Traditional whipping?

[jalmberg]

I just made my first wooden block, and love how it came out -- except for the whipping.

https://lh4.googleusercontent.com/_KWIIP1jb40Q/TaoTke2I0gI/AAAAAAAADsQ/bgqh06FMsLY/s720/complete_block.jpg

The white, waxed synthetic thread (Nylon?) that you can buy at marine stores just doesn't look right. What did sailors use in the olden days?

-- John

[Canoeyawl]

Tarred marline

http://www.tarsmell.com/Images/marline6-3.jpg (http://www.tarsmell.com/marline.html)

[Peerie Maa]

I just made my first wooden block, and love how it came out -- except for the whipping.

https://lh4.googleusercontent.com/_KWIIP1jb40Q/TaoTke2I0gI/AAAAAAAADsQ/bgqh06FMsLY/s720/complete_block.jpg

The white, waxed synthetic thread (Nylon?) that you can buy at marine stores just doesn't look right. What did sailors use in the olden days?

-- John

Tarred marline. The strop would have been shorter so that one round lashing would have completed the block. the strop will have been wormed, parceled and served for protection as well.
This is nearly right
http://www.wrenhouse.com/images/one-of-a-kind/nautical-blocks/single-round/block-1.jpg

[jalmberg]

M'mmm. That looks nice. Now you've got me rethinking the varnish vs. oil finish, too ;-)

[BarnacleGrim]

What did sailors use in the olden days?
Same thing as sailors use today! Tarred marline is still used to whip pilot ladders. The pilots won't have it any other way, the synthetic stuff is too slippery.

Unfortunately for all the other whipping needs we use duct tape.

[Canoeyawl]

When I'm sailing I always carry a small roll of 3M "super 33" electricians tape in my pocket - Often mistaken for a can of "snoose" it's traditional now.

That and my butane backsplicer and I can throw a whipping on any line in about 30 seconds.

[dredbob]

While traditional natural fiber tarred marline is still available, two modern substitutes that are widely used now are waxed polyester sail twine and tarred nylon seine (or net) twine. I crew on a replica 16th century square rigger and the tarred nylon is what we use almost exclusively for seizings and whippings. It is available in a range of sizes from very small to quite stout, and the tarred coating gives it both protection and some needed stickiness.

The tarred twine is black, which goes well since a lot of our standing rigging is treated with black tar, or nowadays, black latex paint.

The waxed polyester is available in white and brown. White is good for hand stitching sails or canvas, the brown looks better for whippings and such.

The tarred nylon is available from many fisherman supply houses. Just do a google search for net twine or seine twine. There may be a local supplier in your area, especially if there is still any commercial fishing going on. The polyester can be had from Defender or other boating or sailmaker supply houses. Do yourself a favor, get a one pound roll, it'll cost a lot less that way and be pretty much a lifetime supply.


Bob

[Woxbox]

Word police here: What you have there would be a seizing, since you're binding two lines together. A whipping binds the end of a single line. And there are lashings, too, of course. (None to be delivered today.)

I can't tell for certain from the photo, but I have a hunch you applied that seizing without any tension in the line. To apply a seizing that will hold with certainty, you want to set the block up under significant tension so the grommet is stretched out to it's loaded length. If not, there's a risk that it will stretch in use and the block will pop out.

Two uprights at each end of the workbench and a 4/1 tackle or handy billy will do the trick. It's harder to snug it down like that, but the finished job is really solid.

[jalmberg]

Whoops, you are right about the word. You can tell I'm a newbie.

Also right about not applying tension. I used racking seizing, as described in the duckworks tutorial. I'm using Hempex, not hemp, so there is not much stretch in the line, but I'll try your idea when I re-do it.

After seeing Nick's example, I'm obviously not satisfied with the whole grommet part of the block. I'm going to make a shorter grommet, and I've ordered some tarred marline and bronze thimbles. I need to make a whole set for my Blue Moon yawl, so will get lots of practice making these. Should be an expert by the time I'm done ;-)

Thanks for all the tips, guys.

[Peerie Maa]

I used racking seizing, as described in the duckworks tutorial.


Did you put on a second layer like this:
http://freepages.genealogy.rootsweb.ancestry.com/~pbtyc/B_S_M/Images/124_Racking_Seizing_2.jpg

If so the only thing missing are the frapping turns, which tighten the whole thing up, like this.
http://freepages.genealogy.rootsweb.ancestry.com/~pbtyc/B_S_M/Images/124_Racking_Seizing_3.jpg
Without the second layer and frapping turns, you have applied a flat siezing, which is not really adequate for a permanent job.

[jalmberg]

Yes, I have the racking turns & second layer. No frapping turns, obviously. Actually, I was going to add them, but by then I already hated the way the seizing looked and stopped to ask my original question.

There are an amazing number of small skills needed for just this simple block.

[jalmberg]

Did you make that varnished block, Nick? I love the two different woods... wish I'd thought of that. Also, I realize now I could use thinner wood for the cheeks. The spacer needs to be thick (3/4"), because I'm running 1/2" line through it, but I could have used 1/2" oak for the cheeks.

Also, I probably could have cut more away from the corners, to make it a bit more oval, but probably that takes experience to figure out how much you can cut away while still retaining the strength. Rectangular is safer for now.

Live and learn...

[Peerie Maa]

Did you make that varnished block, Nick? I love the two different woods... wish I'd thought of that. Also, I realize now I could use thinner wood for the cheeks. The spacer needs to be thick (3/4"), because I'm running 1/2" line through it, but I could have used 1/2" oak for the cheeks.

