For more power add more engines but the gain will be small. Better solution is the medium engine as the bigger brother of Pegasus S, the Pegasus MPV offers.
I don't know of a people finding sensor. There is one to recognize players but only in a small area.

Whatever I was doing last night I didn't manage to do this evening - ran 20KM virtually flat out with a load. Think I've got to have held the engine starter with the throttle too low at a guess? Out of interest would it be possible to up the power on this? Also are there sensor for finding people by any chance? (don't even know if that exists?).

Thanks - am so new at the game I'm expecting that I am just breaking stuff if that makes sense. Jumped in the boat. Was a bit pushed for time so banged the throttle right up - was at night so flipped the lights on and am taking a guess - it doesn't charge as well at top speed? Am figuring there is an altenator in there somewhere like you would have in a car (e.g. engine on = charge to the battery). Either way, was caning it around and did the battery in about 25 mins I'd say. Am sure I did something noobish to break it but I'm sure it was the battery and not petrol. Will have another go and try and break it again ;-)

Well the designe is some updates old but I just tested it and had no issues with the battery while driving. The battery does drain if the engine is out or running on very low rps and lights are on. But to completely run down the battery it needs to sit around that way at least 30-60 minutes.
Thats what the battery switch is for. Right now I can not reproduce this battery failure. Sure it was the battery not fuel and you did not damage the boat?
Maybe you tried to start the boat and throttle was to low for the engine to run. If you hold the engine starter for some time and engine does not start, THAT drains battery fast. If that is the case most of the time people forgott to set throttle up after shutting down the engine.

Used it to complete my first mission (did run the battery down though ).