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#11
posted to rec.boats
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Bimini top brackets
"John H" wrote in message ... On Sun, 4 Jan 2009 10:01:50 -0500, "Eisboch" wrote: "John H" wrote in message . .. What I'm looking for is some type of ball and socket bracket that would allow side to side motion without transmitting the stress to the screws. I think you'd end up with a very floppy bimini. The type of brackets you have allow the bimini to be lowered (folded up when underway). They are not supposed to hold it rigid. That's what the straps are for. Eisboch Agree. But the straps prevent forward and backward motion. It's rock solid that way. If there were straps going from the top right to the bottom left and vice versa, then the swaying motion would be stopped also, or at least most of it. But, walking around would be a pain. It looks like a combination of this: http://tacomarine.com/ccp51/media/im...y/F11-0177.gif and this: http://tacomarine.com/ccp51/media/im...l/F13-0301.gif may do the job. Maybe I don't understand your concept. What you have pictured is a ball and socket type of fitting that is *designed* to allow it to flop around. If your idea is to tighten up on the socket so it clamps down hard on the ball it might stiffen it up *however* all the forces due to wind, etc. will still be imparted on the bracket screws. You mentioned they are screws, not bolts with backing plates. IMO, you're going up with cracks in the gunnels. Too stiff is not always good. Wait, let me rephrase that. It's not always desirable to mount something like a wind catching bimini in a manner that it can't "give" a bit. All the forces will be transmitted to the brackets. The straps provide *additional* fore and aft support, taking much of the stress off the brackets. They are there with consideration that you may have the bimini up while underway. That's my opinion. Eisboch |
#12
posted to rec.boats
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Bimini top brackets
On Jan 4, 9:20*am, John H wrote:
On Sun, 04 Jan 2009 08:51:55 -0500, "Reginald P. Smithers III, Esq." wrote: John H wrote: The bimini top on my Key West uses a mounting like this" http://tinyurl.com/9ozwsy This bracket allows the frame member mounted therein to rotate from front to back without placing undue stress on the mounting screws. Note, I said screws, not through bolts. However when underway, even slowly, or just at anchor with a small amount of ripple in the water, the bimini top sways from side to side. The side to side motion gets transmitted directly to the screws in the brackets, and causes them to loosen. I'm sure it's just a matter of time before they strip or worse. I'm wondering if there aren't some fittings made that would have a ball socket or some such to allow complete forward and back movement *and* some degree of lateral movement. Anyone know of such a thing? Help! Is there a way to replace the screws with bolts and a backing plate? The current screw allows side to side motion, and some of the motion is absorbed by spring. *If you had a bracket that did not allow side to side motion, the fiberglass and screw would be taking all the stress directly and would actually strip quicker. *Or at least that is my story, and I am sticking to it. What I'm looking for is some type of ball and socket bracket that would allow side to side motion without transmitting the stress to the screws.- Hide quoted text - - Show quoted text - Impossible. If it were a ball and socket type of connection, then it would be free to rotate all the way to the ground or water. If it were limited somehow, then it would still put the same amount of stress on the screws when it reached that limit. |
#13
posted to rec.boats
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Bimini top brackets
John H wrote:
On Sun, 4 Jan 2009 10:01:50 -0500, "Eisboch" wrote: "John H" wrote in message ... What I'm looking for is some type of ball and socket bracket that would allow side to side motion without transmitting the stress to the screws. I think you'd end up with a very floppy bimini. The type of brackets you have allow the bimini to be lowered (folded up when underway). They are not supposed to hold it rigid. That's what the straps are for. Eisboch Agree. But the straps prevent forward and backward motion. It's rock solid that way. If there were straps going from the top right to the bottom left and vice versa, then the swaying motion would be stopped also, or at least most of it. But, walking around would be a pain. It looks like a combination of this: http://tacomarine.com/ccp51/media/im...y/F11-0177.gif and this: http://tacomarine.com/ccp51/media/im...l/F13-0301.gif may do the job. If I thought the bimini on a new boat would not hold up the stress while underway or even from waves, I would talk to my dealer about finding a better solution and/or providing backing plates and bolts. But as far as the brackets you showed, I don't think those would reduce the side to side movement, and would actually increase the movement. |
#14
posted to rec.boats
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Bimini top brackets
John H wrote:
On Sun, 04 Jan 2009 09:01:56 -0500, Jim wrote: John H wrote: The bimini top on my Key West uses a mounting like this" http://tinyurl.com/9ozwsy This bracket allows the frame member mounted therein to rotate from front to back without placing undue stress on the mounting screws. Note, I said screws, not through bolts. However when underway, even slowly, or just at anchor with a small amount of ripple in the water, the bimini top sways from side to side. The side to side motion gets transmitted directly to the screws in the brackets, and causes them to loosen. I'm sure it's just a matter of time before they strip or worse. I'm wondering if there aren't some fittings made that would have a ball socket or some such to allow complete forward and back movement *and* some degree of lateral movement. Anyone know of such a thing? Help! We need to reduce or eliminate the sway. What is the frame made of? Show a picture of the frame, set up with the canvas on it. I don't have any pictures with the bimini up. I think it's ugly. The frame is stainless steel. I could reduce the sway by using some bungee cords or straps *across* the boat, or to the center console. I've thought of that, but the straps would be in the way of walking around. As a last resort, that's what I'll do. I'm thinking there must be some mounting brackets *made* to allow side to side motion. I've just got to find them! Doesn't that swaying drive you crazy? |
#15
posted to rec.boats
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Bimini top brackets
On Sun, 4 Jan 2009 10:22:10 -0500, "Eisboch" wrote:
"John H" wrote in message .. . On Sun, 4 Jan 2009 10:01:50 -0500, "Eisboch" wrote: "John H" wrote in message ... What I'm looking for is some type of ball and socket bracket that would allow side to side motion without transmitting the stress to the screws. I think you'd end up with a very floppy bimini. The type of brackets you have allow the bimini to be lowered (folded up when underway). They are not supposed to hold it rigid. That's what the straps are for. Eisboch Agree. But the straps prevent forward and backward motion. It's rock solid that way. If there were straps going from the top right to the bottom left and vice versa, then the swaying motion would be stopped also, or at least most of it. But, walking around would be a pain. It looks like a combination of this: http://tacomarine.com/ccp51/media/im...y/F11-0177.gif and this: http://tacomarine.com/ccp51/media/im...l/F13-0301.gif may do the job. Maybe I don't understand your concept. What you have pictured is a ball and socket type of fitting that is *designed* to allow it to flop around. If your idea is to tighten up on the socket so it clamps down hard on the ball it might stiffen it up *however* all the forces due to wind, etc. will still be imparted on the bracket screws. You mentioned they are screws, not bolts with backing plates. IMO, you're going up with cracks in the gunnels. Too stiff is not always good. Wait, let me rephrase that. It's not always desirable to mount something like a wind catching bimini in a manner that it can't "give" a bit. All the forces will be transmitted to the brackets. The straps provide *additional* fore and aft support, taking much of the stress off the brackets. They are there with consideration that you may have the bimini up while underway. That's my opinion. Eisboch OK, my explanation probably sucked. I'm not worried about fore and aft motion, either while underway or at anchor. It's the side to side motion of the bimini that puts stress on the mounting bracket, because there is not enough play in the interface between the bimini frame and the deck bracket. The side to side motion gets transmitted through the bracket to the mounting screws. I don't want to stop the side to side motion. I want it to be free, so that stress will not be transmitted to the screws. I'm thinking the ball is loose in the socket, but I've not seen it yet. |
#17
posted to rec.boats
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Bimini top brackets
"Jim" wrote in message ... wrote: On Jan 4, 9:31 am, John H wrote: On Sun, 04 Jan 2009 09:01:56 -0500, Jim wrote: John H wrote: The bimini top on my Key West uses a mounting like this" http://tinyurl.com/9ozwsy This bracket allows the frame member mounted therein to rotate from front to back without placing undue stress on the mounting screws. Note, I said screws, not through bolts. However when underway, even slowly, or just at anchor with a small amount of ripple in the water, the bimini top sways from side to side. The side to side motion gets transmitted directly to the screws in the brackets, and causes them to loosen. I'm sure it's just a matter of time before they strip or worse. I'm wondering if there aren't some fittings made that would have a ball socket or some such to allow complete forward and back movement *and* some degree of lateral movement. Anyone know of such a thing? Help! We need to reduce or eliminate the sway. What is the frame made of? Show a picture of the frame, set up with the canvas on it. I don't have any pictures with the bimini up. I think it's ugly. The frame is stainless steel. I could reduce the sway by using some bungee cords or straps *across* the boat, or to the center console. I've thought of that, but the straps would be in the way of walking around. As a last resort, that's what I'll do. I'm thinking there must be some mounting brackets *made* to allow side to side motion. I've just got to find them!- Hide quoted text - - Show quoted text - Not sure but I would look into Sailboat hardware... Lot's of moving joints there, one might suit your needs.. Boom to mast hardware comes to mind. I don't think it's what he should be thinking about though. You talkin' about a 'gooseneck' fitting? fitting retracted for roller furling... http://smg.photobucket.com/albums/v2...t=Hpim0167.jpg fitting inserted for normal sailing..... http://smg.photobucket.com/albums/v2...t=Hpim0168.jpg |