Also, I probably could have cut more away from the corners, to make it a bit more oval, but probably that takes experience to figure out how much you can cut away while still retaining the strength. Rectangular is safer for now.

Live and learn...

No, not one of mine, I searched a suitable image on the web. I'm refurbishing iron bound blocks at the moment.
Any hard wood with a curly grain is ideal for blocks, elm is best.
The strength is in compression from the pin down to the strop at the bottom of the block. The cheeks act as fairleads to keep the rope on the sheave, so you can fair off the corners to your hearts content.
Peerie Maa's sheet blocks will give you some idea.
http://i408.photobucket.com/albums/pp164/peerie_maa/Idiot%20proof/finished004.jpg?t=1303058976

[jalmberg]

Another good reason to use tarred marline is you don't need so many wrap!

Well, I couldn't find any marline locally, and I need this block for tomorrow, so used a shorter grommet (still not short enough, but good enough for now), and tried seizing it under tension.

I didn't think it would be possible to put those racking turns on and draw the two parts together, but surprisingly, it wasn't that hard. I guess all those racking turns are like a screw, or a bunch of small pulleys. There's some kind of mechanical advantage going on there. The rope in the grommet got as hard as a rock.

Anyway, I think it looks a heck of a lot better, and it's certainly stronger than it was this morning. Good enough till I get the rest of the stuff I ordered.

https://lh4.googleusercontent.com/_KWIIP1jb40Q/TatRNlSCMtI/AAAAAAAADsw/6ug8t9DKSZ0/s720/block_stretched.jpg

It was too nice a day (finally!) to work indoors. Spring is coming!

[Peerie Maa]

Another good reason to use tarred marline is you don't need so many wrap!

Well, I couldn't find any marline locally, and I need this block for tomorrow, so used a shorter grommet (still not short enough, but good enough for now), and tried seizing it under tension.

I didn't think it would be possible to put those racking turns on and draw the two parts together, but surprisingly, it wasn't that hard. I guess all those racking turns are like a screw, or a bunch of small pulleys. There's some kind of mechanical advantage going on there. The rope in the grommet got as hard as a rock.

Anyway, I think it looks a heck of a lot better, and it's certainly stronger than it was this morning. Good enough till I get the rest of the stuff I ordered.

https://lh4.googleusercontent.com/_KWIIP1jb40Q/TatRNlSCMtI/AAAAAAAADsw/6ug8t9DKSZ0/s720/block_stretched.jpg

It was too nice a day (finally!) to work indoors. Spring is coming!

Much better. A bit of fine tuning, - you need to relieve the spacer at the arse of the block so that the rope does not chafe as it comes off the pulley. The two scallops should mimic the diameter of the pulley.
For the next shell that you build the grain on the cheeks usually runs up and down not across, less chance of the pin crushing the wood and coming loose .

Nice camera and tripod.

[jalmberg]

Ah... good eye. I did make a fair size 'scallop' (is that really the word?) but now that you draw my attention to it, I can see it's not deep enough by half. Will have to fix that (good thing I didn't varnish it!)

The wood is maple, and the grain is running across the face of the cheek... so that the 3/8" pin is resting on the grain, so to speak. Although from the end grain, it's hard to tell.

That's correct, isn't it? Wouldn't the wood be more likely to split of the pin was pushing in the same direction as the grain?

Anyway, with 3/4" cheeks, it should be strong enough, I hope.

[Peerie Maa]

That's correct, isn't it? Wouldn't the wood be more likely to split of the pin was pushing in the same direction as the grain?



That is why you want a gnarly grained wood. Wood end grain is stronger in compression than the cross grain. The pin diameter will be designed to give enough bearing area to avoid splitting the cheeks.

[Sailor]

I love block threads. Mainly because I have yet to build my blocks.

[Woxbox]

The rope in the grommet got as hard as a rock.

That's a good sign that you have it right. Great progress.

Here's a seine twine source (http://www.memphisnet.net/category/twine_tarredseine). I haven't purchased from this outfit, so it's not a recommendation, just a potential source. Others on the forum have suggested suppliers for this same stuff, a search may find it. I'm not sure which weight to recommend for your blocks. In some shots, it looks smaller, and in others hefty. But if you have several spools of various weights of this twine on your boat, you'll find it endlessly useful. On the Kalmar Nyckel, it gets used everywhere -- from holding the rig together to lashing things down when it gets rough to hat and glasses lanyards.

[jalmberg]

That is why you want a gnarly grained wood. Wood end grain is stronger in compression than the cross grain. The pin diameter will be designed to give enough bearing area to avoid splitting the cheeks.

Huh. Now that is counter intuitive. I wouldn't have guessed that.

That makes it difficult to use something like this:

https://lh6.googleusercontent.com/_KWIIP1jb40Q/TaoTkW5aHHI/AAAAAAAADsY/yebZWrVIoY4/s720/10_blanks.jpg

Very handy for making a bunch of blanks all at once.

Actually, the grain on this maple is all over the place. I can't quite figure out which way it's running.

[jalmberg]

That's a good sign that you have it right. Great progress.

Here's a seine twine source (http://www.memphisnet.net/category/twine_tarredseine). I haven't purchased from this outfit, so it's not a recommendation, just a potential source. Others on the forum have suggested suppliers for this same stuff, a search may find it. I'm not sure which weight to recommend for your blocks. In some shots, it looks smaller, and in others hefty. But if you have several spools of various weights of this twine on your boat, you'll find it endlessly useful. On the Kalmar Nyckel, it gets used everywhere -- from holding the rig together to lashing things down when it gets rough to hat and glasses lanyards.

You know, I just looked through the whole Rigger's Apprentice again, and did not find anything on doing seizing under tension. It's not in the Duckworks tutorial, either. So thanks for the tip.

