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Old 17-10-2012, 14:57   #1
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Sabre 362 motors too slowly... Prop issue?

Trying to gauge how slowly I move under power versus other boats, and what I might be able to do about it.

I've got a 1993 Sabre 362 with a Yanmar 3HJ, 38 hp @3800 rpm. The prop is a 16" 3 blade MAX feathering prop. I've had the boat for just over a year. Sails beautifully, but can't help but notice I just don't move well under power. From what I've read, 2800-2900 rpm represents a good cruising level of throttle. At that level, I do about 4 knots in calm water. Maybe I can pick up a 1/4 to 1/2 knot if I nudge it just above 3000 rpm.

But I feel like I should be able to hit 5 or 6 knots at cruising speed. Other sailboats always seem to pass me by.

Anyone experience something similar? Thoughts on how to address the problem? Is the lack of power just something I need to learn to accept with a feathering prop?

Thanks for your suggestions
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Old 17-10-2012, 15:03   #2
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I would give your displacement, engine specs and gearing to a prop shop and have them calculate the proper dia. and pitch. 16" maybe too small. There are prop calculators on line you can play with that also give you an idea of where you should be.
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Old 17-10-2012, 15:24   #3
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Re: Sabre 362 motors too slowly... Prop issue?

I had a look at the installation instructions for your prop and they seem to be very keen on getting the pitch right.

You could also check with the manufacturer that you have the right diameter prop. for your boat/engine/gearbox ratio, and what they recommend as an initial setting.
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Old 17-10-2012, 15:34   #4
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Re: Sabre 362 motors too slowly... Prop issue?

A 16 inch prop should be quite adequate. My CS36 (similar displacement to your Sabre) has a 16 inch 3 blade fixed prop, 12 inch pitch, and will do well over 7 knots at 3000 revs with a 3GM30F. I usually motor at 2400rpm and she`ll do 6 and a half knots at that.
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Old 17-10-2012, 15:58   #5
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Re: Sabre 362 motors too slowly... Prop issue?

Tash,

Highly likely that your Maxprop is simply overpitched. As soon as you have it repitched you'll be back to cruising at 7 knts. You should be able to get your max engine RPM (or within a couple hundred RPM, anyway) at full throttle in flat water.

You can call a prop shop or PYI or Maxprop, and they can recommend the pitch angle for your boat. You can repitch it yourself or have your yard do it.
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Old 17-10-2012, 16:11   #6
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Re: Sabre 362 motors too slowly... Prop issue?

If your prop is pitched correctly, you should be able to just get to 3700-3800 rpm at wide open throttle, with perhaps a bit of black smoke.

If it is underpitched, it would explain your symptoms.

If it is overpitched or you have engine problems, you will not be able to achieve anywhere near 3800 rpm at WOT, and you will probably see lots of black smoke if you try.

Repitching a MaxProp is easy if you are out of the water, and some can be adjusted without taking them apart. Contact PYI, give them your motor, transmission ratio, and boat type, and they will give you a recommended pitch setting.
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Old 17-10-2012, 17:18   #7
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Re: Sabre 362 motors too slowly... Prop issue?

This can be many things:
- bottom fouled,
- prop fouled / prop not opening properly,
- wrong pitch,
- wrong dia,
- wrong transmission,
- etc.

Take one at a time and eliminate the easy ones first. Prop choice can make dramatic difference in speeds achieved.

Motoring, when you open the throttle, does the engine achieve full rpm? No black smoke? No vibration?

Send your prop type/size to the manufacturer and ask if this prop is good match for your boat.

b.
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Old 17-10-2012, 17:22   #8
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Re: Sabre 362 motors too slowly... Prop issue?

Quote:
Originally Posted by Tash362 View Post
Trying to gauge how slowly I move under power versus other boats, and what I might be able to do about it.

I've got a 1993 Sabre 362 with a Yanmar 3HJ, 38 hp @3800 rpm. The prop is a 16" 3 blade MAX feathering prop. I've had the boat for just over a year. Sails beautifully, but can't help but notice I just don't move well under power. From what I've read, 2800-2900 rpm represents a good cruising level of throttle. At that level, I do about 4 knots in calm water. Maybe I can pick up a 1/4 to 1/2 knot if I nudge it just above 3000 rpm.

