Help me understand this block and fitting

Moderator: GreenLake

Help me understand this block and fitting

Postby RobH912 » Thu Feb 27, 2020 10:58 am

If I were near my boat this winter I would just take a screwdriver, remove this block and fitting, and answer my own question...

This is one of two blocks for my traveler set up, one of the blocks has a crack in the sheave / chip out and was thinking that I should replace both blocks. They look very original / old.

Is anyone familiar with this type of fitting & block from an older DS? Is it one piece (the block integrated into fitting), or if I take the screws off will I be able to replace the block and reattach the fitting? Trying to maintain any of the original hardware where it makes sense to do so.

Thanks!
Attachments
traveler deck block IMG_1813.jpeg
traveler deck block IMG_1813.jpeg (57.74 KiB) Viewed 1150 times
Rob


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Re: Help me understand this block and fitting

Postby GreenLake » Thu Feb 27, 2020 7:35 pm

Rob, I have a different vintage set of stand-up blocks in those locations. However, I rarely use them as blocks. My traveler has a block tied to it at mid point. The two ends are led through the blocks and then tied together with a knot that also leaves a short loop. That loop is hooked over a hook below the deck, centering the traveler. The idea is that the traveler could be unhooked when it shouldn't be centered, but rarely remember to do that. Mostly, I rely on the vang to control leech tension, even upwind, so I don't get that much mileage out of being able to adjust the traveler.

Given that, in your position, I wouldn't bother with these blocks if they are only slightly marginal. Only if they start catching the traveler when you want it to adjust.

On your question, I would be comfortable with the assumption that these are inseparable from their base. I looked around a bit to see whether anyone sells anything compatible, but didn't find anything.

Most modern small stand-up blocks have a two-hole eye-strap as the base. You could also get some blocks that are raised and have a fixed orientation (for these traveler blocks you wouldn't really need much adjustability outside the plane (if any), so those might work. They tend to have two parallel L shaped feet, with four holes (but probably not matching the existing pattern). Garhauer has a 50mm block (a bit large) that has a circular base that would probably cover the existing holes.

You might want to check whether the blocks are through-bolted, or whether there's a glassed-in backing plate with threads tapped. (Some of the original fittings on the DS seem to have those).
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Re: Help me understand this block and fitting

Postby RobH912 » Thu Feb 27, 2020 9:43 pm

GreenLake wrote:On your question, I would be comfortable with the assumption that these are inseparable from their base. I looked around a bit to see whether anyone sells anything compatible, but didn't find anything..


GL - Thanks for the reply. Last fall I made a list of things to look at on the new boat before spring, took a lot of pictures, and made a number of measurements. I've been working through that list this winter, and my impression from last fall agrees with your assumption the the blocks and base are one piece.

I've attached some pictures of how the traveler is currently set up with these two blocks, plus a block (a Whale logo block) that is tied to the line that is the traveler, and then cleated under the tiller. I don't have a picture of my boat rigged, but the main sheet is tied into the becket on the aft block attached to the boom, then runs down to the traveler block (the whale logo block), back up to the block on the aft of the boom, then forward to another block down to block & cleat on the centerboard housing.

Also attached is a picture from a post on how the DS Lollypop was rigged. Found this on our site, saved the picture, but at the moment can't find it again to point to. My boat seems to be rigged the same.

All of the three blocks in the existing traveler setup are very small, not 30mm. I was going to replace the block that handles the main sheet tied to the traveler line with a Ronstan Series 40 Orbit Single Block with Becket.

Assuming that the existing blocks / base would be replaced I was thinking of either the Ronstan 30mm or the 40mm stand up. Something like these https://www.westmarine.com/buy/ronstan- ... cordNum=50

For the traveler line, I am looking at 6mm Bzzz line running through the two standup blocks and tied into the 40mm main sheet traveler block using an alpine butterfly loop knot. https://www.animatedknots.com/alpine-bu ... -loop-knot

WDYT?

Thanks!
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IMG_1860.jpeg
IMG_1860.jpeg (89.46 KiB) Viewed 1130 times
IMG_1776.jpeg
IMG_1776.jpeg (144.58 KiB) Viewed 1130 times
Lollypop_ds-rig-one.jpg
Lollypop_ds-rig-one.jpg (14.46 KiB) Viewed 1130 times
Rob


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Cape Cod
Eastham, MA
RobH912
 
Posts: 165
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Re: Help me understand this block and fitting

Postby GreenLake » Fri Feb 28, 2020 1:49 am

Instead of a knot to center (like the one I copied from Lollipop) you have a way to add incremental play. I would be curious to find out whether that gives you a definite advantage. It's for sure easier to set/release than my setup, but then I haven't found occasion to want to play with that level of control. So, looking to learn from your experience.

Small / cheap / light weight blocks are the way to go for the standup blocks. 20mm to 30mm, whatever you can get. Except perhaps the one that the main sheet runs through -- you will be glad for any reduction in mainsheet friction it when the wind is light. So 40mm seems OK. For the standup blocks, there's a slightly cheaper version, perhaps 25% less and looks functionally similar. Not much difference, but some people like to spend less. The traveler line can be a bit stiff. It doesn't move very much.