Not only did it make it stronger, but it was actually easier to do the seizing when all the bits were held rigidly in the right place. I wrapped the seizing twine on a dowel -- a primitive shuttle, I guess. You can see it lying on the ground in this photo. That made it easier to make all the turns, and to haul the turns tight. I switched to a smaller dowel when the spacing got tight.

https://lh4.googleusercontent.com/_KWIIP1jb40Q/TatWk-lJsOI/AAAAAAAADs4/eHQbfJzJxEU/s720/DSCN4456.jpg

Good stuff!

[Thad Van Gilder]

doesn't the teardrop shaped thimble look odd to anyone else? I use round ones myself...

-Thad

PS, if you ever make it down to Cape May, New Jersey, There is a commercial fishing supply house right at the bottom of the parkway that carries seine twine.

[jalmberg]

doesn't the teardrop shaped thimble look odd to anyone else? I use round ones myself...

-Thad

PS, if you ever make it down to Cape May, New Jersey, There is a commercial fishing supply house right at the bottom of the parkway that carries seine twine.

I've got round ones on order, but I've been playing around with what I had on hand.

I sailed through Cape May last fall on my way up the ICW... Delaware Bay and the NJ ICW -- toughest part of the whole trip.

[Peerie Maa]

Huh. Now that is counter intuitive. I wouldn't have guessed that.

That makes it difficult to use something like this:

https://lh6.googleusercontent.com/_KWIIP1jb40Q/TaoTkW5aHHI/AAAAAAAADsY/yebZWrVIoY4/s720/10_blanks.jpg

Very handy for making a bunch of blanks all at once.

Actually, the grain on this maple is all over the place. I can't quite figure out which way it's running.

If you do need to make any more, lay them out like this:
http://i408.photobucket.com/albums/pp164/peerie_maa/blockblank.jpg
Crappy sketch, but I hope that it is clear enough.

[jalmberg]

Pretty clear, Nick. Thanks.

Here's my blog post if anyone is interested in the gory details:

http://www.unlikelyboatbuilder.com/2011/04/department-of-duh.html

I was hoping to get the sails back on the Blue Moon today, but the paint on my spars still isn't dry after 4 days! But that's another problem, that I don't want to get into until the paint company (small, family owned) returns my phone calls. Obviously, I've done something wrong, but I can't figure out what...

Ah well. Boats!

[blindbrook]

John,
Does this mean the new tender project is on hold? We just passed the halfway mark on our planking this weekend.

[jalmberg]

John,
Does this mean the new tender project is on hold? We just passed the halfway mark on our planking this weekend.

Not on hold, really, but I've had to switch gears to get the BM back in sailing shape. No way I was going to finish Vintage in time for the Wooden Boat Show, but I promised Pat Atkin to bring something, so I'm going to give Cabin Boy a well-deserved re-fit and bring him. I bet he'll be the only boat at the "I Built It Myself" show with 2000 miles on its bottom :-)

If there were only 48 hours in a day...

-- John

[Covite]

...Not only did it make it stronger, but it was actually easier to do the seizing when all the bits were held rigidly in the right place. I wrapped the seizing twine on a dowel -- a primitive shuttle, I guess. You can see it lying on the ground in this photo. That made it easier to make all the turns, and to haul the turns tight. I switched to a smaller dowel when the spacing got tight. ...

Also be sure to check out Clyderigged's excellent videos on the Heaver hitch and marlingspike hitch as mentioned in a previous thread:

http://forum.woodenboat.com/showthread.php?73171-Marlingspike-amp-Heaver-hitch-videos&

I use the Heaver hitch to get seizings very tight, as they must be to realize their full strength. It makes for a really proper job!

[jalmberg]

This version uses a smaller grommet (still a bit big, perhaps), with tarred nylon (very strong) for racking turns, and tarred hemp for the other turns (for looks.) This one's a keeper, I think.

https://lh3.googleusercontent.com/_KWIIP1jb40Q/TbixSm4YFYI/AAAAAAAADtU/IUYDexEnKeU/s640/DSCN4469.jpg

[Woxbox]

That looks really nice, and it should hold up very well. My only comment would be that the hemp doesn't need to be that heavy to do the job. It would be easier to work and look neater too with a smaller diameter line. But don't toss that one out!

Okay, I keep looking at it and have one other comment. There is a particular way to finish off those racking turns, and I don't see it, unless it's on the other side of the block. Here's a video (http://www.itstactical.com/skillcom/knots/knot-of-the-week-common-rope-seizing/?replytocom=22952) that isn't to be followed for most of what the guy says, but he does finish off the frapping turns nicely. But don't do has he says and leave the last two turns loose so you can thread the end with your fingers. Pull those final turns tight -- but over two loops of light line laid down in the direction you'll want to pull the end through. So you lay the turns tight, pass the end of the line in one loop first, pull it through. Then put it through the second loop, and pull it back through and out the middle, which will finish the knot as it's shown in that video. But yours will be much snugger that his. If you want to for security, you can put a half-hitch in the bitter end of the line before trimming off the excess. That creates a "button" that prevents the end from slipping out.

[jalmberg]

Thanks for the great tips. The hemp was a bit too thick, which is why I used the nylon for the racking turns. But the hemp is 2-ply, so next time I'll just use one of the plys.

And you put your finger on my one big question, which is how to start and finish the turns. I've tried several methods, but none of them seemed quite right. The method in the video look much better. I'll try it on the next one.

While I was waiting for the marline to arrive, I cut out the next block. I took a lot more off the block, made it more oval shaped. Much lighter and better looking.

