Hi I love my Hunter 30, but it really sucks going into the wind, especially when it's up around 20 knots. My 13 hp Yanmar just has not got enough power. A fellow sailor told me I should look into a different prop. I was wondering if anyone out there has solved this problem. I know all of the Cherubini Hunter 30's were under powered. My engine has been completely rebuilt and runs great. If adding a different prop would make the difference I would like to know. Thanks.
No power into the wind
- Thread starter RussNorman
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Russ: One of our fellow sailors just replaced his stock prop with a Campbell Sailor Prop. He claims he has picked up at least a kt in speed. We are going to do a real test this weekend with a 30 mile cruise out on his new prop.
.....to be continued!
.....to be continued!
If you are working with the original two-blade or something like it then yes, a new prop can make a huge improvement. My H37C at 18000# was underpowered with the 20hp 2QM. I changed to a Flex-O-Fold two-blade and got more power, more speed, and better backing. Now with 30hp and a three blade Flex-O-Fold it is amazing. Just the right fixed 3-blade will help a lot.
Kinda complex question.. First, you have to know the rpm where the engine makes the most horsepower.. usually the “rated” constant output RPM.. Next get a reliable and accurate tachometer (the stock ones are notoriously inaccurate) .. low cost contact or optical tachometers are OK.. The contact one is fine if you have easy access to the center of the front pulley and enough space to put the tach there.. if not, an optical will be necessary.. read the crankshaft RPM on that main front pulley ..
http://www.harborfreight.com/digital-contact-tachometer-66400.html
Next, using the tachometer make sure that the engine can get to the rated rpm with no load.. requires two people .. ya don’t have to do that for long to get a reading..
Correct that if it can’t.. If it can, then go out on calm water with very little wind and run at maximum throttle for a bit then take a tachometer reading to find if the engine is at or very close to its rated RPM.. If it is significantly lower that rated, then you’ll be able to change prop pitch to a lower number and get some more UMPH into wind/waves.. That process is the only way to actually tell if your prop pitch is correct.. A three blade may marginally help as well if your pitch is found to be correct.. Alternately, a good prop shopwith some sailboat experience can be consulted for advice ..
As others have noted, do this with a clean prop and bottom and clean fuel filters ..
http://www.harborfreight.com/digital-contact-tachometer-66400.html
Next, using the tachometer make sure that the engine can get to the rated rpm with no load.. requires two people .. ya don’t have to do that for long to get a reading..
Correct that if it can’t.. If it can, then go out on calm water with very little wind and run at maximum throttle for a bit then take a tachometer reading to find if the engine is at or very close to its rated RPM.. If it is significantly lower that rated, then you’ll be able to change prop pitch to a lower number and get some more UMPH into wind/waves.. That process is the only way to actually tell if your prop pitch is correct.. A three blade may marginally help as well if your pitch is found to be correct.. Alternately, a good prop shopwith some sailboat experience can be consulted for advice ..
As others have noted, do this with a clean prop and bottom and clean fuel filters ..
One of the problems on these early Hunters is that they did NOT have a tach. This makes the problem even harder to determine. I must assume that is also the case with Russ's boat.
Alternative to OEM Tach
http://cgi.ebay.com/Digital-Photo-L...emQQptZLH_DefaultDomain_0?hash=item3a5583ffa2
Here's an alternative to an OEM Yanmar tach if one is not on the boat, or if there is doubt about its accuracy. At only $19 inclusive of shipping, the laser might be worth it? To get the rpm reading, one sticks some reflective tape on the item to be measured (crankshaft pully in this case), then aims the laser at the area while the engine is running. Guess that the engine must be be oriented so the laser can be aimed safely at the crankshaft pully. taking care not to get fingers, clothing or long hair caught in the alternator/pump belt!
http://cgi.ebay.com/Digital-Photo-L...emQQptZLH_DefaultDomain_0?hash=item3a5583ffa2
Good Results with Campbell Sailor
http://forums.sbo.sailboatowners.com/showthread.php?t=112587&highlight=Prop+Review+Campbell+Sailor
Re Steve Dion's reference to a friend's Campbell Sailor Prop. Same experience for me. A couple of months ago I replaced my two bladed Michigan Wheel prop with a three blade Campbell Sailor prop. The 20HP 2QM20 Yanmar isn't a lot of engine (although its really big and heavy) for the 14,000 lb displacement of my boat but even with the 2-blade going forward again chop and current wasn't a problem. However the boat definitely has more drive under power with the Campbell prop. The boat goes faster at less RPM and less vibration. The prop is probably also be one of the reasons my boat is going faster under sail than it did before. A further benefit is less severe prop walk in reverse than with the two blade. MaineSail a ways back posted a review of the Campbell Sailor prop. Here's a link to the thread:
http://forums.sbo.sailboatowners.com/showthread.php?t=112587&highlight=Prop+Review+Campbell+Sailor
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Rardi:
We have one of these and will be using it to test his RPM, but this is not too practical when trying to power thru the flood/ebb.