The butterfly knot is a good one to use. I tied a simple overhand knot at one point and after a few years could not open it again and the strap from the block was wider at the ends to fit the pin, so I couldn't get it out that way either. But then, there's really no need to take that apart before the end of its life cycle.

Looks like you are headed in a clear direction.
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Re: Help me understand this block and fitting

Postby RobH912 » Fri Feb 28, 2020 12:37 pm

GL - Thanks for the reply.

From the Lollypop picture, I couldn't see the knot to center. This traveler setup was how the boat came to me, so yes it will be interesting to see how it performs, but does look simple to use.

I'll look at other standup blocks, had just provided a link as an example of what I was thinking about, but I do think that having a swivel head block would be better than fixed.

Do you think I need a standup block? Maybe just a 30mm swivel block with an eye strap fitting?

I'll check the boat to see if the "existing blocks are through-bolted, or whether there's a glassed-in backing plate with threads tapped." That's a good thought.

Thanks!
Rob


DS1 #2444
Cape Cod
Eastham, MA
RobH912
 
Posts: 165
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Re: Help me understand this block and fitting

Postby GreenLake » Fri Feb 28, 2020 4:58 pm

Stand-up just adds the little spring so the block doesn't flap around. For this application it's in principle optional.

You might be able to cut apart the current blocks w/o damaging the ring held by the plate. If so, you might be able to attach a different block to the existing base. But it would require having access to the intended replacement as the dimensions of its strap would be crucial, and those aren't reliably determined without a specimen at hand. And doing the cutting might not be the easiest. Could work, though.

There's a knot there in the rigging for the Lollipop traveler, but I admit I know that from the written description.
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Re: Help me understand this block and fitting

Postby RobH912 » Fri Feb 28, 2020 8:00 pm

GreenLake wrote:You might be able to cut apart the current blocks w/o damaging the ring held by the plate. If so, you might be able to attach a different block to the existing base. But it would require having access to the intended replacement as the dimensions of its strap would be crucial, and those aren't reliably determined without a specimen at hand. And doing the cutting might not be the easiest. Could work, though.


GL - I also thought about cutting the block off of the ring then adding a new block to the existing fitting. Maybe cutting it off with a Dremel tool? Have you tried something like that?

Then replacing with a new block. Maybe using a soft shackle?

From a different post we talked about tying up some soft shackles. I ordered the wrong 4mm line, didn't realize that what I ordered was dyneema but line had a cover. When I stripped the cover off the core, it was just way too small (2mm?) to try to tie a shackle. I've ordered some non-covered 4mm line.

Thanks
Rob


DS1 #2444
Cape Cod
Eastham, MA
RobH912
 
Posts: 165
Joined: Thu Sep 20, 2018 9:33 pm

Re: Help me understand this block and fitting

Postby GreenLake » Fri Feb 28, 2020 11:39 pm

Don't own a Dremel, but you might be correct: this is probably not the job for a fullsize angle grinder. (Don't know if a hacksaw would be up to it).

Soft shackle: you are almost there. What you want is a block that doesn't have a shackle, but is instead tied with a lashing. The line for the lashing should be 2mm with cover. Something really thin, so you can pass multiple turns.

I'm using this technique for tying my spinnaker blocks to the stern cleats as in this photo.

2142

Now, you can do even better with a block that is designed to be tied through an eye in the hub of the block. Harken calls these "soft-attach" blocks and you can get a 29mm. Their picture shows a bit bigger line, but you should use what fits the ring after you cut off the block. All these modern lines are way stronger than needed, the extra just gives a reserve in case of chafing/UV exposure, so don't be afraid to go small diameter. The key is to fit multiple turns.

If you use a lashing, you can just leave the block "floppy" (i.e. not bother about stand-up)
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Re: Help me understand this block and fitting

Postby RobH912 » Sat Feb 29, 2020 10:45 am

GL - I like the idea of lashing a block to existing fitting.

These blocks also come with their own lashing line as well and are less expensive than conventional blocks I was thinking about.

https://www.ronstan.us/marine5/product. ... No=RF35101

Dremel tools are great for sanding, grinding, cutting small areas / items. Here is a link to a Youtube video showing a metal cutting example https://www.youtube.com/watch?v=y7Uugwya0_8&app=desktop

I'll wait until I get back to the boat in the spring so I can see what the set up is and then make a decision on what to do.

This thread has been very helpful.

Thanks!
Rob


DS1 #2444
Cape Cod
Eastham, MA
RobH912
 
Posts: 165
Joined: Thu Sep 20, 2018 9:33 pm

Re: Help me understand this block and fitting

Postby RobH912 » Sat Feb 29, 2020 10:51 am

one last piece of info for anyone looking at this thread, here are Ronstan's instructions on lashing their blocks

https://www.ronstan.com/marine/s20-orbi ... ctions.asp
Rob


DS1 #2444
Cape Cod
Eastham, MA
RobH912
 
Posts: 165
Joined: Thu Sep 20, 2018 9:33 pm

Re: Help me understand this block and fitting

Postby GreenLake » Sat Feb 29, 2020 3:59 pm

Thanks for posting those links. That's what makes these discussions such resource. After your upgrade, please post some pictures.
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