Three blade suggestions

[Selleck95]

I have a 1989 sea ray 210 that I stripped to the hull and rebuilt. Along with the rebuild I bought a new Rapido short block and installed vortec heads and an affordable injections complete tbi set-up with large distributer. The boat runs great other than an issue with the shift interrupt.

The alpha one had a 1.51 ratio and came with a beat up 21 pitch 3 blade. I purchased a 21 pitch four blade turning point prop. I was only able to spin 3500 rpms at 42 mph on the GPS. I then dropped down to a 19 pitch turning point four blade and was able to reach 4100 rpm at the same 42 mph. This was on relatively choppy water. I was not able to fully trim. I don't think there was alot more speed or rpm to be had though.

I am now thinking of going back to a three Blade and looking for suggestions. I feel I am down on performance and I am thinking the style of prop I am using does not fit the boat.

 

[jimmbo]

I have a 1989 sea ray 210 that I stripped to the hull and rebuilt. Along with the rebuild I bought a new Rapido short block and installed vortec heads and an affordable injections complete tbi set-up with large distributer.

That doesn't really tell anyone anything about what the engine is.
a 1:1.51 gear ratio is usually used with 5.7 engines. I haven't seen any USCG approved Aftermarket FI systems,

If the engine was a 5.7 and had a 1:51 gear ratio, a 3 blade 21 inch prop would be too much on a 21 ft boat, perhaps ok on an 18 ft, but not on a 21ft I would think a 3 blade 19, maybe a 3 blade 17 would be correct for your combo.

 

[Selleck95]

I apologise for not including the engine. Not sure how I missed that. It is a 5.7 880 block. I assumed the 21 pitch three blade was original to the boat. I never considered that may not have been the case. The injection system is a marine converted gm tbi setup from affordable fuel injection.

My real concern here is that the boat is performing at it's best and there is not an underlying issue causing the lack of RPM. Does 42 MPH seem slow for this boat to anyone?

 

[Starcraft5834]

my 2 c. 1989 motor is not new. engine might be tired... 4200 rpm is about 400-600 short of where you should be running it... then again if it's tired... 4200 is not a bad place to be.... in theory.. you could drop down pitch by 2-3, (as Jimbo said) to hit 4800....

frankly, I'd leave it alone... if it's running happy at 4200 and getting on plane out of the hole for you.. leave it.. if it plows and doesnt jump out of the hole, consider a 4 blade..

 

[Selleck95]

The engine is not tired. It is a rebuilt engine from rapido marine. Roller lifters and vortec heads. I am happy with the hole shot but feel I am lacking top end. It cruiser fine but I do think the prop is more than what I should be running. I want to ensure it is proped correctly.

 

[dingbat]

I then dropped down to a 19 pitch turning point four blade and was able to reach 4100 rpm at the same 42 mph.

This is 16% slip.

No wonder you think it's slow..... 5% slip would put you close to 48 mph

What you'll find is that 4 blade props have far too much slip at the top end. I liked my 4 blade for hole shoot but wasn't going to concede 3 mph for a negotiable, if any, increase in low end performance. Got rid of the 4-blade and went to a 3-blade Mercury Enertia prop.

The Enertia isn't cheap, but it kept my hole shot in place while picking up almost 3 mph at WOT and a 10% increase is fuel mileage to boot.

 

[Faztbullet]

Something wrong with motor as it should turn a 21pitch or boat is heaaaavy

 

[QBhoy]

Something wrong with motor as it should turn a 21pitch or boat is heaaaavy

No way it will turn a 21” easily faztbullet. Not with that ratio. It would need to have a serious hull...stepped and pad hull and be much lighter would help.
It might even struggle with a 19” to see near the top end of the rpm range. If it can run a 19” that would be great. But I suspect it might struggle in other areas down the rpm range...if it can. But for me, a 21” is out the question. Just my opinion.

 

[Faztbullet]

Check this out....should spin a 19-21 easy. I just serviced a 17-1/2 Ray with 3.0 that spins a 24P at 4200 and got its twin in for boot that has a 21P
https://www.youtube.com/watch?v=fzrTrKCD3Ms

 

[dingbat]

Check this out....should spin a 19-21 easy. I just serviced a 17-1/2 Ray with 3.0 that spins a 24P at 4200 and got its twin in for boot that has a 21P
https://www.youtube.com/watch?v=fzrTrKCD3Ms

You comparing a 17-1/2’, #2000 boat to a 21’, #3000 boat with 6” more beam.

