It's a good time of the year to think about some of the oddities associated with my 37c. Since I've owned "Moonshine," I've been perplexed that the mast spreaders seem to point a bit forward rather than aft. This suggests that as the shrouds are tightened, the mast would tend to be bowed aft. I assume that this is intended to counteract forward pull on the mast exerted by the baby stay. I'd appreciate knowing if other 37c owners have the same situation, or if the spreaders on my mast were perhaps installed the day after after the 1979 holiday party. Second question relates to the prop shaft extending about 6 inches past the cutless. Boatyard folks say no more than one shaft diameter is called for, but I've seen other 36-37 ft Hunters with about 6 inches. I haven't had problems, but I'm curious if others may have. Looking forward to your replies. Happy Holidays. Capt. Walt.
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Gene Gruender
Soreaders and prop shaft
My spreaders on my '81 H37C point straight out to the side. I don't think what you are describing is normal. About the prop shaft - when I had a new one made due to the coupler working loose, I asked the machinist about making it about 6" longer so that I could remachine that end and use it again if I ever had another problem. He said that I didn't want to do that, because with it sticking out that much, if I ever got a line in it the extra leverage would easily bend it. I have about 2" on mine and it seems to work fine. I can't imagine why the difference between "one shaft diameter" and 2" would make much difference.
My spreaders on my '81 H37C point straight out to the side. I don't think what you are describing is normal. About the prop shaft - when I had a new one made due to the coupler working loose, I asked the machinist about making it about 6" longer so that I could remachine that end and use it again if I ever had another problem. He said that I didn't want to do that, because with it sticking out that much, if I ever got a line in it the extra leverage would easily bend it. I have about 2" on mine and it seems to work fine. I can't imagine why the difference between "one shaft diameter" and 2" would make much difference.
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Ed Schenck
Shaft length.
Walt, is this six inches between the strut and the prop? Or is it six inches from the strut to the very end of the shaft? Six inches including the prop would be about right I think. But the prop with six inches of shaft between it and the strut would not be good. In fact it wouldn't work on my boat with a folding prop. Agree with Gene, my spreaders look straight to me.
Walt, is this six inches between the strut and the prop? Or is it six inches from the strut to the very end of the shaft? Six inches including the prop would be about right I think. But the prop with six inches of shaft between it and the strut would not be good. In fact it wouldn't work on my boat with a folding prop. Agree with Gene, my spreaders look straight to me.
Backwards spreaders
Walt, do I correctly assume that you believe the mast has never been taken out of your boat since new? It sounds to me like the spreaders could have been put in backwards. Most two-pin spreaders have their mounting holes slightly staggered– it facilitates aft cant to the spreaders and also mast rake which is typical of anything my father drew. The spreaders should be at worst dead athwartships, but since what you describe suggests that the spreaders must have staggered holes, they may well be on backwards (I can't tell if upside-down too). The mast, too, should NEVER be perfectly plumb vertical but (and I have to guess without the hard data in front of me) raked about 10-16 degress aft. You cannot always rely on dorks on yard Travelifts when the boat is being recommissioned– sadly some marina help can have startlingly little knowledge of what a sailboat rig needs or wants and seek only to get you out of there and get themselves paid. The one thing I do know is that the inner forestay could not be exerting any incorrect moment if the rig were tuned right. The after lowers being too tight would only draw the spreaders forward if the rest of the rig were not tuned right. It sounds to me like the inner forestay itself may be too tight– but merely loosening that alone will NOT fix the problem. Get the rig examined by an experienced expert yacht rigger, designer/sailor, or sailmaker ASAP, and don't rule out removing and inspecting the spreaders themselves. Walt, you are not the only one to have rig tuning confusion and/or questions. But there is no reason (or excuse) to tolerate purple notes in your boat's rig. When a sailor is educated in rig tuning the chore can be no more alien than a musician's tuning a guitar– and as with a guitar player one will know by the results when he has got it right. J Cherubini II
