Rope-Stropped Blocks for Boom Vang

[Julie Mo]

I'm making a full sized set of wood blocks with intentions of making a boom vang.  One block will have three sheaves, the other two.  This is what I have so far

 

On the double block, I want something like a becket on one end.  The other will look something like the triple above on the other end.  I made up two eyes for the double block but when I went to see how it would look, with an eye at either end, it looked unwieldy. 

 

I saw this online and wondered if I made up an eye splice for one end of the boom vang line and secured it to the rope, like below, rather than having a second wood eye.  Would this be something you would have seen on an old sailing vessel?

 

[mtaylor]

Very impressive work, Julie.   The block looks fantastic.

[puckotred]

here you see a couple of ways to do it: hook and thimble, thimble and strap and thimble and thimble.

[davyboy]

Hi Julie Mo,that is an impressive block. Your lower block does require a Becket at both ends. A suitable length of rope had the ends spliced together forming a ring with an iron thimble lashed in at each end of the block. One for the hook the other for the falls. Hope your good at splicing . Also,these rings were served overall.

 

FWIW,the largest vang blocks fitted were a 9" double and a 9" single.  This on 1st,2nd and 3rd rate English ships,can't speak for other lands.

 

Looking forward to seeing the final result,I know you will make an excellent job of it.

 

Dave 

Edited June 24, 2018 by davyboy

[JerseyCity Frankie]

I can’t let this go by without saying that this guys book is FULL of ridiculous rigging innacuracies and this example is probably the worst one. NOBODY is ever going to rig a purchase as this illustration indicates. As in NEVER, it simply doesn’t exist. The second block and tackle hanging under the existing block and tackle is preposterous. I put this very image on a Facebook rigging page , everyone had a laugh, and then Brion Toss weighed in on it, then put it on his own website. Honestly: this guys book is a trainwreck. 

Here’s Brion Toss commenting on it: http://briontoss.com/index.php/2018/03/14/extravagant-purchase/

Edited June 25, 2018 by JerseyCity Frankie

[wefalck]

I don't know the book, from which the drawing came, but looking at made me scratch my head Mechanically it doesn't make any sense ...

 

I was going to comment that whipped blocks, i.e. from which the running part cannot be detached, would be rather uncommen in real running parts of the rigging. In case the running part becomes damaged from use, one would have to unstrap the block and replace the whole splicing, serving etc., rather than simply replacing the running line. On backstays it would, however, make sense, as the movement of the running part is only limited, with not so much wear.

 

For blocks with eyes at both ends, I think there would be long splice alongside the block and the eyes tied off with yarn at both ends. I think either Lever or Steel have drawing that shows that, didn't check.

Edited June 25, 2018 by wefalck

[puckotred]

 

The drawing is shown here as different ways to strop blocks, not as how to rig...

[JerseyCity Frankie]

Rope stropping blocks, for functioning rigging, is difficult. The difficulty is in having the strop as tight as possible around the block, so tight that no force encountered on the ship could ever cause the block to slip out of the strop. It’s very easy to put a rope grommet over a block and seize in some eyes, but it’s difficult to do this in a way that keeps the strop as tight as it needs to be.

the Strop is a circle made of rope. Most often it is a Rope Grommet (which is one strand of rope laid up upon itself three times) but it can also be a length of rope that has its two ends Short Spliced together.

here are some photos I collected of the process: 

 

The first photo shows a double block with the strop around it and a Spanish Windlass made of two belaying pins and an iron rod being used to close the neck of the seized eye. The blue and white thin strapping through the sheaves and in the Spanish Windlass  is Dyneema, a nearly indestructible man made material. It’s holding the block in place. The part of the strop  out of frame of the photo at the top will have a block and tackle on it pulling the strop as tightly as possible. The Spanish Windlass closes the eye and at the point this photo was taken they have not yet put a seizing on at the neck of the eye.

here is a nice diagram showing a single strand being laid up into a Grommet:

Here is a guy on Picton Castle with two blocks being stropped. Note all the tackle in use to pull the Grommets as tight as possible, rest assured he has made that line as tight as humanly possible, the bench is bolted to the deck. His left hand is on one block and the other is between the camera and his crotch. At this point he’s ready to seize the eyes. He will construct a Spanish Windlass as shown in the first photo above, to close the eye prior to seizing the neck.  The tackle holding the strop tight is not removed, the seizing of the eye happens with the strop as tight as possible. So it is VERY DIFFICULT to close the eye, and you could not close it without the Spanish Windlass. This photo makes it clear that the diameter of the Grommet must be carefully planned ahead of time to make sure the proportions of the eye and block are correct. Too small and the eye is too small, too large and the neck is long and you risk the block wiggling out eventually in the future. 

