Greetings! Recently our mast was run over by a semi. Don't ask. Anyway, one of the spreader brackets is bent and I don't know which one. One is basically perpendicular to the mast and the other angled up at 10-20 degrees. Which one is correct for a 1980 Hunter 33? Thanks! Garry Elmer Mystic, CT http://www.99main.com/~elmergw/
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Tim Schaaf
angles up
Sorry about your mast! Spreaders are designed to bisect the angle of the shroud they carry. In a single spreader rig such as ours, the only shroud carried by the spreader is the upper. Thus, it should cant upwards at an angle that will bisect the angle of the shroud at its tip. I haven't measured the exact angle (you could calculate it), but since it cannot be perpendicular to the mast, I assume the other is correct. Providing, of course, that the wayward semi did, in fact, leave it unscathed. Our spreaders are not angled back, either, like the B&R spreaders are. Good luck.
Sorry about your mast! Spreaders are designed to bisect the angle of the shroud they carry. In a single spreader rig such as ours, the only shroud carried by the spreader is the upper. Thus, it should cant upwards at an angle that will bisect the angle of the shroud at its tip. I haven't measured the exact angle (you could calculate it), but since it cannot be perpendicular to the mast, I assume the other is correct. Providing, of course, that the wayward semi did, in fact, leave it unscathed. Our spreaders are not angled back, either, like the B&R spreaders are. Good luck.
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Ken Palmer
What????
Every H33 I have seen has the spreaders 90 degrees to the mast. Tim, did I misunderstand your post? Ken Palmer, S/V Liberty 1981 H33
Every H33 I have seen has the spreaders 90 degrees to the mast. Tim, did I misunderstand your post? Ken Palmer, S/V Liberty 1981 H33
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Tim Schaaf
Ken, no misunderstanding
The spreaders on any mast should bisect the angle of the shroud. On a single spreader rig, since the shroud angles in from the spreader to the masthead, the spreader MUST angle up somewhat. Otherwise, the load of the shroud will have the effect of trying to force the spreader further out of place, which can cost you your spreader and your mast! If the spreader is angled properly, all of its load is purely in compression, which is what it is designed for. I hope all of those 33's you mentioned don't actually have their spreaders perpendicular to the mast.......none that I have seen do, but, to be honest, I have only looked at a few other than mine. If you would like a more detailed explanation, write, or ask your rigger.
The spreaders on any mast should bisect the angle of the shroud. On a single spreader rig, since the shroud angles in from the spreader to the masthead, the spreader MUST angle up somewhat. Otherwise, the load of the shroud will have the effect of trying to force the spreader further out of place, which can cost you your spreader and your mast! If the spreader is angled properly, all of its load is purely in compression, which is what it is designed for. I hope all of those 33's you mentioned don't actually have their spreaders perpendicular to the mast.......none that I have seen do, but, to be honest, I have only looked at a few other than mine. If you would like a more detailed explanation, write, or ask your rigger.
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Tim Schaaf
More on spreaders
Ken, re-reading Garry's post, I note that his options were 90 degrees and bent up at "10 to 20 degrees". 20 is clearly way too much, and I haven't done the math but 10 seems a bit much as well. So neither of his choices may be correct. He may have started with right angles on both ( which is incorrect) and then bent one up by 20 degrees!!! Anyway, if he bisects the angle, he will have it right.
Ken, re-reading Garry's post, I note that his options were 90 degrees and bent up at "10 to 20 degrees". 20 is clearly way too much, and I haven't done the math but 10 seems a bit much as well. So neither of his choices may be correct. He may have started with right angles on both ( which is incorrect) and then bent one up by 20 degrees!!! Anyway, if he bisects the angle, he will have it right.
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Ken Palmer
My mast.
Every year I unstep and step my own mast on my H33. When I store the mast, either on a rack or on the boat, I remove the spreaders from the mast. The studs that the spreaders slide over appear to be 90 degrees to me. I guess the only way I will know for sure is to go out to the club and measure the angle. Maybe this weekend if spring decides to finally arrive in Rochester. I have been known to be wrong before <g>. By the way, I am not questioning the theory of it all, just an answer to the original question by Gary. Ken Palmer, S/V Liberty
Every year I unstep and step my own mast on my H33. When I store the mast, either on a rack or on the boat, I remove the spreaders from the mast. The studs that the spreaders slide over appear to be 90 degrees to me. I guess the only way I will know for sure is to go out to the club and measure the angle. Maybe this weekend if spring decides to finally arrive in Rochester. I have been known to be wrong before <g>. By the way, I am not questioning the theory of it all, just an answer to the original question by Gary. Ken Palmer, S/V Liberty
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Terry Arnold
spreader angle
I'm jumping in this spreader thing because my 79 H33 mast is presently disassembled and just down at my barn so I went and looked at it. I measured the bracket and the tab (which the spreader is inserted over) is angled off square (upward) by about 5/16" in the tab height of 2 1/2". this would give an angle of about 7.1 degrees. I will posted a photo in the photo forum to make this a little clearer.
