Wainlode

I broadly agree, although the bigger the prop the greater the amount of energy required to push it. The other important factor is pitch - too much and it will add a greater strain at the gearbox (think trying to pull away in third gear). The saving grace is that canal boats operate at relatively low RPMs. This one may be too large for a narrowboat.

Just want to say thanks for the input, especially from Mike. Props are a very complicated subject! One thing at a time for me.

Hi again thanks for the replies, most helpful. I have heard of Mitsubishi in connection with Thorneycroft, and since they are Japanese I immediately think 'reliable'. Agree? (I know its a BMC forum)! Also one other question: are all BMCs marinised by Thorneycroft, or are there any marinisation brands worth steering clear of? And finally, knowing I am at risk of asking too many questions...any gearboxes to avoid / prefer?

Hi all, I'm new to this forum and this is my first post. Any opinions happily received. I am speculating on a couple of boats, one of which has an unspecified Thorneycroft engine in the description. I assume it will be a BMC of some sort. A thought crossed my mind: what was the nicest BMC engine? Perhaps in terms of power output, fuel consumption, ease of maintenance, general reliability or perhaps more importantly here in 2019, the availability of spares? Maybe the better question is are there any to avoid? Thanks in advance.