Author Topic: No name swivel blocks -beware.  (Read 195 times)

Offline Aldebaran_III

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No name swivel blocks -beware.
« on: April 21, 2017, 11:55:02 AM »
Just a heads up to check your blocks. All of the blocks on my HC (except mainsheet control)are unmarked swivel blocks as in the photos.
I've now had two of these fail under way. Luckily the ones that failed did not result in anything crashing all the way to the deck, but I did have to stop, lower the sail and make a temporary repair.
The problem is that all the load on the block is taken by that small threaded screw. The boat is 4 years old and used year round in warm salt water. The stainless screw is probably not the best quality and has given way.
I'm now replacing the most heavily loaded ones with Harken big bullet blocks. Not all the blocks really need to be swivel blocks. For instance the main halyard block on the mast can sometimes flip 180 degrees so that the sail won't go all the way up. In a case like that I used a Harken #146 http://www.harken.com/search.aspx?s=146 . Where a swivel block is really needed I used the #168 http://www.harken.com/search.aspx?s=168
These new blocks are full ball bearing blocks, so I'm hoping for easier hoisting and trimming as well as better reliability. I'll probably replace all the blocks as finances allow.

Cheers, Derek

Offline rbh1515

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Re: No name swivel blocks -beware.
« Reply #1 on: April 21, 2017, 08:46:33 PM »
Derek,
Great info!  I sail on Lake Michigan (Salt Free!), so I may not have any problems, but I'm going to go ahead and order those blocks.  I've had problems with that main halyard block flipping.  Can't go wrong with Harken....great Wisconsin company!
My boat goes in tomorrow..weather in Wisconsin is getting nice.
Rob
2015 Horizon Day Cat, Waters End

Offline Aldebaran_III

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Re: No name swivel blocks -beware.
« Reply #2 on: April 23, 2017, 05:01:21 PM »
Good chance your blocks are OK. Salt is the real killer, especially with lower grades of stainless hardware.
Enjoy your pure H2O sailing.
We went out today, reefed right down, but gave up after a short while. Too gusty and shifty, danger of crash gybes and maybe breaking something.
Derek

Offline rbh1515

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Re: No name swivel blocks -beware.
« Reply #3 on: April 23, 2017, 08:49:37 PM »
Derek,
Had a similar issue today.  Just got my boat in the water yesterday, and this morning it was gorgeous with 10 knot winds from the west (off shore) and 65F temp.  I was very tempted to go out, but the forecast called for the winds to shift to the north and become gusty.  Fortunately I did go out.  In one hour the temp dropped from 65F to 45F with winds gusting to over 25 knots!  That's Wisconsin!

What replacement blocks should I order for the 3 in the picture?
Rob



2015 Horizon Day Cat, Waters End

Offline Aldebaran_III

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Re: No name swivel blocks -beware.
« Reply #4 on: April 24, 2017, 01:11:21 PM »
For the two top ones I used the Harken swivel blocks #168 http://www.harken.com/search.aspx?s=168
For the bottom one I didn't want it to swivel, so I used the Harken #146 http://www.harken.com/search.aspx?s=146 which is from the same series of Big Bullet blocks.
The only problem I had with this one was that the holes in the two tangs were quite far from the end of the stainless strips. I had to take off the small strip shackle that comes on the block and replace it with a longer stainless "D" shackle with the same pin size. The slight increase in thickness of this shackle relative to the original meant that I also replaced the bolt through the tang with a slightly longer one just to make sure that the bolt fully threaded into the self locking nut.

I must say. it was nice not having to squint up at the mast to make sure this block had not flipped, like it used to do.

Cheers,
Derek