I have a Harken lower block on my H18 thinking of replacing the upper seaway blocks . can you put a triple block on the upper or does the load need to be spread out on the boom ?
You can hang a triple block off of a single boom bale. Lot’s of folks have done this over the years (including myself).
That being said, the individual bales are not really angled perfectly to align with the lower block and this can stress the bale and eventually cause it to bend or crack. My recommendation would be to remove the middle bale, move it aft a couple inches and tilt it so it points slightly forward so the angle of the bale is in line with the angle of the blocks. Another thing you can also do is take off one of the extra bales and double it up with the middle bale. Basically “nest” the bottom of the bales together so the middle bale points down (as installed by the factory) and the extra bale angles forward with the bottoms of the two bales nested together. The shackle for your triple block passes through both bales. This doubles the connection strength to the boom.
what kind of hook did you use ? I was thinking of using a snap shackle on both ends to make it easy to take on and off ? and am I thinking right that factory is 7:1 since it has 3 blocks and the becket on top ? I was thinking triple 57mm classic block with becket but having hard time finding one I might have to go with the Carbo block to get triple with becket or back up to 6:1 move my triple to top and put double with becket on bottom ?
I like the idea of double bales and it would clean the boom up a bunch
would stainless rivets be good enough or do I need monel ?
Stock setup is 7:1. Personally I would (and do) just use standard bow shackles since they are highly dependable and there’s really no reason (at least for me) to remove the blocks from the boom. You may find that you need to limit the rotation of the upper block so the lines don’t get twisted. I achieved this by running a thin line, like 1/6” diameter, several times between the top of the center block and the boom bale. This lets the block swing about 90 degrees in either direction, but not a full 360.
You don’t absolutely need the upper block to be a triple with becket. If you don’t have a becket, you can just tie off to the forward (unused) boom bale. It’s not as clean as with the becket, but it works.
You don’t absolutely need the upper block to be a triple with becket. If you don’t have a becket, you can just tie off to the forward (unused) boom bale. It’s not as clean as with the becket, but it works.
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I did this using a Seaway triple from an old H18 (I disassembled the lower triple with ratchet and just used the block). Tied off the loose end to the rear boom bale, and hung the triple from the middle. I replaced the Seaway cleat on the bottom with Harken 150 (I think) cleat. This was a suggestion from Steve Murray at Murray's. He also sells the adapter plate needed to upgrade the cleats. The whole setup was cheap and I really like it over the stock setup.
Yes, it's a nice upgrade. I used the 3 inch classic harken 7:1 for years on my H18, recently upgraded to the carbo ratchet 8:1 but the original steel ones still work great.