Prop recommendation for 2101 striper

[monster1]

Hey guys. I have a 2101 striper walk around cuddy with hard top. It's has 4.3gxi volvo penta engine and 1.66 geared out drive. I'm currently running a 14 3/4 x 17 Ballistic ss prop. It takes 6.5 seconds to plane and the boat goes 36 knots at 4800 rpm which is max WOT for that engine. I'm not looking for speed. I need better hole shot and better cruising when the boat is loaded. I'm assuming I should go with a 4 blade with 2" less pitch but wanted to see what you guys recommend.

Thanks

 

[steelespike]

Seems like a reasonable approach.Usually suggested to reduce 1".

 

[Sea Rider]

What happens if no 1 pitch reduction is available in 4 blade props, larger props usually come in +, - 2 pitch sizes ? If OP is already at max wot revs, going for one less prop pitch should achieve same theoretical 4800 wot revs, right ? if achieving same wot revs with both props, will a 4 blade still achieve better hole shot ? If wanting better hole shot while more loaded than usual a 2 pitch reduction will probably match much better. Bear in mind that when lightly loaded max wot rpm will rise accordingly, so watch tach not to overrev. Being all tech assumptions, in reality must try props while combo is running while trial & error.

Happy Boating

 

[monster1]

We all know dropping pitch will increase rpm but from what I've read, the extra blade increases drag which lowers rpm so a 4 blade with 2" drop should stay the same at WOT. just wondering if 4 blades is enough. I heard the merc high five works wonders.

 

[Sea Rider]

If say, you are running a 3 blade prop that produces 5500 wot revs and you go for a 4 blade prop with one less pitch should achieve same 5500 wot revs, if you go 2 less in pitch wot revs should go higher than 5500. Go for a 4 blade prop with 2 less in pitch as a starter and check wot performance. Anyway whichever prop you go after will need to test it while combo rides lightly loaded under trial & error.

Happy Boating

 

[monster1]

I've read a lot of posts online and issues people have been having. Maybe I'm not so bad off after all. My prop slippage is only 10% at WOT. And 6.5 seconds to plane is a lot better off than some people who claim 30 seconds to plane. My boat is a heavy deep vee hull. It's going to take more to pull it out of the water. I don't need a speedboat. In fact fuel economy is more important to me than plane times or speed. Next time I'm out I'll get more data throughout the speed range to see how my numbers are. I don't want to just blindly start buying props. Maybe I'm fine where I'm at.

 

[Sea Rider]

To dial spot on props for particular boating purposes could result in costly water testing. One story is boating very lightly loaded on a heavy combo, other fully loaded. With same prop illustrating both examples, as the weight increases wot rpm will decrease from 4800 accordingly.

Test that combo more or fully loaded as intended, post max wot rpm achieved, expect to be towards the lugging zone. Can go from there dialing other prop to pull wot revs again towards 4800 rpm as when lightly loaded.

Once you dial the perfect prop that delivers max wot rpm while heavyly loaded, will achieve good hole shot, nice speed & fuel consumption throughout the whole throttle range.

Happy Boating

 

[Maclin]

monster1,

I think your numbers are very good. Had to convert 36 knots to 41-42mph in the prop calc-er I use, then you are right at 10% slip and are reaching top RPMS in the MFG suggested power band.

What equipment and gear do you have (Extra batteries, charger, bait and live wells, coolers, galley, etc) and how is it distributed?

Your numbers suggest that maybe a 16p 4 blade would be a good choice to focus on hole shot and lower speed on plane cruising. But like I said, you are getting the right numbers now with that low of slip% and being at top of RPM band.

 

[Sea Rider]

OP will need to state if was lightly loaded or solo boating when achieved 4800 max wot rpm, top max wot rpm would be impossible to match while heavyly loaded, family oriented. Is the actual Ballistic prop a 3 or 4 blade prop ?

Happy Boating

 

[monster1]

Thanks for your replies guys. I'm taking the kids out tubing tomorrow so I'll post better numbers.

 

[dingbat]

226 Grady walkaround. Running a 14 1/2 x 17 Renagade Offshore with great success. Stays hooked up in the slop. Can't complain about how fast it gets a #5400 boat out of the hole