But this one is good enough, I think. Just need to make the 'scallops' deeper so the line doesn't rub on it. H'mmm... sure wish I had remembered that BEFORE putting the seizing on. I might end up re-doing this, after all ;-(

These are really fun to make, and bring a whole lot of skills together.

[Todd Bradshaw]

If you set enough round thimbles, it's worth making two-part fids like this to fit them tightly into the line. The design can vary, but the inner shaft should just fit inside the thimble and the maximum diameter of the pointed part should match the outside diameter of the thimble. To set the thimble, you make your rope loop snug and without the thimble. Then you assemble the fid with the thimble inserted, up-end it, stick the tip through the rope loop and drive it through with a mallet, using a backing board with a hole in it. Once you get far enough for the rope loop to drop into position around the thimble, you take the fid apart and have a nice, tightly-fitted thimble.

http://webpages.charter.net/tbradshaw/fids.jpg

[jalmberg]

Huh... So you make the loop, then insert the thimble? Interesting!

As I said, lots of skills & techniques for these blocks. Must have been an interesting job, when there was a market for beautiful blocks.

Did you make those fids? Are they turned? Is that some sort of metal band around the female part of the fid? Reinforcement?

Really nice.

[Todd Bradshaw]

Yes, I turned them to match the sizes of thimbles that I use for sail cringles. The rule of thumb for thimbles is that they should be held tightly enough that they're difficult to turn, so you start with a slightly undersized loop and stretch it as you insert the thimble. The traditional way to do this is by jamming a regular fid into the loop to stretch it, then pulling the fid out and quickly trying to tap the thimble in before the loop shrinks back up. In practice, I found that method to be rather haphazard and often frustrating. With the two-piece fid, once the loop is stretched it pops over the thimble automatically and you're done. The little band around the fid is just a lashing of a bunch of turns taken with polyester thread to help prevent splitting (something I actually borrowed from bagpipe reeds, of all places).

In my line of work, we use the thimbles a little bit differently. They lay up against the sail's roped edge on one side and are surrounded on the outside by a 3-strand loop that's actually woven from a single strand passing back and forth between a couple of reinforced anchor holes in the sail. It's the same basic deal though. We want them tight enough that there is no way they'll fall out in use and the fids help insure that.

http://webpages.charter.net/tbradshaw/cringles.jpg

[jalmberg]

Next iteration: oval shaped with tarred nylon seizing (thanks, Dave!)

Cutting off the corners to make the block oval-shaped makes it quite a bit lighter, and tucks the bottom of the block out of the way of the line run through the block.

Getting the grommet size right, and the seizing right has turned out to be the real challenge of this project. I've found it quite difficult to get the grommet the right size within a half-inch or so. This one comes close, but I threw away 2 of them... one a smidge too small and one too big!

Finally broke down and bought Ashley's Book of Knots. I always thought it was overkill, but now I'm wishing I'd bought it when I started with this whole wooden boat thing! Unbelievable resource.

https://lh3.googleusercontent.com/_KWIIP1jb40Q/Tbt_S-tEFkI/AAAAAAAADto/SZ5gTwcABVc/s640/DSCN4473.jpg

[captsct]

Question on thickness needed for the cheeks: I'm thinking of making the blocks for my boat, which is still under construction. I'll be using 3/8" and 1/2" lines through them. I've found some measurements for commercial made blocks of the appropriate sizes, but not the thickness of the cheeks. How thin can I go and make sure they'll be strong enough? 1/2", 3/8"? and what about the center cheek in a double or triple, can it be significantly thinner, say 1/4", or need to be the same as the outer cheeks?

I had made some previously for a decorative piece from the duckworks plans and used UHMDW plastic for the sheaves. It cut and grooved nicely, and with 1/4" line the blocks work great. Would this material be strong enough not to distort under working loads, or will I need to go with metal or wooden sheaves?

This thread had been most informative, thank you.
Scott

[Peerie Maa]

Question on thickness needed for the cheeks: I'm thinking of making the blocks for my boat, which is still under construction. I'll be using 3/8" and 1/2" lines through them. I've found some measurements for commercial made blocks of the appropriate sizes, but not the thickness of the cheeks. How thin can I go and make sure they'll be strong enough? 1/2", 3/8"? and what about the center cheek in a double or triple, can it be significantly thinner, say 1/4", or need to be the same as the outer cheeks?
Scott

Hervey Garrett Smith quotes a tad under half an inch cheeks for 3/8 rope with larger sizes in proportion. The middle cheek will be thinner, your 1/4 will be OK.

[Sailor]

I think the "ovaling" has done wonders for the look of the block. Have you thought of "ovaling" in the other direction as well? Make it more egg shaped? That style of block is my absolute favorite and I know I will use them on my boats. Nice work. I'll be coming back to this thread from time to time when I build my blocks.

[jalmberg]

Question on thickness needed for the cheeks: I'm thinking of making the blocks for my boat, which is still under construction. I'll be using 3/8" and 1/2" lines through them. I've found some measurements for commercial made blocks of the appropriate sizes, but not the thickness of the cheeks. How thin can I go and make sure they'll be strong enough? 1/2", 3/8"? and what about the center cheek in a double or triple, can it be significantly thinner, say 1/4", or need to be the same as the outer cheeks?

I had made some previously for a decorative piece from the duckworks plans and used UHMDW plastic for the sheaves. It cut and grooved nicely, and with 1/4" line the blocks work great. Would this material be strong enough not to distort under working loads, or will I need to go with metal or wooden sheaves?

This thread had been most informative, thank you.
Scott

Mine cheeks a bit less than 3/4", and I think they are probably too thick. I've been thinking of taking 1/4" off the next set.

