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[Bob K]

HMS Skirmisher refit

After almost a year of successful and uneventful sailing my HMS Skirmisher is in dry dock for an urgent major refit.
  HMS Skirmisher
Disaster struck last month when it almost sunk after a freak gust of wind swamped it with three inch waves.   
See “My First Working Submarine” on Mayhem . . .
http://www.modelboatmayhem.co.uk/forum/index.php?topic=36180.0

OK, it was a rebuild that came with drop in decks.  They had never caused problems before, but even 2” freeboard aft can be overwhelmed on a sheltered boating lake. 
Some redesign was urgently required, not made easier by the original construction. 

The plan now was to rework the deck joins to make them as waterproof as possible, fit watertight chambers for additional buoyancy, a bilge pump to clear water ingress and to gain more time to reach safety, plus necessary rework of waterlogged electrics. 

View with centre and rear decks removed: 
    Interior view

In the destroyer I built afterwards I incorporated rebated access hatches with magnetic catches, and a series of bulkheads to limit water ingress.  No water problems.  However, retro fitting these on Skirmisher (above photo) was not an option.

First up were the electrics.  A rewire was needed, plus means to extend the wiring to include bilge pump, Rx and lights.  It was a good opportunity to fit an ACTion P94 combined ESC’s and mixer as this had given superb manoeuvrability and ease of set up in my destroyer.  The P94 was a tight fit between motors and battery compartment and I had to cut down the heatsinks fins by 5mm.
Weight was an issue as the big SLA 6V battery is the total ballast.  The P94 at 115gm replaced two Mtroniks Marine 20’s at 55 gm each, then 36 gm for the pump and 26 gm for the controller.
    P94.  2 x ESC's & Mixer


Next the bilge pump and pump controller from Hunter systems.  The pump was mounted into a ply base so that the pump inlet sat close to the lowest point in the hull.  The pump controller mounted nicely between the P94 fins. 
     Bilge Pump system


Motors and P94 wired in.  There was a lot of extra wiring to add.  The Rx needed a separate power lead as the P94 has no BEC, power for the pump control box, and also for the new navigation lights.  A lot of dissimilar wire sizes involved so I made up a small power distribution board.
     Rx and Power Distribution


Next Instalments will be:

• Retro building in watertight chambers
• Clear acrylic sealed underdecks with magnetic catches.
• Fitting navigation lights.

[Bob K]

Under-deck Sealing

With the updated electrics rewired and commissioned the next stage was sealing under the two lift-out deck assemblies.  Due to existing construction it was not possible to retro fit waterproof hatches and bulkheads as I had built into my destroyer.

Method used here was making a close fitting 0.8mm thick clear rigid acrylic under-deck, with a small amount of RTV sealant on the edges, held between seven pairs of 6mm neodymium magnets.  Keeps wet out, but still readily removable.  The most difficult part was shaving 1mm from the underside of a vulnerably detailed deck / superstructure assembly.

   Aft deck panel

Outlet tube from the bilge pump looped above deck height utilising a recess in superstructure, then exiting as a dummy porthole so as not to be too visually intrusive.

Centre section to be done in similar method, but cutting in coaming strips around the access rectangle for Rx, switch, sockets and distribution board.

[Armo61]

Great work Bob K
Charles