is a hidden cock within the diesel supply an appropriate tool to immobilze the boat, when e.g. leaving it out of sight for 1-2 hours? want to save the costs for electronic devices. chris.
Chris, welcome.
It could work, but it's not without risks if you forget to turn it on again, and then start engine.
Air could be sucked in through weak seals, meaning bleed fuel system.
Not a good idea if you have just left pontoon.
You would have to be very diciplined about turning it on and off.
Has your injector pump got an electrically operated fuel shutoff, or is it cable?
If electric, why not rig a hidden on/off switch to that.
I'm not so sure. There would be enough fuel in the filters and pipes to give your thief maybe 10 minutes motoring away, the engine cuts ... then what? Could be nasty!
If you don't think an electric cutoff is secure enough (it is after all pretty easy to jump start a diesel), maybe mechanically immobilising the gear might be an idea?