I'm jumping in this spreader thing because my 79 H33 mast is presently disassembled and just down at my barn so I went and looked at it. I measured the bracket and the tab (which the spreader is inserted over) is angled off square (upward) by about 5/16" in the tab height of 2 1/2". this would give an angle of about 7.1 degrees. I will posted a photo in the photo forum to make this a little clearer.
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Tim Schaaf
Hi Ken
Last night I looked at my spreaders (the mast is up so I did it from the dock) and guess that Terry's numbers are pretty close to mine. And, if I were not careful with the angle from which I looked, I could easily have mistaken them for being "square", but they actually are not. Our shroud angles are actually pretty narrow, so the angle that is bisected is not that great.
Last night I looked at my spreaders (the mast is up so I did it from the dock) and guess that Terry's numbers are pretty close to mine. And, if I were not careful with the angle from which I looked, I could easily have mistaken them for being "square", but they actually are not. Our shroud angles are actually pretty narrow, so the angle that is bisected is not that great.
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Ken Palmer
A picture is worth...
A thousand words. Great job with the camera. I think that as time goes on, you will see more and more images to back-up some of the posts we read about. I took a series of photos last year when I removed the teak trim near the cabin-top of my H33, Liberty. Had to pull the teak plugs (or whatever they are called) to get to the screws. Never did post them though. Maybe I should also take a couple shots on my method of rolling VC-17 to reduce evaporation. Ken Palmer, S/V Liberty (Let's try that new link to my Web site.)
A thousand words. Great job with the camera. I think that as time goes on, you will see more and more images to back-up some of the posts we read about. I took a series of photos last year when I removed the teak trim near the cabin-top of my H33, Liberty. Had to pull the teak plugs (or whatever they are called) to get to the screws. Never did post them though. Maybe I should also take a couple shots on my method of rolling VC-17 to reduce evaporation. Ken Palmer, S/V Liberty (Let's try that new link to my Web site.)
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Ken Palmer
Mr Schaaf is right.
I think Terry may have got it right too. The bugbear about this issue, even from one who has seen these boats actually designed and built, is that whatever the exact angle is by a protractor doesn't even matter. I know that sounds stupid, but as Tim Schaaf points out, the idea is to bisect the upper-shroud-- in fact it MUST bisect the angle of the shroud and anything else is unlikely if not impossible. The 7.1-degree angle is probably close to right, but the point is: don't force them to be anything they don't want to be. Tuning the rig correctly (and gently at first) will cause the spreaders to tend towards the correct position even if you didn't mount them that way. In theory it's a certainty of geometry. Forcing them to hold some other angle will result in the wrong stresses being related to the spar and MAY lead to rig failure (which will only ever happen when you have to pray it won't). If your spreaders are level with the water or what my dad called 'dog-eared' (down-angled) they are most defintely WRONG-- unless of course your boat is upside-down!! Also- spreaders on most yachts without induced mast rake (i.e., designed-in) should be more or less in line with the spar. Mast rake necessitates them being swept back. They should NEVER be swept forward-- this relates the wrong stress to the spar which again can cause failure. (BTW- The Bergstrom rig as on the new little 24 is theoretically supposed to have a back-angle of 30 degrees past athwartships-- thus creating three legs 120 degrees apart of the spar and two shroud points-- but I don't think Hunter imposed that much angle, to allow the main boom to swing out farther, and on a small boat like that it's not likely one will ever realise the full mathematical limitation of the stress loads of a lesser angle. It's probably more like 15 degrees.) J Cherubini II Cherubini Art & Nautical Design Org. JComet@aol.com
I think Terry may have got it right too. The bugbear about this issue, even from one who has seen these boats actually designed and built, is that whatever the exact angle is by a protractor doesn't even matter. I know that sounds stupid, but as Tim Schaaf points out, the idea is to bisect the upper-shroud-- in fact it MUST bisect the angle of the shroud and anything else is unlikely if not impossible. The 7.1-degree angle is probably close to right, but the point is: don't force them to be anything they don't want to be. Tuning the rig correctly (and gently at first) will cause the spreaders to tend towards the correct position even if you didn't mount them that way. In theory it's a certainty of geometry. Forcing them to hold some other angle will result in the wrong stresses being related to the spar and MAY lead to rig failure (which will only ever happen when you have to pray it won't). If your spreaders are level with the water or what my dad called 'dog-eared' (down-angled) they are most defintely WRONG-- unless of course your boat is upside-down!! Also- spreaders on most yachts without induced mast rake (i.e., designed-in) should be more or less in line with the spar. Mast rake necessitates them being swept back. They should NEVER be swept forward-- this relates the wrong stress to the spar which again can cause failure. (BTW- The Bergstrom rig as on the new little 24 is theoretically supposed to have a back-angle of 30 degrees past athwartships-- thus creating three legs 120 degrees apart of the spar and two shroud points-- but I don't think Hunter imposed that much angle, to allow the main boom to swing out farther, and on a small boat like that it's not likely one will ever realise the full mathematical limitation of the stress loads of a lesser angle. It's probably more like 15 degrees.) J Cherubini II Cherubini Art & Nautical Design Org. JComet@aol.com
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