Replacement props

[thisismurph]

Hi
I'm looking to replace two damaged props on a 1993 340 Santego. 18 x 23 four blade 1 and 3/8 shaft Would love to find something used. Do I need to have the exact same prop or is there some wiggle room
Thanks!!

[bud37]

Welcome to the forum.......

Source of the post Do I need to have the exact same prop or is there some wiggle room
Thanks!!

This will really depend on how your boat was running before the damage......did it get on plane smoothly and relatively quickly without drama, what was your max (wot) rpm on plane. If you can lay that out , a good prop shop can help you make a qualified decision.
A small change in prop sizing may not have too much effect but if you are at one end of the range or the other for your boat as it is now ( loading etc ) it can make quite a difference to running and efficiency.

[Alanna Mo Cree]

I had a damaged prop fixed on a previous boat. I hit a rock and tore a big chunk out of it. They were able to fix it up as good as new for pretty reasonable from what I remember. That was quite a few years ago.

[Viper]

Welcome aboard. Ya I'd get them looked at by a prop machine shop first. A reputable shop won't charge you for assessing and giving you an estimate for repair.

[MyPleasure]

For myself, I would want to know what max RPM is for the engines on your boat? Did the engines reach that RPM with the boat loaded up with fuel and water? A lot of boaters over prop their boats to get more speed at a lower RPM, but you’re actually putting more load on your engine with the oversized props.
We had a 36 Uniflite with 350 Crusaders, when we bought the boat, it would only run up to 3500 RPM, and get about 18 knots with zero vacuum, (some previous owner had installed vacuum gauges on both motors).The props were 18” X 22” 3 blade with 1 1/2” shafts. I got a set of 4 blade props from a prop shop in Anacortes that was going out of business, so I got a great deal on them.
I had a great conversation with a local prop shop, and we determined that we wanted to get the engines up to max 4200-4400RPM at WOT. They figured out that the best diameter and pitch with the 4 blade props would be 16” X 17”, which worked out perfect. The boat max RPM now was 4300 RPM, speed was now 26 knots, and I had 5” of vacuum at WOT.
While cruising at the same 8 knots, the RPM was about 200 more, but the engines had 10” of vacuum, and got better fuel mileage because the engines weren’t working so hard.
if you’re not getting full RPM out of an engine, even when fully loaded, then you’re working it too hard at any RPM.
Just my opinion of course

[buster53]

Yep, take them to a good prop shop first. You’d be surprised at what they can do with damaged props.