the various components as fitted in the tray and after the final sea trials in the domestic test tank.
The hull has been sprayed with Tamiya acrylic spray tins which proved to give a superb finish. The only problem seems to be that there is not a great deal in each tin, which very nearly caught me out. The dark grey has had three coats and the tin was empty when I finished. I hope I will have enough of the lighter grey for the tower and deck fittings and I have a pot of very dark grey for the decks.
Now all I have to do is finish the model!