How to specify shore lines?

[Flobble]

I'm about to buy new shore tie lines for my boat, a 52ft, 15t catamaran and would appreciate guidance on what to buy.

The intended use case is overnight stops in bays where it isn't viable to swing freely. Storage when not in use will be in bags in a locker.

Assorted online guides from rope manufacturers, much searching and reading others experiences are suggesting the following:

• 2 lines of minimum 50m, ideally 75m or even 100m each.
• Polypropylene (floats) and in a visible colour (yellow or white)
• 16 or 18mm diameter, which means breaking strength of 3,400kg to 4,000kg (varies by manufacturer)
• A 100m length would weigh ~14kg, which is manageable.
• Need to add anti-chafe protection against rough rocks.

Could be €750 - 1,000 in cost depending on whether I opt for 3-strand a braid, so I don't want to get this wrong!

FWIW, my anchor chain is 10mm galvanised, and ~2x stronger than this.

Thanks!

[wrwakefield]

Flobble,

We carry shore fasts as we sometimes have to use them for some of the same reasons.

They need to be stronger than you might first think depending upon where you sail.

We use 6- 100 ft. lengths of 3/8 in. bright colored Spectra line [14,000 lbs tensile] with soft eyes at both ends for cow hitching or soft shackling in series- stored [flaked] in mesh anchor rode bags.

We also use a combination of chain and/or galvanized cable chokers for lassoing rocks, or webbing tow/lift lines for trees.

There is lots more info with many reference links on our Ground Tackle page [search within page for ‘shore lines’]

https://svdenalirosenc43.blogspot.co...-includes.html

There is also much more detail- including deployment methodologies- in the following blog post: [Don’t worry; no ads or begging… just sharing…]

https://svdenalirosenc43.blogspot.co...horefasts.html

In case any of this is useful.

Cheers, Bill

[Mal Reynolds]

FWIW, on my 50,000 lb (fully loaded) mono, I carry a pair of 300' lines of 1/2" spectra (30,000 lb tensile) and a pair of 40' 3/8" 7x19 wire cables for rock ties.

Plus a 300' polyester double braid line that is also used for a drogue or towing.

Someone also advised carrying extra chain so the lines don't chafe over the rocks.

If you haven't seen this, here is Skip Novak setting up shore ties down in Tierra del Fuego:

https://www.youtube.com/watch?v=pjZVVstkdQU

Looks like he used at least 1" polypropylene. He does mention the rock chafing risk. Note also chafe guards at his hawse pipes.

[Dockhead]

I use old halyards -- 12mm double braid, about 6 tonnes breaking strength.


I don't feel the need for more strength than that as I think my anchor will have long since been pulled out of the bottom before I reach 6 tonnes of force.


I hate shore ties -- they prevent the boat from finding equilibrium with her anchor rode and create a real risk of pulling the anchor out if there's much force.


I came to Greenland a few years ago prepared to use shore ties as everyone does since the bottom slopes steeply and feasible anchorages are very deep. I managed to avoid it by accepting very deep anchoring. I'd rather have a whole lot of heavy chain than rely on shore ties.

[wrwakefield]

Originally Posted by Dockhead

I use old halyards -- 12mm double braid, about 6 tonnes breaking strength.


I don't feel the need for more strength than that as I think my anchor will have long since been pulled out of the bottom before I reach 6 tonnes of force.


I hate shore ties -- they prevent the boat from finding equilibrium with her anchor rode and create a real risk of pulling the anchor out if there's much force.


I came to Greenland a few years ago prepared to use shore ties as everyone does since the bottom slopes steeply and feasible anchorages are very deep. I managed to avoid it by accepting very deep anchoring. I'd rather have a whole lot of heavy chain than rely on shore ties.

Agreed!

Shorefasts are the last resort, and only when absolutely necessary [which isn’t very often…]

Cheers, Bill

[fxykty]

Originally Posted by Flobble

I'm about to buy new shore tie lines for my boat, a 52ft, 15t catamaran and would appreciate guidance on what to buy.