I'm also thinking of using different color woods for the cheeks and spacers. I think that would look really nice.

I wouldn't worry too much about the sheaves... at this point, I can make a new sheave in about 15 minutes, and install it in about the same amount of time, so if you make one in one material and it doesn't work out, you can just make a new one.

The wooden sheaves work beautifully when oiled, so I have a small oil can on the boat filled with linseed oil. If/when they start to squeek, I'll just squirt some oil in them and they should be good to go.

[jalmberg]

I think the "ovaling" has done wonders for the look of the block. Have you thought of "ovaling" in the other direction as well? Make it more egg shaped? That style of block is my absolute favorite and I know I will use them on my boats. Nice work. I'll be coming back to this thread from time to time when I build my blocks.

Actually, no, I haven't... That would be a way of reducing the cheek size. Do you have a picture of one?

[jalmberg]

Hervey Garrett Smith quotes a tad under half an inch cheeks for 3/8 rope with larger sizes in proportion. The middle cheek will be thinner, your 1/4 will be OK.

H'mmm. So maybe 3/4" is about right for 1/2" rope. I swapped out my first metal/plastic block for the wooden one above, and it looks right for the size rope, so maybe it is.

[jalmberg]

Do the grommets for sheet blocks -- i.e., blocks that will spend their lives swinging from a boom -- really need serving? They're not going to be chafing on anything, so I can't see much use for serving.

Actually, its hard to imagine a scenario where the grommet would be chafed. Maybe one at the top of a mast?

[Peerie Maa]

Do the grommets for sheet blocks -- i.e., blocks that will spend their lives swinging from a boom -- really need serving? They're not going to be chafing on anything, so I can't see much use for serving.

Actually, its hard to imagine a scenario where the grommet would be chafed. Maybe one at the top of a mast?

Service also protects from rot, previously from fungal rot, now a days from UV degradation.

[jalmberg]

Service also protects from rot, previously from fungal rot, now a days from UV degradation.

Ah. That makes sense. Thanks.

[Thad Van Gilder]

I have turned quite a few sheaves from lignum vitae with great results, and no oiling needed!!!!

[Dave Lesser]

John,

Here are some photos that I have collected of various blocks . This is not my work. Several of them were made by Bob Albers, who is currently building the Peterson schooner "Susan".

http://farm6.static.flickr.com/5229/5680068694_e369dc71fa.jpg

http://farm6.static.flickr.com/5222/5679508515_346a343aef.jpg

http://farm6.static.flickr.com/5067/5680068392_71610d3823.jpg

http://farm6.static.flickr.com/5184/5679508333_57570088e8.jpg

[jalmberg]

I have turned quite a few sheaves from lignum vitae with great results, and no oiling needed!!!!

I looked for some, but apparently its now illegal to import it into the US. Consequently, it's $$$. Do you have a source for the real stuff?

[Dave Lesser]

A few more:

http://farm6.static.flickr.com/5024/5680067980_67621754ec.jpg

http://farm6.static.flickr.com/5106/5679507953_3d3b2e2cd2.jpg

http://farm6.static.flickr.com/5110/5679507903_b045e4dd3a.jpg

[jalmberg]

I see what you mean by oval. It looks like they have a bit more meat above and below the sheaves, to compensate for the extra wood removed.

They do look pretty nice!

[Dave Lesser]

Zephyrwerks in Port Townsend makes Delrin sheaves with oilite bearings. Not cheap.

http://farm6.static.flickr.com/5025/5680152538_a3f79121cf.jpg

[Thad Van Gilder]

yes L and M in northern NJ is the primary importer.

www.lignum-vitae.com

I bought most of what I have right now from another importer, diamond tropical hardwoods in bucks county, pa

http://www.diamondtropicalhardwoods.com/

Kevin Yardley owns diamond tropical and he is very, very good to deal with!!!!!

-Thad

[jalmberg]

Zephyrwerks in Port Townsend makes Delrin sheaves with oilite bearings. Not cheap.


The cheapest sheaves are wood, if you don't count your time. Out-right cheapest are plastic with no bearings that are readily available, even from West Marine. I'm going to stick with the wood ones to see how they work over a summer. If they need too much care (not sure what that means, yet) then I might try plastic ones.

I don't consider an occasional squirt of oil too much care, so we'll just have to see how it goes.

[Don Z.]

Oval blocks:
http://www.marinestore.co.uk/Merchant2/graphics/00000001/da0610.jpg
http://www.marinestore.co.uk/Merchant2/graphics/00000001/da0617.jpg

[jalmberg]

yes L and M in northern NJ is the primary importer.

www.lignum-vitae.com

I bought most of what I have right now from another importer, diamond tropical hardwoods in bucks county, pa

http://www.diamondtropicalhardwoods.com/

Kevin Yardley owns diamond tropical and he is very, very good to deal with!!!!!

-Thad

Just sent Kevin an email. Thanks!

[Sailor]

http://farm6.static.flickr.com/5229/5680068694_e369dc71fa.jpg
http://farm6.static.flickr.com/5184/5679508333_57570088e8.jpg

These are what I meant. They are a beautiful example of the blockmaker's art. I particularly love the proportions and aesthetics of the second one.

[jalmberg]

These are what I meant. They are a beautiful example of the blockmaker's art. I particularly love the proportions and aesthetics of the second one.

De-lish... the bronze sheaves look great, too.

Making them oval in one dimension makes for a lot more work in shaping. Making them oval in two dimensions...

I'll have to give it a try on the next iteration.

[jalmberg]

http://farm6.static.flickr.com/5184/5679508333_57570088e8.jpg

These are what I meant. They are a beautiful example of the blockmaker's art. I particularly love the proportions and aesthetics of the second one.

