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What I understand from any of your postings is that you are incredibly
insecure, misinformed, and HAVE to have the last word. My point was, Rosalie had performed her own test on drag with prop folded and unfolded and stated her results. You're pointing out that her prop was turning and creating drag really didn't support your fantasy position in this discussion. My fixed prop turns too, when in forward, reverse, or in idle and sailing. In fact, the only time it doesn't turn is when the boat is dockside. Amazing, huh? I've avoided responding to your posts for years, but couldn't when you lamely tried to make Rosalie look bad when all she was doing was participating in a discussion (which she understands better than you do). "JAXAshby" wrote in message ... uhhhhhhhh, mmc? which word didn't you understand? From: "MMC" Date: 8/28/2004 3:34 PM Eastern Daylight Time Message-id: Uh huh, and the point would be? "JAXAshby" wrote in message ... Rosalie, your prop was also turning while you were running the engine. that alone is one hell of a drag. "Paul L" wrote: You will definitely will see a decent speed improvement under sail with a folding prop. Depending on the prop you buy, you should see better power/control in reverse too. They are very reliable now, so I don't think that is a down side. The biggest downside is their cost. I have a Max prop and think it great. Paul www.jcruiser.org "MLapla4120" wrote in message ... I'm going to re-power soon and am also going to get new shaft and prop. It seems that in my boat class (Westsail 32), some people are going to folding props to help speed under sail. I'm for increased speed, but also want reliability. My current bronze propeller is pitted and old. Every time I turn around and look at it, it is full of sea growth. That makes me think I'm getting poor performance. So, I'm for an improvement, but I am unsure of what kind. Any opinions from boaters that have encountered this situation would be appreciated. We have a feathering prop (vs a folding prop) and we do get an increase of about 1/2 knot under sail, and it also backs better under power. I haven't tried to quantify the backing under power - it is just what we feel. Disadvantages are - you lose a bit of power forward because the blades are flat and the prop takes a bit more maintenance than a fixed prop. [We were sailing but had the engine on in neutral so the prop was not feathered - we were running the refrigeration- and when we had finished that, we turned off the engine and feathered the prop, and our speed increased 1/2 knot - same wind and current. Now I know this is not a completely scientific test, but it is significant to us. There are also people in our group who did tests with a fixed prop over a measured course, and then did the same tests with a folding prop over the same course and found a similar result.] grandma Rosalie |
I don't know what a VP/CP prop is. Variable pitch/controlable pitch. I use the terms interchangeably, but as you'll see, others use them slightly differently. When our engine is running the shaft is spinning because we have a Borg-Warner transmission. Our shaft spins whenever the engine is on regardless whether it is neutral or not. The prop feathers when the engine is turned off and the shaft stops spinning. The stopping of the shaft spinning feathers the prop if I understand it correctly. You really wouldn't want the prop feathered if the engine was on - if it feathered when you went through neutral when docking or something it would be very awkward. Interesting, thanks for the info. I would wonder if once you were underway and using your prop, even going from ahead to astern (unless you had a shaft brake) that the shaft would generally continue to rotate on it's own, keeping the prop "unfeathered", though I can see where the manufacturer might want to guarantee it would stay that way (just clarifying in my own mind G). Shen |
On Sat, 28 Aug 2004 12:48:25 -0400, Glenn Ashmore
