Rinker 265 prop size reduction for the river Thames......opinions?

ajj001

OK, so I have a '95 Rinker 265 V with a 5.7l block on board and a Bravo 2 stern drive. It is moored on the river Thames where we have a speed limit of 8knots (don't laugh!) in the non-tidal reach (below the last lock at Teddington, it is considered tidal, and the speed limit is higher). The big block is clearly over the top for power and barely gets over 1,000 rpm here. So I am a bit concerned about the plugs fowling up and the engine not benefitting from the odd power surge (for which it is clearly designed). Speaking to another boat owner, they suggested putting on a smaller prop, or one with a different pitch, so that the engine worked harder. Does anyone see a flaw in this?

Handymans342

Yes, because the day that you go up to full speed with the wrong prop, goodbye motor. How far would you have to travel to get up to full speed?

ajj001

Handymans342 thanks for feedback. I guess this particular boat won't be out of the Thames for the foreseeable future so unlikely to go to full throttle but I supppse you"re saying that even if I pump it fully open just, say, to warm her up, the lack of prop resistance puts the engine at risk. Maybe I could put some kind of physical restraint on the throttle cable to prevent it going all the way.