Originally Posted by Happy Shopper
I don't want to increase the top speed of my boat, with just myself on it it will just about make it to 30 knts but it's screaming at WOT as soon as you add another adult it immediatly you are looking at about 25 knts.
It would be nice to be cruising at around 25 knts without the engine screaming. Like my friend said you wouldnt drive your car around at 6000rpm constantly.
Am I asking too much? My boat is a ~5.5m Avon adventure (I think!)
The engine is only a few years old and I recall the previous owner changing the prop before when he put the new engine on. The boat did have a 75 suzuki previoulsy but that was stolen.
Would love to know your thoughts on this
Is there any measurements I can take of the current prop to get an idea of what I have?
You don't want to do this. The boat is underpowered, pretty plain and simple. With 75 ponies it was underpowered, 60 is just even worse.
If you want to cruise at 25hp, with a cruising rpm of about 38-4200 (typical), you need a bigger engine. Like 100hp minimum.
Swapping the prop will only make you over-propped.