The intended use case is overnight stops in bays where it isn't viable to swing freely. Storage when not in use will be in bags in a locker.

Assorted online guides from rope manufacturers, much searching and reading others experiences are suggesting the following:

• 2 lines of minimum 50m, ideally 75m or even 100m each.
• Polypropylene (floats) and in a visible colour (yellow or white)
• 16 or 18mm diameter, which means breaking strength of 3,400kg to 4,000kg (varies by manufacturer)
• A 100m length would weigh ~14kg, which is manageable.
• Need to add anti-chafe protection against rough rocks.

Could be €750 - 1,000 in cost depending on whether I opt for 3-strand a braid, so I don't want to get this wrong!

FWIW, my anchor chain is 10mm galvanised, and ~2x stronger than this.

Thanks!

You’ve got a relatively light catamaran, so don’t load it down with something you’re not going to use very often.

Our solution was two separate shorelines, each 80m of 10mm Dyneema lines and stored in stainless steel line spools. We put eye splices into each end. For the shore connection we use heavy duty 6m 150mm polyester lifting straps - easier to handle than chain or wire. If there’s going to be surge and we reduce shock loads on our cleats we add shock absorbers.

Line is yellow UMHWPE purchased from Greenline Fishing https://greenlinefishinggear.com/products/acera-products/amundsen/. It floats, is easy to splice, and strong enough so you can use small diameters.

Line spools and shock absorbers are from Easyroll https://easyroll.de/en/products/. The company now sells complete sets including UHMWPE line and it looks like the cost is similar to what you’re looking at. The spools make it super easy to store, deploy and retrieve the shorelines. We made spool covers ourselves using the Sailrite RV wheel covers design, but Easyroll sells them too.

[Flobble]

Thank-you all - very helpful.

I'm particularly enamoured with the fxykty solution.

[Dockhead]

Originally Posted by Flobble

Thank-you all - very helpful.

I'm particularly enamoured with the fxykty solution.

That's by far the easiest way to handle long shore tie lines. It's quite common on Arctic boats to see big spools of polyprop on deck for this purpose. What Fxykty is showing is a common Baltic setup used for stern anchor lines. Baltic sailors often use flat webbing rather than rope, which could be a good solution here. You can buy the spools, and the webbing if required, from chandleries which cater to Baltic sailors, like svb24.de, or one of the Swedish ones.



I would not, personally, use dyneema for shore ties. I don't think you need all that much strength. Arctic sailors normally use polypropelene, which is probably 10x cheaper than dyneema.

[Flobble]

Originally Posted by Dockhead

I would not, personally, use dyneema for shore ties. I don't think you need all that much strength. Arctic sailors normally use polypropelene, which is probably 10x cheaper than dyneema.

Indeed, much cheaper, and also has the advantage of built in shock absorption. But it's also bulkier for the same strength.

Which brings me back to my original question - how to determine what strength is required?

[Dockhead]

Originally Posted by Flobble

Indeed, much cheaper, and also has the advantage of built in shock absorption. But it's also bulkier for the same strength.

Which brings me back to my original question - how to determine what strength is required?

Well, if you intend to hold on in a howling storm blowing offshore, then you would probably want them to be as strong as your anchor rode.


But I don't think that would be a common scenario. Most often you use shore ties to keep the boat from swinging, when you've got your bower anchor dug in on a slope -- common situation in areas with very steeply sloping bottoms. Because if it swings, the anchor will pull out.


For that use, I think a fraction of the strength of your anchor chain would be enough. If the wind is getting you abeam, your anchor will be pulled before all that much force can be applied. If the wind is coming directly offshore, then that's different, but in that case, if the line breaks, you will be go harmless out to sea, so I don't think you care about a huge margin of error.


That was my logic, anyway.



