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Old 05-02-2017, 11:48 AM   #1
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Rigging on davits

Ok this is driving me crazy . Why are these blocks twisting 90 degrees to each other ? I have swivels on each end . Do I need to remove one ? On the side that has the double block at the top the line wants to climb out of the sheave .
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Old 05-02-2017, 12:54 PM   #2
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lol, been there and just as confused until I realized what was happening. You have 2 sheeves up top, the load comes in from one side. On the top pulley in the stern of the dink the line comes in from the Davit towards the front of the dink, that is why it is tilted to the port of the big boat.
Purchase a 3 sheeve block and route the line symmetrical through the center one first.
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Old 05-02-2017, 01:05 PM   #3
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Also, on the blocks towards the bow of the dink, the top block is being pulled towards the starboard side of the dink. This means that the line leading down to the lower block is also being pulled to the starboard side. This is causing that lower block to rotate in that direction.
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Old 05-02-2017, 01:41 PM   #4
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Are you using a capstan or a sheet winch to hoist? If so once in a while you have to unreeve the lines and unwind them. Constantly turning in one direction under load makes the lines twist in clockwise fashion. If you have the chance, if this is on a capstan that powers in both directions wind it counterclockwise once in a while when hauling dinghy. Braided lines can get hockles in them contrary to conventional thinking.

It's not the blocks that have the issue. It's the line.
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Old 05-02-2017, 01:47 PM   #5
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Endlessly annoying to re-reeve blocks until they learn some manners. Been there, done that.
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Old 05-02-2017, 01:58 PM   #6
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The pick up points on the davits are about 12" closer together than the pick up points on the dink. I thought about making a spreader bar and attach it to the davits and get my pick up points at the same distance apart . Will this make the blocks stay in line and not twist 90 degrees from each other or can I fix it with more blocks . We are raising and lowering by hand .
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Old 05-02-2017, 02:16 PM   #7
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I don't think that would make a difference Marty. As was mentioned, you may want to check line twist, I had considered that, but unless it was pretty bad I don't think it would cause as much twisting as you are experiencing.

Those are nice wooden blocks, but if you want the twist to go away, you can always use a fiddle block.


These would eliminate the twist and you can get as much purchase as you like. The double fiddle block with becket above would go where your upper double block is on the stern. A single block with becket would go below it. That Lewmar block from Defender is only $38 and will take a 5/16" double braid line.

Or find someone like me with lots of old sailing gear in their basement and scrounge for it. The other option is if you have a chandlery in your area that caries used gear.
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Old 05-02-2017, 02:25 PM   #8
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This shows the difference in the distance between pick up points . The top block seems to splay more than the bottom and the position of the cleats on the davits is even closer . Once it starts to climb out of the sheave it's almost impossible to get the dink up as high as I want it . Joy is starting to loose interest in a nice dinghy ride .
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Old 05-02-2017, 03:00 PM   #9
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Since your problem is the upper block twisting out of line, the very first thing I would try is simply remove that swivel connecting the block to the davit arm. I can see no valid reason for that swivel being there in the first place!
You might at the same time gain a bit of extra lifting height, enabling you to snug the dinghy right up to the davits.

I have 4:1 purchase on my davit falls. I redesigned the rig a little to allow me to replace the upper block with a double, fixed cheek block. It does not swivel at all, of course, and I have no trouble with this arrangement.
So, taking the swivel out may solve your problem.
By the way, lovely dinghy! - what brand and model?
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Old 05-02-2017, 03:49 PM   #10
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Thanks for the suggestions everyone .

dhays I got those old blocks from our own FF right here on TF along with some heavy duty big bronze cleats .

SlowGypsy the dink is an older Trinka 10 ft .
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Old 05-02-2017, 04:53 PM   #11
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My davit mfr, Ocean Marine Systems Ocean Marine Systems - Davits, Rails, Lifts, and Platforms. insisted that my davit falls be out of line, like you have yours, so that the dink can be pulled up tight and have less inclination to flop around. He stated that the higher part of the load on the system is dynamic and that it's important to have the dink move as one with the boat.
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Old 05-02-2017, 05:03 PM   #12
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The swivels are not helping. The top blocks should just have a shackle. The bottom should just have the snap shackle. No swivels. The purpose of swivels under load is to let the load rotate. There is no need to let the dinghy rotate at all.

Since you pull this up by hand, do you lower it with a wrap around a cleat on both sides?

If so, when you make the line fast turn the first round turn of the line the opposite of the way you currently do. Running a line out under tension around a cleat puts twists in line also. (Same thing why anchor Rhodes get full of Hockles).
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Old 05-02-2017, 09:21 PM   #13
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The way I am taught to reeve blocks like your double set, is that they are supposed to be aligned at 90 degrees to each other.
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Old 05-02-2017, 09:34 PM   #14
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What was this line used for in its previous life? Is this an old anchor rhode? Or a roller furler line? Something that was constantly wrapped under tension on a winch?
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Old 05-03-2017, 06:41 AM   #15
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I think this was an old genoa sheet line from my
sailboat. Sounds like I probably need two new 7/16 " lines with thimbles so I don't have to tie it to the blocks , then remove at least one of the swivels from each side .
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Old 05-04-2017, 06:19 AM   #16
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Try rigging the falls differently .

Look in Chapmans
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Old 06-19-2017, 08:52 AM   #17
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I removed all four swivels . No binding or twisted lines now . I plan on buying some new line with a small eye splice in one end to hook to the blocks so I can get rid of the knot . Thanks for all the help . This made huge difference. The blocks are still canted some but the stay in line with each other .
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