But I feel like I should be able to hit 5 or 6 knots at cruising speed. Other sailboats always seem to pass me by.

Anyone experience something similar? Thoughts on how to address the problem? Is the lack of power just something I need to learn to accept with a feathering prop?

Thanks for your suggestions
When was the bottom, including the prop, last cleaned? A dirty prop can have a horrendous effect on motoring performance.
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Old 17-10-2012, 17:32   #9
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Re: Sabre 362 motors too slowly... Prop issue?

Your boat should be much faster than it is. Something is definitely wrong.

I have a 3jh3e and at 2800 r.p.m. I get 6.7 knots. At max power I turn 3900 r.p.m. and get 7.4 knots. I swing an 18 inch prop. My displacement is is similar to yours and my water line length is 2 feet less. I have a "dirty" full keel and a hard chine.

Steve
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Old 17-10-2012, 18:16   #10
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Thanks for all your ideas. Hopefully pitch or something that can be fixed on the prop. Look forward to resolving for next season.
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Old 17-10-2012, 18:33   #11
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Re: Sabre 362 motors too slowly... Prop issue?

If the bottom is clean, you need the prop pitch increased. A diver can do it on a Max Prop.
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Old 17-10-2012, 18:38   #12
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Re: Sabre 362 motors too slowly... Prop issue?

Quote:
Originally Posted by Tash362 View Post
Trying to gauge how slowly I move under power versus other boats, and what I might be able to do about it.

I've got a 1993 Sabre 362 with a Yanmar 3HJ, 38 hp @3800 rpm. The prop is a 16" 3 blade MAX feathering prop. I've had the boat for just over a year. Sails beautifully, but can't help but notice I just don't move well under power. From what I've read, 2800-2900 rpm represents a good cruising level of throttle. At that level, I do about 4 knots in calm water. Maybe I can pick up a 1/4 to 1/2 knot if I nudge it just above 3000 rpm.

But I feel like I should be able to hit 5 or 6 knots at cruising speed. Other sailboats always seem to pass me by.

Anyone experience something similar? Thoughts on how to address the problem? Is the lack of power just something I need to learn to accept with a feathering prop?

Thanks for your suggestions
I downloaded the guide for a maxprop that was given to me. I swagged the initial setting and got it close. Next haulout I tweaked it and got it right.

It can be done in the water but I wouldn't. There are too many bits that can be dropped and aligning the internal gearing is a bit trickly - like 3-handed tricky.

You have plenty of HP and plenty of prop. I would go up an initial 2-3 degrees for next season and see how that goes.
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Old 19-10-2012, 21:53   #13
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Re: Sabre 362 motors too slowly... Prop issue?

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Originally Posted by Ex-Calif View Post
IIt can be done in the water but I wouldn't. There are too many bits that can be dropped and aligning the internal gearing is a bit trickly - like 3-handed tricky.
There is almost never a reason to haul a boat for any prop work and a competent diver can repitch any Max Prop with no problem. PYI has a list of qualified divers around the country that can do this while the boat is in the water. Give them a call and ask.
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Old 19-10-2012, 23:37   #14
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Re: Sabre 362 motors too slowly... Prop issue?

I'd check your bottom first thing. Are you dragging anything? Had a Hunter in our marina complaining about slow motor speed and discovered they had "hooked" a crabpot on their rudder. Been sailing like that most of the summer....go figure????? Love the Chesapeake Bay!!
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Old 20-10-2012, 00:04   #15
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Quote:
Originally Posted by Tash362
Thanks for all your ideas. Hopefully pitch or something that can be fixed on the prop. Look forward to resolving for next season.
We have the same engine and the 2 blade 16" Max-Prop on our J/120 and... After the installation we had the same problem. 4 knots. Now we motor at 7 knots at 2400 rpms. The problem was completely my error. When I installed the prop I was targeting 12" of pitch. I pulled out the Max-Prop instructions and set the pitch to 12 DEGREES. Oops. It turns out that 22 degrees is about 12" of pitch. As clearly shown on the first page of the instructions. Made the correction and now the boat speed is just what it should be.

That said, my transmission ratio is likely different from yours and of course your hull is different so your settings will be different too. Call PYI and get their recommendation.
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