I've used shore ties from time to time, but during a whole summer cruising the Arctic I managed to never use them even once. I was in uncharted waters (Scoresby Sund, NE Greenland), so I had to choose anchorages by first principles rather than looking at a chart. I often anchored near the mouths of streams, where I could count on sediment mitigating the otherwise huge slope. Or in the middle of coves at the deepest point. This required sometimes all my 100m of chain and very short scopes but it worked well, including in one pretty good storm.

[Mal Reynolds]

Originally Posted by Flobble

Indeed, much cheaper, and also has the advantage of built in shock absorption. But it's also bulkier for the same strength.

Which brings me back to my original question - how to determine what strength is required?

With broad shore line angles and gale force (katabatic) side winds the loads can be very high. It's just how the physics and trigonometry works. Many times higher than swinging freely at anchor. John Harries at morganscloud.com has done the math. He says a rule of thumb is 50% of displacement (monohull). Might be even higher for a multihull. This is informed by his experience in Greenland, Labrador and elsewhere when anchoring on a single anchor wasn't realistic with tough weather bearing down. I think similar conditions are in Tierra del Fuego, South Georgia. Other areas are no doubt less demanding.

If you are planning high latitude cruising, morganscloud.com is well worth the subscription cost.

For fun, here is Skip Novak at South Georgia:

[Flobble]

Thanks for the Morganscloud link; I found this on the free section of the site: https://www.morganscloud.com/2010/06...efast-systems/

There's much more behind the paywall too.

[thinwater]

Originally Posted by Mal Reynolds

... For fun, here is Skip Novak at South Georgia:

"He who would go to sea for pleasure would go to hell to pass the time."


J. Boyd Shellback, 1899.

[Dockhead]

Originally Posted by Mal Reynolds

With broad shore line angles and gale force (katabatic) side winds the loads can be very high. It's just how the physics and trigonometry works. Many times higher than swinging freely at anchor. John Harries at morganscloud.com has done the math. He says a rule of thumb is 50% of displacement (monohull). Might be even higher for a multihull. This is informed by his experience in Greenland, Labrador and elsewhere when anchoring on a single anchor wasn't realistic with tough weather bearing down. I think similar conditions are in Tierra del Fuego, South Georgia. Other areas are no doubt less demanding.

If you are planning high latitude cruising, morganscloud.com is well worth the subscription cost.

For fun, here is Skip Novak at South Georgia:

I think the physics say that your anchor will be pulled out in gale force side winds, and your boat will be dashed on the rocks and you and your crew will die.

I think you just don't want to be in that position. Trying to hold your boat beam-on to the wind and seas seems like sheer madness to me, and the risk of that happening due to an unexpected wind shift is one of several reasons why I avoid shore ties wherever possible.

In a whole summer in the Arctic, in a place with extremely few feasible anchorages, I nevertheless always found a way to anchor with the wind blowing offshore. In a place with no rescue services and ice floating in the water, I took extreme care planning where and how to anchor, studying the weather, etc.

[El Pinguino]

Originally Posted by Mal Reynolds

FWIW, on my 50,000 lb (fully loaded) mono, I carry a pair of 300' lines of 1/2" spectra (30,000 lb tensile) and a pair of 40' 3/8" 7x19 wire cables for rock ties.

Plus a 300' polyester double braid line that is also used for a drogue or towing.

Someone also advised carrying extra chain so the lines don't chafe over the rocks.

If you haven't seen this, here is Skip Novak setting up shore ties down in Tierra del Fuego:

Looks like he used at least 1" polypropylene. He does mention the rock chafing risk. Note also chafe guards at his hawse pipes.

Ah. the infamous Skip Novak 'How I took over an entire anchorage and denied anyone else access' video.
Moving right along - having spent 16 years of the last 21 in Patagonia I use 12mm polyprop stowed in 'Bolsas para Verdura' which cost about $CH500 in Pto Montt and last about 2 years. My ropes are the original from 2004. I 'freshen the nip' now and again.

I've never ever had to use wire to tie up to rocks.

Mas aqui - https://www.docdroid.net/bO63FbL/202...anchorages-pdf
Puerto Maxwell is at page 126.