Got any idea what kind of wood that is?

[Woxbox]

Blocks that run up and down in use can get hung up on stuff, the main reason to make them oval. Here's me amid a tangle of Kalmar Nyckel blocks. It pays to make sure your blocks will move when you need them to. Our blocks are all cut from a single piece of wood, rather than made up of three slices. They're almost all Courbaril, or South American locust. The pins are also wood on all but the biggest, but the sheaves were cut and turned from a composite material -- forget the name.

http://i45.photobucket.com/albums/f92/Woxbox/Daveonsprittop.jpg

[J. Dillon]

I would say these are the most beautiful blocks I've seen posted on this Forum.:d


JD

[Sharpie21]

This thread is fascinating. These wood, rope and bronze objects are a brilliant expression of the craft and attention to detail that goes into the building of a traditional wood boat. They seem like intricate functional gems suspended by a necklace of hemp line.

I know now that my daysailer Lady Grace won't be finished until she is adorned with a full complement of these gems.

A few practical questions about making these. It seems that the size of the finished grommet is key to making a success of it. Especially difficult to calculate when the stretch that must occur when they are tensioned prior to seizing. Any tips on how to size the grommets, other than trial and error?

Also, on the blocks that have the marlin wrapped around the grommet (prior to placing the thimble), is that done to secure the splice?

It seems to me that it would be best to place the splice at the grommet.

[jalmberg]

A few practical questions about making these. It seems that the size of the finished grommet is key to making a success of it. Especially difficult to calculate when the stretch that must occur when they are tensioned prior to seizing. Any tips on how to size the grommets, other than trial and error?

Also, on the blocks that have the marlin wrapped around the grommet (prior to placing the thimble), is that done to secure the splice?

It seems to me that it would be best to place the splice at the grommet.

First, grommets aren't spliced, really. You use one strand of a three strand rope that is 3 times the size of the splice, plus one foot extra.

The single strand is re-layed around itself three times, so you end up again with a three strand rope, but in the form of a continuous circle. You have two 6" ends left over that get tucked into the other strands to finish off the grommet.

You can get close to the right size just by wrapping a rope around the block and thimble, but then I had to use trial and error to find the exact size. Too small, and you can't bring the two strands together with seizing. Too big, and it just looks goofy.

However, at this point, I've probably made 2 dozen grommets, so I can make a new one in about 15 minutes. You need to practice to get them smooth, anyway.

The grommets are as strong as the rope you make them out of (I used Hempex) and don't need seizing.

Of course, as soon as you decide to service the grommets, the size changes, so you have to go through the whole trial and error process, again, but wrapping service is pretty time-consuming, so...

I'm still debating the pros and cons of servicing the grommet. I get the UV argument, but I think it might be easier to just replace the grommet every few years. If I did service them, I'd probably just do the 'top' near the grommet, that's most exposed to the sun, as you can see in several examples.

Anyway, I'm not going to service them until I've finalized my design. It's convenient for experimenting to be able to tear down a finished block and replace something fairly quickly. (A razor blade makes short work of the seizing.)

Lignum Vitae, by the way, is $70/board foot, so I'm thinking twice about that idea... An oil can full of linseed oil will set me back $5 and well-oiled wooden sheaves work really smoothly.

[jalmberg]

Blocks that run up and down in use can get hung up on stuff, the main reason to make them oval. Here's me amid a tangle of Kalmar Nyckel blocks. It pays to make sure your blocks will move when you need them to. Our blocks are all cut from a single piece of wood, rather than made up of three slices. They're almost all Courbaril, or South American locust. The pins are also wood on all but the biggest, but the sheaves were cut and turned from a composite material -- forget the name.


Cool picture. What boat is that?

Wooden pins, eh? That's a new twist, but I can see how an oak dowel, for instance, would be strong enough, thought perhaps not as slippery as a bronze pin.

Fascinating...

[chainyank]

I love block threads. Mainly because I have yet to build my blocks.

I second that!

[chainyank]

A thought about the grommets.... The one you are using on this test block seems to me to be too big, making for a very long seizing. Whether correct or not, the seizing/grommet ratio on the these blocks seems better. The forums thoughts?....
http://farm6.static.flickr.com/5184/5679508333_57570088e8.jpg

[Sharpie21]

A thought about the grommets.... The one you are using on this test block seems to me to be too big, making for a very long seizing. Whether correct or not, the seizing/grommet ratio on the these blocks seems better. The forums thoughts?....
http://farm6.static.flickr.com/5184/5679508333_57570088e8.jpg

I'll second that aesthetically....wondering, though, how many wraps does it take to keep the whole thing together under load?

[Woxbox]

Cool picture. What boat is that?

That's the sprit top of the Kalmar Nyckel. The idea was to be as true to the circa 1625 original as practical. So the blocks were done as they were then with wood pins. I've not known of a single one to fail after 13 seasons of regular sailing. But the sheaves are synthetic. I wasn't around the organization when the ship was built, and I don't know what all the considerations were. But there is a higher risk of failure with wood, and if the sheave twists or warps, it will jam up pretty good. I don't know how many blocks are on the ship, but I've come to believe that they're every bit as good as the modern alternatives. Consider that even if a shell did shatter, the grommet would catch the line so nothing would fall to the deck. Here's the full picture:

http://www.google.com/url?source=imgres&ct=img&q=http://www.wunderground.com/data/wximagenew/s/seafrog/336.jpg&sa=X&ei=H57ATbnKAZDrgQfZhIjRBQ&ved=0CAQQ8wc&usg=AFQjCNFC2Brah3n43c7JRAQlkZDS_n_m7Q