wrote: 20 miles a day is a 15% improvement on a base 5.6 knot cruising speed and you are correct that folding props make the most difference in light air. Reducing drag has the advantage over adding sail area in that it does not add to heeling moment. BTW, Gori, Martec, Brunton/Varifold and others make 3 blade folders. Volvo even makes a 4 bladed folder. Now, you can continue to rant and make an ass of yourself as usual but that is all I have to say about it. For what it's worth: Buddy of mine with a steel Wallstrom-designed (partner to Brewer) 1979 ketch popped for a three-bladed AutoProp, a feathering design. He had to haul out for many reasons: 1) to confirm the exact geometry of his hull around the shaft; 2) to cut back his rudder at that point for the install; and 3) to get the prop itself on. 1) was because it's essentially a custom casting, and NOT cheap (about $3,500 Cdn.). After three seasons now, he's happy as a clam with his decision and outlay. He says the following: Advantages: Bigger prop, better bite and power curve. He's got a 35 HP Volvo (probably 15-25 HP too small for a 28,000 lb. boat), but according to him, the power he transmits to the prop is greatly increased. His top speed without redlining has gone from 6.5 to 8.2 knots, or approximately hull speed. He says he gains 1/2 knot due to the self-feathering action, a significant gain in typical light Lake Ontario air for this essentially blue-water cruiser. He backs down (after a quick rev to feather out the blades) far more effectively now. He stops far more rapidly. His docking is far more controlled. He can move his heavy, trad. keeled boat like a minivan now. It's quite interesting to see. Disadvantages: The cones in his transmission have been wearing far more quickly and have required replacement. He can handle this himself as a repair, so it's more an annoyance than a tragedy, and spares from Volvo are pricey. He figures that shifting the gears with a bigger, heavier prop is causing wear and tear beyond the engine spec. You can hear the "clunk" of his shifting outside the boat, actually. He is consulting with a marine engineer to determine a better course of action, but he is leaning towards a shock-absorbing coupler and a thrust bearing designed to isolate the engine transmission more effectively from the sheer inertia of this otherwise fine prop. Overall, he is so happy with the performance, however, both under sail and power, that he would consider getting a new diesel to make full use of the prop, rather than sticking with the small but still viable diesel that perhaps doesn't have the beef at the back end to cope with God's Own Feathering Prop G. Hope this little tale helps. R. |
rhys, hate to tell you this, but an Auto-Prop doesn't feather.
Still, the clown spent $3,500 Cdn, so you gotta expect him to tell you *something*. 20 miles a day is a 15% improvement on a base 5.6 knot cruising speed and you are correct that folding props make the most difference in light air. Reducing drag has the advantage over adding sail area in that it does not add to heeling moment. BTW, Gori, Martec, Brunton/Varifold and others make 3 blade folders. Volvo even makes a 4 bladed folder. Now, you can continue to rant and make an ass of yourself as usual but that is all I have to say about it. For what it's worth: Buddy of mine with a steel Wallstrom-designed (partner to Brewer) 1979 ketch popped for a three-bladed AutoProp, a feathering design. He had to haul out for many reasons: 1) to confirm the exact geometry of his hull around the shaft; 2) to cut back his rudder at that point for the install; and 3) to get the prop itself on. 1) was because it's essentially a custom casting, and NOT cheap (about $3,500 Cdn.). After three seasons now, he's happy as a clam with his decision and outlay. He says the following: Advantages: Bigger prop, better bite and power curve. He's got a 35 HP Volvo (probably 15-25 HP too small for a 28,000 lb. boat), but according to him, the power he transmits to the prop is greatly increased. His top speed without redlining has gone from 6.5 to 8.2 knots, or approximately hull speed. He says he gains 1/2 knot due to the self-feathering action, a significant gain in typical light Lake Ontario air for this essentially blue-water cruiser. He backs down (after a quick rev to feather out the blades) far more effectively now. He stops far more rapidly. His docking is far more controlled. He can move his heavy, trad. keeled boat like a minivan now. It's quite interesting to see. Disadvantages: The cones in his transmission have been wearing far more quickly and have required replacement. He can handle this himself as a repair, so it's more an annoyance than a tragedy, and spares from Volvo are pricey. He figures that shifting the gears with a bigger, heavier prop is causing wear and tear beyond the engine spec. You can hear the "clunk" of his shifting outside the boat, actually. He is consulting with a marine engineer to determine a better course of action, but he is leaning towards a shock-absorbing coupler and a thrust bearing designed to isolate the engine transmission more effectively from the sheer inertia of this otherwise fine prop. Overall, he is so happy with the performance, however, both under sail and power, that he would consider getting a new diesel to make full use of the prop, rather than sticking with the small but still viable diesel that perhaps doesn't have the beef at the back end to cope with God's Own Feathering Prop G. Hope this little tale helps. R. |