We have one of these and will be using it to test his RPM, but this is not too practical when trying to power thru the flood/ebb.
More of the same
I was following this thread and saw mention of the three blade props, beyond potentially improving speed, also helping with prop walk. I dread backing the boat into my slip if it is anything other than dead calm and slack tide. I can compensate for the prop walk in those conditions but the least bit of external force and a five minute docking with one pass can take a half dozen tries.
The easiest way to aviod being laughed at whe this happens is to get the more experienced person behind the wheel. After they fail a few times I feel better and the teasing stops but I am looking for a better solution. When I single hand it that doesn't work well.
Besides this year they have put an absolutely beautiful Columbia in the next slip and I live in fear of hitting it.
Will a three blade really make a difference in reverse?
Oddly even with more than 20 knots of headwind my YSB 12 seems to hold its own forward, but give me no knots and a little bit of wind and I won't get on the dock even when I get there.
I was following this thread and saw mention of the three blade props, beyond potentially improving speed, also helping with prop walk. I dread backing the boat into my slip if it is anything other than dead calm and slack tide. I can compensate for the prop walk in those conditions but the least bit of external force and a five minute docking with one pass can take a half dozen tries.
The easiest way to aviod being laughed at whe this happens is to get the more experienced person behind the wheel. After they fail a few times I feel better and the teasing stops but I am looking for a better solution. When I single hand it that doesn't work well.
Besides this year they have put an absolutely beautiful Columbia in the next slip and I live in fear of hitting it.
Will a three blade really make a difference in reverse?
Oddly even with more than 20 knots of headwind my YSB 12 seems to hold its own forward, but give me no knots and a little bit of wind and I won't get on the dock even when I get there.
Re: More of the same
MLampner:
Going back over the last couple of years, I also posted the same question as you about 3-blade props vs 2-blade and reverse prop walk. Many different opinions were given. I also talked to prop shops ... one was quite certain no improvement would be noticed. Other's said maybe. Each boat model is different.
That said, the Campbell Sailor prop definitely has been an improvement for reverse prop walk on my boat. Note the Campbell prop has a very different design that the usual dumbo ear type of three bladed prop. Reverse prop walk is still there, but not nearly as much. And some reverse prop walk can be a good thing.
When leaving my slip, I still find it easier to first push my boat backwards from the dock by hand to generate some intial steerage way, then I get on the boat to complete the leaving process. But also, if the wind is still, I am now able to back out of my slip more-or-less straight without the port stern ending up firmly on the left finger and the bow scraping along the right finger as I always did before. The Campbell prop has fine bite going forward, but compared to my previous 2-blade, for reverse I have noticed that I now need to budget more time/distance and use more rpms's to slow down. The performance results for Campbell prop show it has less resistance under sail than most props, which probably also accounts for less braking power in reverse.
Upshot: Trying a different prop is an experiment. And one that unfortunately needs some money to set up.
If you do try something different, please post your result. Other's might have interest to know.
MLampner:
Going back over the last couple of years, I also posted the same question as you about 3-blade props vs 2-blade and reverse prop walk. Many different opinions were given. I also talked to prop shops ... one was quite certain no improvement would be noticed. Other's said maybe. Each boat model is different.
That said, the Campbell Sailor prop definitely has been an improvement for reverse prop walk on my boat. Note the Campbell prop has a very different design that the usual dumbo ear type of three bladed prop. Reverse prop walk is still there, but not nearly as much. And some reverse prop walk can be a good thing.
When leaving my slip, I still find it easier to first push my boat backwards from the dock by hand to generate some intial steerage way, then I get on the boat to complete the leaving process. But also, if the wind is still, I am now able to back out of my slip more-or-less straight without the port stern ending up firmly on the left finger and the bow scraping along the right finger as I always did before. The Campbell prop has fine bite going forward, but compared to my previous 2-blade, for reverse I have noticed that I now need to budget more time/distance and use more rpms's to slow down. The performance results for Campbell prop show it has less resistance under sail than most props, which probably also accounts for less braking power in reverse.
Upshot: Trying a different prop is an experiment. And one that unfortunately needs some money to set up.
If you do try something different, please post your result. Other's might have interest to know.
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