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Prop size for a 225?

M

metal-chicken

Regular Contributor
Now I have a working gearbox I'm looking at the prop. Our boat is a Boston Whaler 210 with bottom paint and our total weight (inc people and fuel) is about 5000lbs. Currently it's got a 4 blade Trophy Plus prop with a 21" pitch and I can get about 5600 rpm at WOT - but the hole shot doesn't seem good at all.
From limited research a 21" pitch seems too much for this boat as BW ship the boats with 17 or 19" props. Does it seem right to go to a 19" prop or should I look lower still?
 
Are you running a deep V or modified V hull? What's your beam?

IMO it looks like you are pitched way too high. I'm running a 14.25 X 15 SS three blade on a 25 ft. C-Hawk with a modified V hull and 9.5 ft. beam (just like the Parker 25 XL.) Fully loaded, it weighs about 6000 lbs. Even with that, the hole shot is a bit sluggish.

Your goal of course is to be at about 6000 rpm at WOT in flat water. In the past, I've gone to a local marine shop and asked to borrow different props that they invariably have laying around in order to find the best set up.

Hopefully, others will jump in that have a 225 mounted on a boat similar to yours.
 
It's not particularly a deep v as you can hopefully see from this pic - it's a 8.5ft beam. We don't really have access to props to try unfortunately so we need to get this right if we're buying. I'm thinking a 17" pitch might be better than a 19.
6067.jpg

I was able to do another WOT run today in flat water with just me on board and about 400lbs of fuel, in a slight following wind I got 5200rpm and 43mph on the gps - so possibly worse than I originally thought. Theoretically I could easily lose 4" of pitch.

With 6 people on board it took about 15 seconds to get up on the plane and the engine wouldn't get above 4000 revs until it did so.

edit: Oh and engine height isn't an issue as it's on a hydraulic jack plate and we def get the cav plate out of the water.
 
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Can't tell for sure, but that looks like a modified V.

Anti-cavitation plate should be riding just on the surface of the water coming off the transom at WOT on plane. Then play with the trim to max rpm's.

I'm guessing here, but I would suggest a prop with a 14.5 to 15" diameter and a 17" pitch.

Over the years I've had good luck buying and selling props on eBay. There are some good bargains to be had there from individual private sellers. Just make sure you have a good return agreement. Some folks sell props that have a spun hub and don't even know it.
 
Thanks guys. I should have added that top speed is definitely not the priority - the boat will be fairly well loaded and quite probably pulling something. Long cruises at a fixed speed are rarely undertaken.
 
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