New prop and she really moves.

[BrazDaz]

Hey guys,
I wrecked my prop last weekend just pottering around the beach when I realized I was motoring over rocks, (not sand as i thought ) when whack, busted prop.
I went to the new MacGregor dealer here in Perth, who I had been talking to for a while. He had been telling me I had the wrong prop on for a couple of weeks but I didn't really believe him because I thought the one that came with the boat should be the right one, (bought from another dealer a long way a way).
He had one on the shelf and did me a great deal on an after market Prop, different size but I tried it any way and Wow she goes like a cut cat, I never did any speed trials on the old prop but she seems 10-20% faster.
Thanks Klaus at eco Yachts

Daz.

[Hamin' X]

Might want to share the prop make, size and pitch, as well as your outboard.

~Rich

[ksatterlee]

Yes, please share.......name and location of dealer, prop size, engine size.
Thanks!

[second wind too]

I am currently trying to work out the proper prop for my 2006 26M with a 50HP four stroke Yamaha. When I bought the boat it had a 3x14x11 prop and only gets a max of 4600 rpm and about 13.5 knots. I just changed to a 3x13-5/8x13 which came with the boat s a spare and will see if I can get my rpm and speed up with that prop next trip.

Any prop suggestions for my boat and motor? Weight is probably average, nothing exceptionally heavy on the boat (except me maybe ...) Weight of course, can change as much as 400 pounds each time out depending on how many crew. Would love to hear from anyone with same boat and motor. Thanks.

[BrazDaz]

Hey guys
My Prop an motor details are as follows
2007
Motor Evenrude Etech 50
Old prop ome 177202 13- 7/8 x 11 max rpm 5525
New prop make unknown H2 -1413 14 x 13 max rpm 5200
I would say that these numbers are Diameter and pitch, because the new prop tips hit the housing and needed about a paint thickness filed off so it would spin freely (pretty close).
as i said I don't know how much faster but its defiantly noticeable, oh I also polished the hull the day before. And I did notice while driving she slowly steeped up onto the plane as water ballast emptied out. indicating a marked performance increase as the boat got lighter, you all should try this constant mid power setting test about 3500rpm.
i hope this helps others out.
Daz

[Trouts Dream]

The 2 numbers on a prop are normally diameter and pitch. If the pitch number goes up the max engine rpm will be slower, all things being equal.

If the second prop is truly larger diameter and higher pitch then the engine RPM cannot go higher unless there was something seriously deformed in the first prop. I'm glad you have better preformance but you may want to recheck the specs on those 2 props.

[Phil M]

Hey guys
My Prop an motor details are as follows
2007
Motor Evenrude Etech 50
Old prop ome 177202 13- 7/8 x 11 max rpm 5525
New prop make unknown H2 -1413 14 x 13 max rpm 5200.
Daz

I would probably go with a 9" pitch and get the max rpm closer to 6000. The higher the pitch, 11 or 13, the slower the maximum rpm, the harder the engine has to work, but you would get better gas mileage with a higher pitch prop (your engine might not last as long though).

Phil M

[BrazDaz]

Note the RPM has reduced,

[Trouts Dream]

It was late when I read the post..my bad....

I try to always keep the RPM in the manufacturers recommended max range as it reduces the load on the leg.

[Starscream]

Based on some previous threads on this board, I too changed my prop after a bottom strike. I bought an OEM Honda 4 - 11.8 x 9 to replace the unmarked 3-blade that came with the boat. Honda BF50. Original 3-blade maxed at about 6200 RPM so I never ran full throttle. At 6k RPM I had a very consistent 15 mph through the water almost regardless of wind direction.

With the new prop, max RPM is 5,600, and waterspeed hits 16mph regularly and can touch 17mph.

Numbers with no ballast, obviously, and a fairly loaded boat. Feels like an improvement.

[magnetic]

I did quite a lot of investigation into props about 3 years ago on my - basically, I found that a wider prop with narrower pitch gave me far better performance all round -

http://www.macgregorsailors.com/forum/v ... rop#p90767

http://www.macgregorsailors.com/forum/v ... rop#p90765

http://www.macgregorsailors.com/forum/v ... rop#p90232

My current has the fuel-inected Honda BF50 and a 13in pitch prop and at WOT (ballast out, everything up), I topped out at 16.7 knots @6000 rpm - which given that I wasn't noticeably underweighted at the time, I think was pretty ok. Better than I expected, anyhow. By comparison, fully ballasted I was maxing at 13.3kts @ 5,500 rpm WOT.

Nevil who previously owned the boat found that the original 10 inch pitch prop gave him around 10 knots at 5700 rpm, but that was fully laden for a weekend trip

UPDATE

I checked the boat today and the 11 5/8 x 13 prop is still in its box - Nevil must have had a change of heart, and all my figures above are consequently based off a 10 inch pitch, not 13

[DaveB]

Thats great! Max. I got on my 13 year old BF50 was 15.2 Knots and boat was almost empty, best I can do now is 13.8 Knots with heavy weight on boat useing a 4 blade 11.8x12 pitch and rpm's 4600 max.
I have tried many props. and since I cruise at 5.5-6 knots I don't care about top end but lower rpm's for less noise. Fuel consumption is same between props. even tho lower rpms because higher torq. force applied. Before I had to raise rpm's 500-750 to get same speed and more noise.
Maybe the new fuel injection has more torq. I couldn't find any info of spec's compared to the older Carb.
Dave



My current has the fuel-inected Honda BF50 and a 13in pitch prop and at WOT (ballast out, everything up), I topped out at 16.7 knots @6000 rpm - which given that I wasn't noticeably underweighted at the time, I think was pretty ok. Better than I expected, anyhow. By comparison, fully ballasted I was maxing at 13.3kts @ 5,500 rpm WOT.

Nevil who previously owned the boat found that the original 10 inch pitch prop gave him around 10 knots at 5700 rpm, but that was fully laden for a weekend trip[/quote]