Walt, do I correctly assume that you believe the mast has never been taken out of your boat since new? It sounds to me like the spreaders could have been put in backwards. Most two-pin spreaders have their mounting holes slightly staggered– it facilitates aft cant to the spreaders and also mast rake which is typical of anything my father drew. The spreaders should be at worst dead athwartships, but since what you describe suggests that the spreaders must have staggered holes, they may well be on backwards (I can't tell if upside-down too). The mast, too, should NEVER be perfectly plumb vertical but (and I have to guess without the hard data in front of me) raked about 10-16 degress aft. You cannot always rely on dorks on yard Travelifts when the boat is being recommissioned– sadly some marina help can have startlingly little knowledge of what a sailboat rig needs or wants and seek only to get you out of there and get themselves paid. The one thing I do know is that the inner forestay could not be exerting any incorrect moment if the rig were tuned right. The after lowers being too tight would only draw the spreaders forward if the rest of the rig were not tuned right. It sounds to me like the inner forestay itself may be too tight– but merely loosening that alone will NOT fix the problem. Get the rig examined by an experienced expert yacht rigger, designer/sailor, or sailmaker ASAP, and don't rule out removing and inspecting the spreaders themselves. Walt, you are not the only one to have rig tuning confusion and/or questions. But there is no reason (or excuse) to tolerate purple notes in your boat's rig. When a sailor is educated in rig tuning the chore can be no more alien than a musician's tuning a guitar– and as with a guitar player one will know by the results when he has got it right. J Cherubini II
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Walt Golembewski
spreaders and shafts
Thank you all for your helpful comments. John, regarding mast and spreaders: I've had the mast out several times over the past 6 years, as I've been unstepping the mast for winter storage (except for this year). I re-tune the rigging myself, generally using the procedures recommended by Hunter in its "operating manual" for this boat, which I was fortunately able to get from Hunter some years back. With the mast stepped and with no tension on the shrouds or stays (i.e., just with slack taken up), and with the main chainplate visually lined up with the base of the mast, if you were to look upward you would see that the spreader tips are canted a few inches forward. So it's doesn't appear to be rig tension that's the problem. Without any tension, the spreaders definitely cant forward. I, too, thought that the spreader fittings might have been installed backwards, and tried switching them. But the holes don't line up when port and aft spreader mounts are switched. And I they can't be just flopped upside down, since the spreader mounts have a slight upward cant to them, and flopping them upside down would make the spreaders point downwards. In general, when I tune the rig Itune it with less aft rake to the mast than one commonly sees on boats, but the 37c mast cross section is pretty hefty, and I never felt comfortable pulling the tip of the mast too far aft. But if I did, then the spreader tips would better line up with the mast as sighted from the side. Maybe I'll try this during the upcoming season. In spite of all of this, the good news is that the boat performs well on all points of sail -- at least by my cruising standards. The spreaders just look strange -- sort of like the tail on a Mooney if you're used to looking at Cessnas. I might try giving Hunter a call -- maybe a few of the folks who assembled these boats in the 79 time frame are still around. Thanks again for the info.
Thank you all for your helpful comments. John, regarding mast and spreaders: I've had the mast out several times over the past 6 years, as I've been unstepping the mast for winter storage (except for this year). I re-tune the rigging myself, generally using the procedures recommended by Hunter in its "operating manual" for this boat, which I was fortunately able to get from Hunter some years back. With the mast stepped and with no tension on the shrouds or stays (i.e., just with slack taken up), and with the main chainplate visually lined up with the base of the mast, if you were to look upward you would see that the spreader tips are canted a few inches forward. So it's doesn't appear to be rig tension that's the problem. Without any tension, the spreaders definitely cant forward. I, too, thought that the spreader fittings might have been installed backwards, and tried switching them. But the holes don't line up when port and aft spreader mounts are switched. And I they can't be just flopped upside down, since the spreader mounts have a slight upward cant to them, and flopping them upside down would make the spreaders point downwards. In general, when I tune the rig Itune it with less aft rake to the mast than one commonly sees on boats, but the 37c mast cross section is pretty hefty, and I never felt comfortable pulling the tip of the mast too far aft. But if I did, then the spreader tips would better line up with the mast as sighted from the side. Maybe I'll try this during the upcoming season. In spite of all of this, the good news is that the boat performs well on all points of sail -- at least by my cruising standards. The spreaders just look strange -- sort of like the tail on a Mooney if you're used to looking at Cessnas. I might try giving Hunter a call -- maybe a few of the folks who assembled these boats in the 79 time frame are still around. Thanks again for the info.
