I had Jack's Place hauled today to install a new Max-Prop three blade feathering propeller. After going back into the water, I took the boat for a mini spin and immediately noticed there was no vibration...at all! Everything was very smooth. With my old fixed two blade, I had noticeable prop walk. Now, there is literally nothing that brings the boat to port. I was able to totally stop the boat within half a boat length from 4.5 knots and then begin to back down. We're getting the crew together for some practice this weekend and I will report on how well the boat behaved herself with this new gizmo. For the curious minded, I just did a substantial update on our web site which includes lots of pictures of today's events. Smooth sailing, John Richard s/v Jack's Place
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Attaboy
Good estimate on the right pitch of the prop, since sometimes it take two or three dunks to get it just so. I've had the Max-Prop two-blade for six years and love it. One unintended benefit was a much more hefty thrust in reverse.
Good estimate on the right pitch of the prop, since sometimes it take two or three dunks to get it just so. I've had the Max-Prop two-blade for six years and love it. One unintended benefit was a much more hefty thrust in reverse.
Yep,
It's kinda like popping the parachute on a race car, or leaving the pier and forgetting to untie a line.
P.S. John, just came back from your web site. You are going to love that prop. Interesting about the crocus cloth work to remove the .001" interference. I've done a couple of these installs including a 3 blade like yours. They both had the high spot. I'll be sure and talk to PYI about the place to remove material. Thanks for the info.
It's kinda like popping the parachute on a race car, or leaving the pier and forgetting to untie a line.
P.S. John, just came back from your web site. You are going to love that prop. Interesting about the crocus cloth work to remove the .001" interference. I've done a couple of these installs including a 3 blade like yours. They both had the high spot. I'll be sure and talk to PYI about the place to remove material. Thanks for the info.
Lower Revs
John, It would appear that you are now a little over propped. If you have to run flat out for about 30 minutes in an emergency you may well discover she overheats. I went this route on my 376, got the benefits but now have the occasional overheat. It happened when we were trying to outrun the fleet in the America's cup 150 year celebration. Quite scary as my pal who was helming just cut the engine when the alarm sounded and we were dead ahead of all the J boats hotly followed by the AC fleet. I then had a bright idea. We turned on all the hot water faucets and the calorifier re-filled with cold water. This acted on the cooling water. Re-starting the engine circulated the overly hot water through the calorifier and we were then able to motor across the fleet to (comparative) safety. For interest you may also get some cavitation when butting into a head sea. I intend to reduce my pitch to less than 22 degrees next haul out.
John, It would appear that you are now a little over propped. If you have to run flat out for about 30 minutes in an emergency you may well discover she overheats. I went this route on my 376, got the benefits but now have the occasional overheat. It happened when we were trying to outrun the fleet in the America's cup 150 year celebration. Quite scary as my pal who was helming just cut the engine when the alarm sounded and we were dead ahead of all the J boats hotly followed by the AC fleet. I then had a bright idea. We turned on all the hot water faucets and the calorifier re-filled with cold water. This acted on the cooling water. Re-starting the engine circulated the overly hot water through the calorifier and we were then able to motor across the fleet to (comparative) safety. For interest you may also get some cavitation when butting into a head sea. I intend to reduce my pitch to less than 22 degrees next haul out.
Speaking of Max Prop, got a question....
Forgive me for hijacking this thread, but since we're on the topic, I have a H31 with 2 blade max prop which was installed by the previous owner and the 2GMF13 Yanmar is belching some smoke at high RPM's. The PO tried everything fuel related to stop the smoke and never did. One possibility is that the prop pitch is maladjusted. Question.....I had to quickly drop the boat back in the water after a bottom job due to Hurricane Ivan bearing down on us, and never got to check prop pitch. Is there anyway to go down with tanks (or without tanks) and remove the prop to lube and check the pitch? Advice appreciated.
Forgive me for hijacking this thread, but since we're on the topic, I have a H31 with 2 blade max prop which was installed by the previous owner and the 2GMF13 Yanmar is belching some smoke at high RPM's. The PO tried everything fuel related to stop the smoke and never did. One possibility is that the prop pitch is maladjusted. Question.....I had to quickly drop the boat back in the water after a bottom job due to Hurricane Ivan bearing down on us, and never got to check prop pitch. Is there anyway to go down with tanks (or without tanks) and remove the prop to lube and check the pitch? Advice appreciated.