Edited June 25, 2018 by JerseyCity Frankie

[amateur]

I know that almost al Dutch inland water ships have iron stropping at these blocks. Never seen a pic showing rope-stropping. 

 

Jan

[Roger Pellett]

The fictitious tackle above is an example of relying too heavily on old models as primary evidence for constructing historically accurate models.  This is especially true of rigging which being fragile is often repaired or completely replaced.  The book from which the drawing was taken documents the models of three vessels in the Statens Sjohistoriska Museet in Sweden.  The author makes no attempt to note anachronisms or physically impossible arrangements limiting the book’s usefulness.

 

Roger

[druxey]

I have to agree with Roger's remarks. I've seen historic models with 'restored' or re-jigged rigging that is patently wrong. One I examined recently had an original line expended by wrapping it repeatedly around the heel of the bowsprit!

[Julie Mo]

The strop is a rope grommet.  I saw a formula for determining the length necessary to make the correct length strop.  Problem is I measured the triple block and eye and applied the formula.  It worked great for the triple block.  But was too short for the double with two eyes.  Should have measured that first.

 

When I fashioned up the double block with eyes at either end, it just looked wrong.  I tried to find pictures of one actually being used on a sailing vessel but no luck.  I'll cut me some more rope for the other strop and if it ain't lookin' right, have me some rum. 

 

Thanks for the help!

Edited June 25, 2018 by Julie Mo

[jud]

I would do it the following way Julie, Just use an eye on the two block on the intended inside, side, no thimble, go ahead and use the thimble on the outside where some movement causing wear may take place. The tackle line should be led through the eye and laid back against itself and seized tight, close up to the eye. When you rig it run the line the same as it was made up in the new roll, less twisting that way. Yep it does make a difference when using twisted natural fiber. Block looks nice Julie.

 

Edited June 26, 2018 by jud

[wefalck]

BTW from which book did the contested drawing actually come from ?

[puckotred]

weflac, one of Lennart Petersson's books. "Rigging Period Fore and aft Craft" I suppose...

Edited June 26, 2018 by puckotred

[wefalck]

Thanks, I thought so, but wanted to have it confirmed. Good thing that I don't have this book

[jhearl]

I have this quaint habit of looking at real ships when I want to know how something is done. Here are a few examples:

 

Cheers -

John

[Julie Mo]

Well, I tried to muscle the two eyes using the same size strop as the triple.  I ain't that strong.

Went ahead and finished it because I'm bullheaded.  Temped in a bowline where the eye splice will be.

I'll need to buy some more rope to make a proper sized strop, plus for eye splice lines to go where who knows?

[jud]

Looking good, when you redo it, leave the thimble out of the inside of the double block. Put an eye into the end of the running tackle using a short back splice. Then place over the loop on the inside, side of the block, go to the other end for the bitter end and drop it through the block loop, pull it through and re-rig, the connection will resemble a square knot and can easily be undone, you will have a compact professional looking and secure non wearing connection at the inside of that double block. Are you going to use this, or as months ago you were wondering about sources for such rigging for decorative purposes. I like hanging useful things on the wall such as this, find such decoration comfortable.

[JerseyCity Frankie]

It’s hard to find good books on the subject of Marlinspike Seamanship but there are two classics and a modern contender:

first and best is The Ashley Book of Knots. By Clifford Ashley and comprehensive on the subject of knots and cordage. Kinda pricy. But worth every penny!

 

then there are Hervey Garrett Smiths two books, which are realy the same book but one has additional material, The Art of the Sailor and The Marlinsspike Sailor. These books have the best illustrations of any knot book and cover several rope related craft projects that are fun and easy to build make or tie. Very inexpensive and if you are stropping blocks for fun, you’re going to LOVE this book. 

 

Finaly Brion Toss’s Complete Riggers Apprentice. Excellent text and illustrations covers every marlinspike concern any yacht owner could need to know about. This book will have sailing related material you won’t NEED to know but I include it because it’s got so much worthwhile info in it and a very good knot tying tutorial for the basic sailors knots.

Here’s Brion Toss taking you through the steps of tying the Round Seizing:

Here’s Clifford Ashley describing how to use a Spanish Windlass to close the neck on a rope strop.

Here’s Garrett Smith describing the use of the Marlinspike as a lever for putting the turns of a Round Seizing on supper tight.

Edited June 27, 2018 by JerseyCity Frankie

[Julie Mo]

I have the Marlinspike Sailor and refer to it whenever I'm trying to make rope do what I want it to do.  I also have the Splicing Handbook by Barbara Merry.  I've had both for quite a while. 

 

When my dad had his sailboat, I made up a rope kit with fids, marlinspike knife, pusher, twine, etc.  That bag followed me long after he and the boat were gone.  Still have it, along with spare lines from the boat.  Maybe one day I'll be able to use them on my sailboat.  Here's to dreams coming true...