J
John Reid
Spreader / Prop shaft
Walt, -- I looked at my spreaders this morning, and they are very slightly angled forward; I'd guess that the tips are about 1/2" forward. Just coincidentally, my neighbors' boat is also an H37c and their spreaders look the same. -- I replaced my prop shaft last year. My original shaft was the same as yours; stuck out about six inches beyond the prop strut. The yard that did the work made the same recommendation as yours; that the shaft protrude no more than a distance about equal the shaft diameter. Made sense to me in terms of putting less force on the prop strut (which had worked loose with the old prop). A year later with the shorter shaft, the prop strut has stayed nice and snug. I do have one problem, though, that MAY be associated with the shorter shaft. I put an Autoprop on the boat at the same time. When motoring at cruising speed, the boat wants to pull to port. I've had the prop checked and its blades are changing angles are they are supposed to, and the prop is on at a clean angle. Looks to me that the problem is caused by the relatively small clearance (about an inch) between the ends of the prop blades and the hull, and I think I'm getting some prop-to-hull turbulence. That clearance would be better (bigger) obviously if the prop shaft were longer, since the shaft is angled down (away from the hull). I'm no engineer, but I think I've eliminated everything else. The boat sails straight as an arrow and balances easily, and at cruising RPMS (2000-2100) it moves along nicely at 5.9 - 6 knots (in calm conditions). Cheers, John Reid Cheese 'n Crackers john.patti.reid@juno.com
Walt, -- I looked at my spreaders this morning, and they are very slightly angled forward; I'd guess that the tips are about 1/2" forward. Just coincidentally, my neighbors' boat is also an H37c and their spreaders look the same. -- I replaced my prop shaft last year. My original shaft was the same as yours; stuck out about six inches beyond the prop strut. The yard that did the work made the same recommendation as yours; that the shaft protrude no more than a distance about equal the shaft diameter. Made sense to me in terms of putting less force on the prop strut (which had worked loose with the old prop). A year later with the shorter shaft, the prop strut has stayed nice and snug. I do have one problem, though, that MAY be associated with the shorter shaft. I put an Autoprop on the boat at the same time. When motoring at cruising speed, the boat wants to pull to port. I've had the prop checked and its blades are changing angles are they are supposed to, and the prop is on at a clean angle. Looks to me that the problem is caused by the relatively small clearance (about an inch) between the ends of the prop blades and the hull, and I think I'm getting some prop-to-hull turbulence. That clearance would be better (bigger) obviously if the prop shaft were longer, since the shaft is angled down (away from the hull). I'm no engineer, but I think I've eliminated everything else. The boat sails straight as an arrow and balances easily, and at cruising RPMS (2000-2100) it moves along nicely at 5.9 - 6 knots (in calm conditions). Cheers, John Reid Cheese 'n Crackers john.patti.reid@juno.com
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Walt G.
Prop Walk
John, Thanks for the input regarding spreader angle. FYI, in doing some further research on the topic, I came across one rig tuning manual that refers to forward angled spreaders, with the effect being to stiffen the mast. So perhaps the slightly forward cant was an intentional design feature of the 37c for reasons of stiffness. As I mentioned in an earlier post, I haven't been tuning in much mast prebend or aft rake, and perhaps the forward cant won't be as noticeable when I re-tune with some prebend and aft rake this spring. Regarding your prop walk to port under power: my 37c with a 2 blade prop also exhibits this in forward, with increased walk as power is increased. The same thing happens in reverse, but with tendency of the stern to walk to port. My guess is that in forward, it is a function of the prop shaft angle and unequal loading of the prop (port/stbd)due to the shaft and propeller angle to relative water flow. I know that the same sort of thing occurs in propeller driven aircraft due in part to unequal prop loading, with the turning tendency most noticeable at low speeds and high power. In reverse, I think it's a function of unequal prop loading and propwash against the hull. I've pretty much gotten to ignore the walk in forward, and just plan for the walk in reverse. Thanks again for your info. Capt. Walt s/v Moonsine
John, Thanks for the input regarding spreader angle. FYI, in doing some further research on the topic, I came across one rig tuning manual that refers to forward angled spreaders, with the effect being to stiffen the mast. So perhaps the slightly forward cant was an intentional design feature of the 37c for reasons of stiffness. As I mentioned in an earlier post, I haven't been tuning in much mast prebend or aft rake, and perhaps the forward cant won't be as noticeable when I re-tune with some prebend and aft rake this spring. Regarding your prop walk to port under power: my 37c with a 2 blade prop also exhibits this in forward, with increased walk as power is increased. The same thing happens in reverse, but with tendency of the stern to walk to port. My guess is that in forward, it is a function of the prop shaft angle and unequal loading of the prop (port/stbd)due to the shaft and propeller angle to relative water flow. I know that the same sort of thing occurs in propeller driven aircraft due in part to unequal prop loading, with the turning tendency most noticeable at low speeds and high power. In reverse, I think it's a function of unequal prop loading and propwash against the hull. I've pretty much gotten to ignore the walk in forward, and just plan for the walk in reverse. Thanks again for your info. Capt. Walt s/v Moonsine
Mast rake, and my typo (from H-27 'Mast Rake')