People and gear would push you over 2 tons.

 

[jimmbo]

I have an 18 1/2 ft with a 5.7 and 1:1.51 ratio, it would spin a 21 AL at 4700, so on a 21 ft it would be too much prop

 

[Selleck95]

Thank you for all the responses. I am still dialing everything in. I have a 17 pitch three blade I may try. I order a 19 pitch turning point three blade and I am hoping to try that this weekend. I will report back with my findings.

 

[Scott06]

Thank you for all the responses. I am still dialing everything in. I have a 17 pitch three blade I may try. I order a 19 pitch turning point three blade and I am hoping to try that this weekend. I will report back with my findings.

Did you check the tach against a shop tach to verify your dash tach is accurate?

 

[QBhoy]

Check this out....should spin a 19-21 easy. I just serviced a 17-1/2 Ray with 3.0 that spins a 24P at 4200 and got its twin in for boot that has a 21P
https://www.youtube.com/watch?v=fzrTrKCD3Ms

That’s a 5.7 gxi in the video. About 300-320hp. Different thing altogether

 

[achris]

Check this out....should spin a 19-21 easy. I just serviced a 17-1/2 Ray with 3.0 that spins a 24P at 4200 and got its twin in for boot that has a 21P

3 litre engines run a 1.94:1 drive ratio. A 5.7 runs a 1.47:1. That's a HUGE difference. I agree with all others here, 21" is way too much for that boat.

Thank you for all the responses. I am still dialing everything in. I have a 17 pitch three blade I may try. I order a 19 pitch turning point three blade and I am hoping to try that this weekend. I will report back with my findings.

Be aware, Turning Point props are known to be inefficient. I ran some tests with TP and Merc props, and on the same boat, the TP prop needed to be AT LEAST 2" shorter to allow the same WOT revs, and ended up being good a few knots SLOWER...

Chris......

 

[jimmbo]

My beef regarding TP props is a Lack of QC, a couple of Years ago I opened several TP boxes, and examined the Props. As I was doing so, a Sesame Street Song started going through my Head. 'One of the these Blades is not like the Others, One of these Blades just doesn't Belong...' One of the Blades would be bent as in More Rake than the other 2.They are mainly a Price Point type of Prop.
Their Blades tend to be thicker than Mercury's AL offerings. I know they were using a Term called 'Squeeze Casting' in their Marketing. I remember some guy at the lake telling me how fantastic his Squeezed Cast Prop was, compared to my Enertia.. I just nodded, smiled and proceeded to display my Boat's Transom for the next several miles

 

[achris]

Squeeze casting just means that once the metal is in the mold, it's put under pressure. Has nothing to do with mold shape or consistency.

 

[Selleck95]

I am coming to the same conclusion about TP. I was able to run the 3 blade 19 pitch this weekend. I hated everything about it. My cruiser speed is closer to 3k now, the boar did not plane nearly as well. Unfortunately I was not able to get a gpa speed our day was cut short. My dad has a 40 ft Silverton express with two 502s pushing through vdrives. It seems he hit a log on the way back in after meeting up with me. It broke the shaft from the transmission and pulled it out of the bottom of the boat while taking the rudder with it. The boat began taking on water from the now empty hole where the shaft was. It was a stressful situation. My 19 pitch prop is now ruined from a nice rock I found while pulling him off of the rocks he drifted into.

Back to prop selection. I think I would like to go back to a four blade. I would like to get away from turning point all together. Speed is not priority efficiency and cruise comfort are my priorities. I would like to stick with AL due to cost. Should I look more into Quicksilver props? I am thinking a 19 pitch four blade that is a brand other than turning point may be the direction to go. I had a 19 pitch four blade Solas on the boat the second time I had it out. I reach 4400 RPM with no trim. The lake was extremely rough.

 

[Selleck95]

Any reviews on the Quicksilver nemesis? I have read good things so far. The price is not bad.

 

[Scott06]

If you want an affordable 4 blade try a Michigan vortex. You should be able to use your current hub kit. I think nemesis is the quicksilver version of the spitfire (quicksilver is the brand they sell outside their dealer network). I have a spitfire that at least on my boat was unimpressive. Lot if slip