Update and an answer to Gary
Gary: After watching the installation, I strongly feel that the best way to adjust the pitch on the prop is to do so out of water. To do this adjustment, there are several operations that need to be completed to access the gears that dictate prop pitch. Included here are seveal parts that must be removed/replaced. Doing this under water might pose a problem. But, and this is a major "but", if the diver is FULLY acquainted with this type of prop, he might be dexterious enough to pull it off. If it was me, I would definitely opt for a haul out. This way, none of the parts will be dropped. Everything on the Max Prop is metric; it's made in Italy. So, if you lose a part, you might find it difficult to find a replacement. There are two Max Prop models. The one I bought is the "Classic." It is not able to be adjusted externally. The "VP" is the only one that offers the ability to change while the boat is in the water. It retails for about $400 more than the "Classic." The Classic is best modified while out of the water. I have some new information. After doing a run at full throttle and reaching only 3400 rpm and knowing the engine is rated at 3650, I called PYI. The rep told me, after hearing these numbers, that I should change back to 20 degrees. He said that the increased pitch overload would cause the motor to overheat while running at the same rpm's to produce the expected SOG. In the long run, I would see that the engine's life time would be shorter. He said that under normal use the engin might go 10,000 hours and that under the increased pitch conditions I might get only 8,000. I plan to run at 2700/2800 (compared to a normal 3000) until I haul the boat in October for new bottom paint. At that time, I'll have the prop changed back to 20 degrees. John Richard s/v Jack's Place
Gary: After watching the installation, I strongly feel that the best way to adjust the pitch on the prop is to do so out of water. To do this adjustment, there are several operations that need to be completed to access the gears that dictate prop pitch. Included here are seveal parts that must be removed/replaced. Doing this under water might pose a problem. But, and this is a major "but", if the diver is FULLY acquainted with this type of prop, he might be dexterious enough to pull it off. If it was me, I would definitely opt for a haul out. This way, none of the parts will be dropped. Everything on the Max Prop is metric; it's made in Italy. So, if you lose a part, you might find it difficult to find a replacement. There are two Max Prop models. The one I bought is the "Classic." It is not able to be adjusted externally. The "VP" is the only one that offers the ability to change while the boat is in the water. It retails for about $400 more than the "Classic." The Classic is best modified while out of the water. I have some new information. After doing a run at full throttle and reaching only 3400 rpm and knowing the engine is rated at 3650, I called PYI. The rep told me, after hearing these numbers, that I should change back to 20 degrees. He said that the increased pitch overload would cause the motor to overheat while running at the same rpm's to produce the expected SOG. In the long run, I would see that the engine's life time would be shorter. He said that under normal use the engin might go 10,000 hours and that under the increased pitch conditions I might get only 8,000. I plan to run at 2700/2800 (compared to a normal 3000) until I haul the boat in October for new bottom paint. At that time, I'll have the prop changed back to 20 degrees. John Richard s/v Jack's Place
Gary, there are several different designs
of Max Props. Some are adjustable easily in the water and some are not. My guess is that it is not. Talk to PYI or look at your book to figure it out. What speed do you get at what rpm? Did you check your exhaust elbow?
of Max Props. Some are adjustable easily in the water and some are not. My guess is that it is not. Talk to PYI or look at your book to figure it out. What speed do you get at what rpm? Did you check your exhaust elbow?
Gary, This prop is available in a externally
adjustable pitch model. I don't know how to tell if you have it, but if you do, the pitch can be changed with just a quick free-dive. Seems that there is an adjusting collar at the rear of the hub. Not too many folks have them. Something about a 50% price penalty. And then once you get it right, you don't need it again. P.S. Patrick! you beat me to it again. Drat!
adjustable pitch model. I don't know how to tell if you have it, but if you do, the pitch can be changed with just a quick free-dive. Seems that there is an adjusting collar at the rear of the hub. Not too many folks have them. Something about a 50% price penalty. And then once you get it right, you don't need it again. P.S. Patrick! you beat me to it again. Drat!
The prop might not be the problem....
But I just have had a gut feeling it could be. The mixing elbow has been replaced and the PO said he did everything except replace the fuel injector pump. I don't know what level of competence his mechanic was, but as much as I like doing things myself, I might have to bite the bullet and hire a diesel mechanic to make sure I get it right. Other tips.....I checked the oil level and it is very high, only about 3/4 inch from the top of the dipstick, but viscosity didn't look to be diluted with fuel. Thnaks
But I just have had a gut feeling it could be. The mixing elbow has been replaced and the PO said he did everything except replace the fuel injector pump. I don't know what level of competence his mechanic was, but as much as I like doing things myself, I might have to bite the bullet and hire a diesel mechanic to make sure I get it right. Other tips.....I checked the oil level and it is very high, only about 3/4 inch from the top of the dipstick, but viscosity didn't look to be diluted with fuel. Thnaks
Oil level might be the problem
It can become a really big problem if it starts to become fuel. The engine can experience uncontrolled overspeed if it becomes hot enough. Better drain it and figure out the reason it is so full before you start changing the prop or anything else. Any mechanic who did not catch this is clearly not competent in my opinion. My suggestion is to fix the oil level and see what the boat speed versus engine speed does and if and when it starts to smoke. I would still take a look at the exhaust system (elbow) if there is a problem. Did I miss anything, Fred?
It can become a really big problem if it starts to become fuel. The engine can experience uncontrolled overspeed if it becomes hot enough. Better drain it and figure out the reason it is so full before you start changing the prop or anything else. Any mechanic who did not catch this is clearly not competent in my opinion. My suggestion is to fix the oil level and see what the boat speed versus engine speed does and if and when it starts to smoke. I would still take a look at the exhaust system (elbow) if there is a problem. Did I miss anything, Fred?
Just the primary fuel pump Patrick.
If the membranes toast, diesel goes into the crankcase. Good job Patrick.
If the membranes toast, diesel goes into the crankcase. Good job Patrick.
Gary,
An overfull crankcase will drasticly reduce available power as the crank drag is increased by going thru the extra oil. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
An overfull crankcase will drasticly reduce available power as the crank drag is increased by going thru the extra oil. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
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