What Propeller for 2400 SC

[moselpirat]

Hey Experts,

I need your help. We are having on our Maxum 2400SC right now the following Propeller: SOLAS 9531-143-17
The following engine is installed: Mercruiser V8 with 220 HP

We are cruising only on a quiet river: Mosel in Luxembourg and Germany. It feels somehow that the Boat could move better.

Do you think it is the right Propeller or do you have any recommendations?

Thank you in advance.

[mmwjr]

I would try seeing what the Quicksiler online prop calculator suggests.

[shrew]

Originally Posted by mmwjr

I would try seeing what the Quicksiler online prop calculator suggests.

Agreed


https://www.mercurymarine.com/us/en/...eller-selector

[moselpirat]

thx, I will try that out.

[shrew]

The key to sizing a prop is determining your max RPM at Wide Open Throttle (WOT). take the boat out with light weight/nominal loading (don't do this with 5 guests on board).

Get the boat up on plane, then get the drive trimmed out as far as it will go without cavitating. get the tabs trimmed minimally. Get the boat up to wide open throttle.

At WOT the max RPM range is 4400-4800. If you are in that range, you are propped correctly.

Every 1 inch of pitch will adjust the rpm +/- 100 rpm. So going up 2 inches in pitch will reduce max RPM by 200. Dropping 2" of pitch will raise teh max rpm by 200.

If you're at 4400 leave it alone.

If you ALWAYS run with heavy loads, then you should decrease pitch.

Increased pitch will lengthen time to plane, but increase max speed.

Decreasing pitch will shorten time to plane, but decrease max speed.

The prop is based on that math. IT doesn't matter if you 'think' it should be faster. If you're within 4400--4800 rpm at WOT, then that is the prop and the speed. If it's too slow, it's time to look at faster boats.

Then again, this is a cruising boat, not a speed boat.

[yahoo82]

All great suggestions above. There are also some prop “features” other than pitch which can impact performance, but you should have a target pitch first based on the WOT test.

Material - stainless will perform better (stiffer and slimmer blades) but aluminum is safer on impact.

Blades - generally 3 blade will give better WOT speed and efficiency while 4-blade give better hole shot.

Hook - like adding an 4th blade, it adds more “grip” to prevent prop slip. If your motor feels like it’s really sluggish getting on plane, then less grip can be better to let the prop slip a little and spin up into the engines torque range. If the engine is able to spin up to 3,000 rpm plus but it feels like it’s slipping and not “pushing” then more cup and/or hook can reduce the slip and transfer more of the available power to the water.

Cup and Blade rake angle - impacts how much it can “lift” the back of the boat while getting in plane. A rear-heavy boat that tends to plow can benefit from these changes (plus 4-blade and hook per above).

https://continuouswave.com/whaler/reference/prop3.html

https://www.mercurymarine.com/us/en/...ptimal-boating


These guys are awesome and can also help: https://propgods.com/