[jalmberg]

A thought about the grommets.... The one you are using on this test block seems to me to be too big, making for a very long seizing. Whether correct or not, the seizing/grommet ratio on the these blocks seems better. The forums thoughts?....


https://lh3.googleusercontent.com/_KWIIP1jb40Q/TcFcncDMncI/AAAAAAAADuE/F_3ukP0Ar_s/s640/DSCN4474.jpg

http://farm6.static.flickr.com/5184/5679508333_57570088e8.jpg

Aesthetics are only part of the question... It's my understanding that seizing should always be longer than it is wide -- i.e., about the same as the combined diameter of the ropes. So with two parts of 3/8" rope, the seizing should be at least 3/4" long... about what I've got on mine, now. I am not sure the seizing, and thus the grommet, shouldn't be a bit longer. I wouldn't want to go any shorter, even if it did look better.

The seizing on the oval/oval blocks looks great, but is only as long as one thickness of rope. Note that the builder was unable to draw the two parts together and has many frapping turns to cover the distance.

I'm not sure if this is good or bad, but it is definitely unconventional. Pictures of rope-stropped blocks in "Ashly's Book of Knots" all show long seizings and just a few frapping turns. Perhaps this is just a different technique that is just as good? I think there are probably many valid ways to skin this cat.

As I said, the grommet/seizing is the most complicated part of building these blocks!

[jalmberg]

H'mmm... an update on the above...

Just found this in Ashley, in the section on rope-stropped blocks: "There should be four to seven lower turns in an eye seizing, and one less riding turn."

So maybe I've been overestimating the amount of seizing required. On the other hand, all Ashley's drawings show a seizing that is longer than it is wide. Maybe because he is using fairly heavy tarred hemp, that's much thicker than tarred nylon.

Who knows?!?!? I need to close these books and get to work :-)

[jalmberg]

That's the sprit top of the Kalmar Nyckel. ... Here's the full picture:

http://www.google.com/url?source=imgres&ct=img&q=http://www.wunderground.com/data/wximagenew/s/seafrog/336.jpg&sa=X&ei=H57ATbnKAZDrgQfZhIjRBQ&ved=0CAQQ8wc&usg=AFQjCNFC2Brah3n43c7JRAQlkZDS_n_m7Q

All I can say is, wow.

Do you happen to know the best way to attach a block to a pad eye so it can swivel? I am thinking of my main sheet block, which needs to be attached to a heavy pad eye in the cockpit. If I just shackle the eye block to the pad eye, it doesn't swivel enough. I have a swivel shackle which does the job, but it doesn't look very traditional.

http://a248.e.akamai.net/f/248/21700/1d/content.westmarine.com/images/catalog/full/17581_f.jpg

I'm thinking using a tail block, instead of an eye block. Then the block could twist on the tail. Any other options?

[Thad Van Gilder]

What traditional design are you building that needs a swivel on the main sheet block?

BTW yes l.v. lists at $70 a b.f., but you can very often find it much, much cheaper!!!!!

I see 4/4 L.V. on ebay from time to time at as low as $20 a B.F.

-Thad

[jalmberg]

What traditional design are you building that needs a swivel on the main sheet block?


My 23' Blue Moon Yawl. Sometimes I sit on the right side of the cockpit, and sometimes on the left. I like the block to swivel so there's a fair lead to where ever the boom happens to be (usually on the opposite side of the boat, but not always.)

These eye blocks have no twist in them, at all, if the grommet is set up tight enough. I guess I could get away with one of those shackles with a 90 degree turn in them, so the block was oriented correctly, but it wouldn't always be a fair lead.

[Woxbox]

Do you happen to know the best way to attach a block to a pad eye so it can swivel?

Interesting question. I can't bring to mind a single block on the Kalmar Nyckel with a metal swivel of any kind. In every case, if a block needs to orient itself in more than one direction, it's suspended or held up on a length of line to allow this. You can see this in the photo of the sprit top above. There are blocks hung from the heavy black lines at the top of the photo, the upper one being the foretop stay, and the lower the forestay. Those blocks could be made up hard against the stays, but they are given a foot or two of scope so that they can orient themselves correctly.

So the question is, how were the mainsheets of fore and aft rigged boats handled in the period? The closest on the ship is the mizzen, where the sheet runs through a block on a ring bolt, but doesn't need to twist any more than that allows. Maybe a ring between the block and padeye is enough? A nicely woven pad underneath would protect the deck and add an elegant touch.

[Sharpie21]

Jalmberg, you are right that they are not spliced, but with the overlap, they look spliced. I had one in my hand as I wrote that comment, but I made it six months ago, and honestly couldn't remember the exact process.

Anyway, I can see now that the frapping turns can be used to make up for a grommet that is made a tad too short. And I do recall the advice that the seizings be at least equal to the width of the two diameters combined, but that advice was for line that might slide by it's mate, as in a thimble at the end of a line. Thus the friction of line-on-line is what keeps it from slipping.

It seems to me that the forces on these blocks are quite different, in that when they are under load the forces at play would tend to separate the lines. Is that clear?

Looking at the blocks shown above, the lines don't touch, so no friction is at work. Instead, the seizings, in tension, are bearing all the load. And in the beautifully made blocks shown, they seem to be a weak link in the system.

So my question is, as I asked it in an earlier post, how can we determine how many wraps of the light seizing line it takes to 'bear the load.'

(Maybe I am over analyzing this.http://forum.woodenboat.com/images/icons/icon5.png)

[jalmberg]

I don't think you are. If you imagine stressing the block until it breaks, what's going to give first?