I accidentally made an egregious error in these boards about mast rake and have to clarify that I confused myself. I suggested 10-16 degrees of mast rake on about a 30-footer. This is WAY wrong– I meant 10-16 inches, measured at the masthead (about 5 degrees? –not doing trig here). Tie a plumb-bob to the topping lift, drop it to the deck, and measure how far back it lies from the aft edge of the mast (discard an inch or so for the masthead sheave). If the plumb-bob is bumping the back edge of the mast or even within about 4 inches you are WAY OFF. My dad's boats are all noted for mast rake. In fact some of them will look downright 'rakish' in profile. Our Cherubini 44 cutter had a J (foot of foretriangle) of about 20 feet from the end of the bowsprit and I swear you'd measure that mast rake in yards. It must have been about 6 ft on a 56-ft hoist. It resembled his 31-ft yawl of 1961 which has 1:16 rast rake– 2 ft for a 32-ft hoist. But no Hunter is going to be THAT raked. Mast rake is sort of a cheater way of inducing weather helm. The standard plain-Jane cruising boat will have its centre of effort (sail plan) about 15 percent of the waterline FORWARD of the centre of lateral resistance (underbody). This would suggest that the boat would have a severe lee helm. But the forward momentum as provided by the wind and the airfoil shape of the keel actually works to fool the design of the boat. That momentum sort of carries the boat straight through the forward difference between CE and CLR and it's like the boat becomes more interested in moving forward than bearing off. The CE is determined from the standing-still rig of the boat, what we should call the designed sail plan. Mast rake is already designed into that. The problem I believe many Hunter owners are having is that they have had their rigs tuned with the mast too vertical. If the mast rake specificaion is included in the forward justification of the CE, tuning the mast too vertical will actually spoil the boat's intended balance and further exaggerate that 15-percent-of-waterline difference. You will in effect have induced lee helm, sort of as if you've let the jib luff or not even put it up at all. There is logically no way you will be able to point well like that. Drawing the masthead aft will return these ill-tuned boats to a weatherish tendency and then all you'll have to worry about on the wind is keeping tell-tales parallel and jib lead position and leach tension and other fun stuff like that. Actually it is safe for all boats to have more weather helm than lee helm anyway. It is a sort of natural homing instinct that can help in emergencies, heavy weather, anchoring, and finding your bearings. If boats did not have a designed-in tendency to come into the wind you would never be able to come about! -or make your way home. I tend to suggest to people to lower their boom goosenecks and even have the mainsails recut to be 6-8 inches lower than I do to increase jib sizes. We get so rah-rah about headsails being leading edges and airfoils that we forget that the mainsail is the real power plant on most boats. Preserving mast rake will help the main do its real job fairly. JC II
I accidentally made an egregious error in these boards about mast rake and have to clarify that I confused myself. I suggested 10-16 degrees of mast rake on about a 30-footer. This is WAY wrong– I meant 10-16 inches, measured at the masthead (about 5 degrees? –not doing trig here). Tie a plumb-bob to the topping lift, drop it to the deck, and measure how far back it lies from the aft edge of the mast (discard an inch or so for the masthead sheave). If the plumb-bob is bumping the back edge of the mast or even within about 4 inches you are WAY OFF. My dad's boats are all noted for mast rake. In fact some of them will look downright 'rakish' in profile. Our Cherubini 44 cutter had a J (foot of foretriangle) of about 20 feet from the end of the bowsprit and I swear you'd measure that mast rake in yards. It must have been about 6 ft on a 56-ft hoist. It resembled his 31-ft yawl of 1961 which has 1:16 rast rake– 2 ft for a 32-ft hoist. But no Hunter is going to be THAT raked. Mast rake is sort of a cheater way of inducing weather helm. The standard plain-Jane cruising boat will have its centre of effort (sail plan) about 15 percent of the waterline FORWARD of the centre of lateral resistance (underbody). This would suggest that the boat would have a severe lee helm. But the forward momentum as provided by the wind and the airfoil shape of the keel actually works to fool the design of the boat. That momentum sort of carries the boat straight through the forward difference between CE and CLR and it's like the boat becomes more interested in moving forward than bearing off. The CE is determined from the standing-still rig of the boat, what we should call the designed sail plan. Mast rake is already designed into that. The problem I believe many Hunter owners are having is that they have had their rigs tuned with the mast too vertical. If the mast rake specificaion is included in the forward justification of the CE, tuning the mast too vertical will actually spoil the boat's intended balance and further exaggerate that 15-percent-of-waterline difference. You will in effect have induced lee helm, sort of as if you've let the jib luff or not even put it up at all. There is logically no way you will be able to point well like that. Drawing the masthead aft will return these ill-tuned boats to a weatherish tendency and then all you'll have to worry about on the wind is keeping tell-tales parallel and jib lead position and leach tension and other fun stuff like that. Actually it is safe for all boats to have more weather helm than lee helm anyway. It is a sort of natural homing instinct that can help in emergencies, heavy weather, anchoring, and finding your bearings. If boats did not have a designed-in tendency to come into the wind you would never be able to come about! -or make your way home. I tend to suggest to people to lower their boom goosenecks and even have the mainsails recut to be 6-8 inches lower than I do to increase jib sizes. We get so rah-rah about headsails being leading edges and airfoils that we forget that the mainsail is the real power plant on most boats. Preserving mast rake will help the main do its real job fairly. JC II
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