#18
posted to rec.boats
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Bimini top brackets
On Sun, 04 Jan 2009 10:35:46 -0500, John H
wrote: OK, my explanation probably sucked. I'm not worried about fore and aft motion, either while underway or at anchor. It's the side to side motion of the bimini that puts stress on the mounting bracket, because there is not enough play in the interface between the bimini frame and the deck bracket. The side to side motion gets transmitted through the bracket to the mounting screws. "Side to side" motion is the most difficult to prevent because there is typically no lateral bracing. The screws are working loose because of the high stress on them, and they will crack the deck eventually as others have pointed out. The answer is to through bolt the fittings with backing plates and/or oversize fender washers. That will solve the fitting problem and may reduce swaying some what. Ultimately the answer is more bracing, with at least three attachment points on each side. I'd get the recomendation of a good canvas shop that does a lot of biminis. |
#19
posted to rec.boats
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Bimini top brackets
On Sun, 04 Jan 2009 08:43:17 -0500, John H
wrote: The bimini top on my Key West uses a mounting like this" http://tinyurl.com/9ozwsy This bracket allows the frame member mounted therein to rotate from front to back without placing undue stress on the mounting screws. Note, I said screws, not through bolts. However when underway, even slowly, or just at anchor with a small amount of ripple in the water, the bimini top sways from side to side. The side to side motion gets transmitted directly to the screws in the brackets, and causes them to loosen. I'm sure it's just a matter of time before they strip or worse. I'm wondering if there aren't some fittings made that would have a ball socket or some such to allow complete forward and back movement *and* some degree of lateral movement. Anyone know of such a thing? Help! The only way you are going to stop it is to make the stainless tubing fairly rigid - it's not so much the movement in the mount as it is the length of the tubing that is causing your problem. And the only way to stop that is to use heavier wall tubing - it's the wall flex that's the problem, not the mount. Cheap T-tops have the same problem - not enough wall strength in the tubes to make it rigid so they cross brace the hell out of them. Even in custom made, heavy T-tops like mine move without cross bracing. This T-top is very similar to mine - mine is a little taller, made from thicker tubing and is a slightly different design, but the point is that it's cross braced to keep the sway down. http://www.rangerboats.com/flash/gal...id=5511&gid=38 This is mine. http://www.swsports.org/images/Pictu...g%20Boat02.jpg With your current setup, the only way to make it stop is to cross brace the tubing with some sort of cording - maybe bungee cord or similar. What I would do is brace the cornors of the top where the tubing bends. You might be able to do it with bungee cord, but that defeats the purpose - it would cut down on the sway though. -- "An idealist is one who, on noticing that a rose smells better than a cabbage, concludes that it will also make better soup." H.L. Mencken |
#20
posted to rec.boats
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Bimini top brackets
On Sun, 04 Jan 2009 12:03:49 -0500, wrote:
On Sun, 04 Jan 2009 08:43:17 -0500, John H wrote: The bimini top on my Key West uses a mounting like this" http://tinyurl.com/9ozwsy This bracket allows the frame member mounted therein to rotate from front to back without placing undue stress on the mounting screws. Note, I said screws, not through bolts. However when underway, even slowly, or just at anchor with a small amount of ripple in the water, the bimini top sways from side to side. The side to side motion gets transmitted directly to the screws in the brackets, and causes them to loosen. I'm sure it's just a matter of time before they strip or worse. I'm wondering if there aren't some fittings made that would have a ball socket or some such to allow complete forward and back movement *and* some degree of lateral movement. Anyone know of such a thing? Help! You need some diagonal bracing to stop the side to side. I see folks with straps from the top corner to the opposite gunnel. Yeah, that's one solution, but then walking around gets to be a big PITA. |
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