Mind you, I don't expect to have a 2000 lb load on my main sheet! Unless some power boat clips me going down wind Y:o

[jalmberg]

Interesting question. I can't bring to mind a single block on the Kalmar Nyckel with a metal swivel of any kind. In every case, if a block needs to orient itself in more than one direction, it's suspended or held up on a length of line to allow this. You can see this in the photo of the sprit top above. There are blocks hung from the heavy black lines at the top of the photo, the upper one being the foretop stay, and the lower the forestay. Those blocks could be made up hard against the stays, but they are given a foot or two of scope so that they can orient themselves correctly.

So the question is, how were the mainsheets of fore and aft rigged boats handled in the period? The closest on the ship is the mizzen, where the sheet runs through a block on a ring bolt, but doesn't need to twist any more than that allows. Maybe a ring between the block and padeye is enough? A nicely woven pad underneath would protect the deck and add an elegant touch.

Been looking through Ashley for an answer. I've got a nice old bronze clip with an eye in it that I can work into the grommet. That would give me the 90 degree turn I need, and maybe enough play for tacking. Plus I can unhook the block to clear the deck and get the mainsheet away from the companionway door, which would be nice, sometimes.

I've already picked out the pattern for the 'thump mat' :-)

[Woxbox]

So my question is, as I asked it in an earlier post, how can we determine how many wraps of the light seizing line it takes to 'bear the load.'

I don't have a number, but as an example, the lightest seine twine that I see used is #9. It has a tensile strength of 81 pounds. If you do a round seizing of, say, 11 turns in two layers, you have 22 turns, or 44 strands holding the two parts together. 44 times 81 pounds is 3,564 pounds of holding power. And that's with the light stuff. Go to, say, #24, and now you're good for 286 pounds per strand, or a total of 12,584 pounds of grip. This stuff is way stronger than it looks, so yep, you are over analyzing this. As I mentioned before, this is all we have to hold in place 8 miles of line on the Kalmar Nyckel, and it just doesn't give up.

[Sharpie21]

Thanks for the data Woxbox, that's just what I needed to clarify this in my foggy mind... That and the fact that the seizings are doubled.

Where does one get data on the tensile strength of these lines (twines)?

Still thinking I just gotta have some of these gems on my Lady Grace, when I can find the time to make them.

[jalmberg]

I don't have a number, but as an example, the lightest seine twine that I see used is #9. It has a tensile strength of 81 pounds. If you do a round seizing of, say, 11 turns in two layers, you have 22 turns, or 44 strands holding the two parts together. 44 times 81 pounds is 3,564 pounds of holding power. And that's with the light stuff. Go to, say, #24, and now you're good for 286 pounds per strand, or a total of 12,584 pounds of grip. This stuff is way stronger than it looks, so yep, you are over analyzing this. As I mentioned before, this is all we have to hold in place 8 miles of line on the Kalmar Nyckel, and it just doesn't give up.

That puts things in perspective. I'm going to stop worrying about seizing, as of right now. Strong and beautiful. What more could you ask for?

[Vince Brennan]

Super recommendations and tips here!

Excellent group of blockheads!

[captsct]

I just got back from the local Woodcraft store. They have 4 pieces of lignum vitae for $17 and change per board feet. each about 4/4 x 4" x 30" S4S, and lots of pen blanks. I was kicking myself all the way out the door for not having the money to get them. With luck they'll still be there come payday. I need to carefully calculate how many of them I'll actually need for my sheaves. Oh shoot, I guess y'all get there and buy them up by then.

[Peerie Maa]

Will the pen blanks do for axle pins?

[Dave Lesser]

Do you know what Woodcraft is selling as Lignum Vitae?

From the lignum-vitae.com website:



It has come to our attention that there are some folks selling Argentine Lignum Vitae that has not been proven as a bearing material. Would you trust a ship in the middle of the ocean to a product that is unproven? Or would you risk the expense of a shut down of a hydro plant based on an unproven product? The key to knowing if you are getting the real Lignum Vitae is does the company have a CITES certificate. If not they do not have the real material. Period! We have the largest single source of bearing grade material in log and block form. Call us and we can get you what you need.

Bearing Quality Genuine Lignum/Vitae is know as Guaiacum Sanctum.(Officinale Guaiacum 1.37)

These names have been central to the bearing industry since Christopher Columbus.

As the resource became scarce a wood known as Argentine Lignum/Vitae has surfaced. Although we have never seen any reference to this material in any known engineering manuals some have bait & switched this material as genuine. Always ask for original Genuine Lignum-Vitae as the only known specified material for under water hydro-or ships bearings.

The following do not have the same properties as Authentic Lignum-Vitae.
Bulnesia Sarmientoi, known commercially as Argentine Lignum Vitae, is related to but not the same as Bulnesia Arborea, known commercially as Verawood.

[captsct]

I can't say exactly which version they are selling, but it was greenish, extremely dense, heavy, tight grained, and had a waxy feel to it. Not something I would want to be hit over the head with. If it proved to be the true stuff, the pen blanks probably would make decent pins, but there should be enough left after cutting the sheaves to make pins from the plank scraps. when I get back over there I'll ask if they know, but I'll guess they don't and/or say it's the real thing to make a sale.

[jalmberg]

Continuing my block-building education, I've just finished making a pair of cheek blocks that I'm pretty darn happy with.

http://3.bp.blogspot.com/-tSNSb1vwNss/TfUwns-tDvI/AAAAAAAADy4/zjvuy-VjzrA/s400/DSCN4516.jpg

More details here: Reefing blocks (http://www.unlikelyboatbuilder.com/2011/06/importance-of-being-beefy.html)