mmc, go away. you are a lying sack of squat trying to get people hurt. go
away. From: "MMC" Date: 8/29/2004 12:01 PM Eastern Daylight Time Message-id: What I understand from any of your postings is that you are incredibly insecure, misinformed, and HAVE to have the last word. My point was, Rosalie had performed her own test on drag with prop folded and unfolded and stated her results. You're pointing out that her prop was turning and creating drag really didn't support your fantasy position in this discussion. My fixed prop turns too, when in forward, reverse, or in idle and sailing. In fact, the only time it doesn't turn is when the boat is dockside. Amazing, huh? I've avoided responding to your posts for years, but couldn't when you lamely tried to make Rosalie look bad when all she was doing was participating in a discussion (which she understands better than you do). "JAXAshby" wrote in message ... uhhhhhhhh, mmc? which word didn't you understand? From: "MMC" Date: 8/28/2004 3:34 PM Eastern Daylight Time Message-id: Uh huh, and the point would be? "JAXAshby" wrote in message ... Rosalie, your prop was also turning while you were running the engine. that alone is one hell of a drag. "Paul L" wrote: You will definitely will see a decent speed improvement under sail with a folding prop. Depending on the prop you buy, you should see better power/control in reverse too. They are very reliable now, so I don't think that is a down side. The biggest downside is their cost. I have a Max prop and think it great. Paul www.jcruiser.org "MLapla4120" wrote in message ... I'm going to re-power soon and am also going to get new shaft and prop. It seems that in my boat class (Westsail 32), some people are going to folding props to help speed under sail. I'm for increased speed, but also want reliability. My current bronze propeller is pitted and old. Every time I turn around and look at it, it is full of sea growth. That makes me think I'm getting poor performance. So, I'm for an improvement, but I am unsure of what kind. Any opinions from boaters that have encountered this situation would be appreciated. We have a feathering prop (vs a folding prop) and we do get an increase of about 1/2 knot under sail, and it also backs better under power. I haven't tried to quantify the backing under power - it is just what we feel. Disadvantages are - you lose a bit of power forward because the blades are flat and the prop takes a bit more maintenance than a fixed prop. [We were sailing but had the engine on in neutral so the prop was not feathered - we were running the refrigeration- and when we had finished that, we turned off the engine and feathered the prop, and our speed increased 1/2 knot - same wind and current. Now I know this is not a completely scientific test, but it is significant to us. There are also people in our group who did tests with a fixed prop over a measured course, and then did the same tests with a folding prop over the same course and found a similar result.] grandma Rosalie |
now, THAT is an informed response.
"JAXAshby" wrote in message ... mmc, go away. you are a lying sack of squat trying to get people hurt. go away. |
On 30 Aug 2004 03:34:57 GMT,
JAXAshby wrote: rhys, hate to tell you this, but an Auto-Prop doesn't feather. The blades rotate until they are inline with the shaft axis, how is this not feathering? Still, the clown spent $3,500 Cdn, so you gotta expect him to tell you *something*. What would have done the job as well, for less money? -- Jim Richardson http://www.eskimo.com/~warlock 'Windows' really does make a fine swear word, representing all that's taboo and awful - just like '****', '****', etc." -- Mark Hughes, sdm |
paul, AC is a newbie who has been deliberately trying to harm people with his
nonsense posts. AC is the kind of person you tell to go pull a fake gun on a cop late at night. AC, has no value in any fashion. now, THAT is an informed response. "JAXAshby" wrote in message ... mmc, go away. you are a lying sack of squat trying to get people hurt. go away. |
The blades rotate until they are inline with the shaft axis, how is this
not feathering? take a look at the blades. they rotate and thus *reduce* drag, but they certainly don't "feather". |
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