Accepting a tow

[Resolution]

The Hot Liquid thread has touched on a subject that might be important to any of us one day: how best to rig lines to accept a tow?

Obviously in rough weather the snatch loadings on a tow can be enormous, with chafe and vanishing cleats the outcome. So what are the least bad ways of rigging for a tow, and what preparations should one make in advance?

On my mid-weight 40 foot yacht I think I would (if I had time):
1. make a bridle out of a long hard wearing mooring line by making a bowline on the bight at mid point, bringing the two ends back in through the fairleads and tieing off on the two bow cleats.
2. To support the cleats I would take two non-stretchy lines (eg spinny sheets), and on each side of the boat tie one end round the aft vertical of the bow cleats, run back tightly to the mid-ship cleats and then back to the genny sheet winches and wind up really tight.
3. Attach the main tow rope to the bowline on the bridle.

Queries:
How best to anti chafe?
Knots in each case?
Is it safe to run something round the keel-stepped mast? What horizontal strength does it really have?

 

[Koeketiene]

When we were towed in by the RNLI 3 years ago, I led their tow over the bow roller and attached it to the windlass.
RNLI quite happy - towed us in making 7kts - never budged.

 

[sarabande]

there are some windlass mountings which would certainly not stand those kind of towing loads. You must have yours beefed up for this possibility ?

 

[prv]

When we were towed in by the RNLI 3 years ago, I led their tow over the bow roller and attached it to the windlass.
RNLI quite happy - towed us in making 7kts - never budged.

Was it you in the other thread saying you were towed in very light conditions? I'd have thought anything would be ok towing by the bow cleats/windlass/etc in those circumstances - the RNLI use a long and heavy tow rope that's mostly in the water, so it's not twanging and snatching. Bit different in the famous Force 10 off Dover.

Pete

 

[Seadog17]

If possible I would be inclined to attach the tow line to my anchor cable and then let out a few fathoms of chain. The weight of the anchor and cable would then act as a shock line and reduce the snatching, which causes most of the problems with towing.

 

[prv]

How best to anti chafe?

As well as the usual wrapping in hoses/rags/etc, I've heard that greasing the rope can help with chafe. I carry tallow aboard (old-fashioned rig involving greased leather) and would use that, but otherwise I presume seacock/stern gland grease would do, or even butter or cooking oil.

Knots in each case?

I might do a climber's figure-8 for the central loop on the bridle. Each leg would run back round cleats to the winches as you describe - I wouldn't use separate pieces of line though as you describe, one all the way. Also would just put a turn or so round each cleat, to take some of the load but still allow the line to creep slightly so that everything can take up the tension evenly.

If you have a length of line from (say) bow cleat to midships cleat, firmly secured at each end, how is the winch going to put any tension into that? Such a line won't do anything until the bow cleat is ripped out of the deck.

Is it safe to run something round the keel-stepped mast? What horizontal strength does it really have?

Dunno - I would be a bit wary unless it was a solid timber mast. On my own boat though, I would be prepared to put part of a towing bridle round the tabernacle - it's a substantial piece of ironmongery well fixed to the deck with big bolts (not to mention a lot of sikaflex). Certainly way more strongly mounted than my little winches are. Likewise the "faux" samson post on the foredeck; faux because it's merely bolted to the deck, not mortised into the keel - but they are fairly chunky bolts.

Pete

 

[Deleted member 36384]

The Hot Liquid thread has touched on a subject that might be important to any of us one day: how best to rig lines to accept a tow?

Obviously in rough weather the snatch loadings on a tow can be enormous, with chafe and vanishing cleats the outcome. So what are the least bad ways of rigging for a tow, and what preparations should one make in advance?

On my mid-weight 40 foot yacht I think I would (if I had time):
1. make a bridle out of a long hard wearing mooring line by making a bowline on the bight at mid point, bringing the two ends back in through the fairleads and tieing off on the two bow cleats.
2. To support the cleats I would take two non-stretchy lines (eg spinny sheets), and on each side of the boat tie one end round the aft vertical of the bow cleats, run back tightly to the mid-ship cleats and then back to the genny sheet winches and wind up really tight.
3. Attach the main tow rope to the bowline on the bridle.

Queries:
How best to anti chafe?
Knots in each case?
Is it safe to run something round the keel-stepped mast? What horizontal strength does it really have?

Anti Chafe
Never thought about greasing before as prv advises, but why not. I have 2 ft lengths of 3" fire hose which I use as anti chafe. It has a slippy lining inside and a tough anti abrasion cover on the outside. I have found it ideal for warps. This winter saw some quite heavy surging on my own yacht (12 ton) and the hose worked a treat.

All parts of the bridle that are subject to wear have the hose sections fed over them and cable tied in place. On one occasion, when I had to haul the yacht of a lee harbour wall with a kedge, this was not sufficient. The hose section was then stitched through the line to hold it in place.

I have to wrap my forestay bottle screw and clevis pins / toggles in fire hose that I have split open. I have quite thick heat resistant wrap (for exhaust pipes) that I could supplement the hose with.

Knots and Heavy Weather Bridle
I use my kedge warp as a towing bridle, 20 mm multi plait nylon. The warp is doubled to create two running parts. The bight in the middle of the line is then tied into a figure of eight which makes a loop right at the mid section, the towing eye.

The towing eye is dropped over the bow and the two running parts are brought down the port and starboard sides to the primary winches.

I use two brest lines, port and starboard to tie back the towing eye to the port and starboard cleats on the bow. The lines are attached with round turns and two half hitches because they do not work back and fore.

I use two additional lines on the towing eye back to the anchor windlass, port and starboard and tie onto the cathead and the chain gypsy.

The bridle running back to the primary winches is kept free from the coach roof by using the mid ship cleats, which is hauled slightly to the side using 10 mm, 3 strand nylon sail ties.

The bridle is adjusted on the two lines running back to the sheet winches to centralise the towing eye. The 4 other lines from the towing eye are adjusted to give more or less, even lengths, and made off. The idea is that stretch on nylon long length of the bridle is sufficient to tension up the sorter lengths, so I am not worried about the sorter lines initially.

The main issue for me is the towing eye over the bow being free to move. In a big sea I will probably damage the pull pit central, vertical bar, the top rail and the bi-colour navigation light, although that can be shipped.

There is nothing realy to secure the towing eye too. I have looked at feeding lines under the rollers and over the loop, which would be OK in moderate conditions but might not be in heavy conditions. The chafe from the cheeks would be very severe as well as well as being quite restrictive as far as access is concerned. I don't really have a good solution for this. The towing eye is constrained somewhat from the lines onto the port and starboard cleats.

Ideally I would like a stem head fitting with a central fair lead and the forestay attachment on top. However, that won't change as I have what I have. I have considered a forward facing fairlead build onto the gunwale at the bow, just offset to one side. My gunwales are raised off the deck and about 75 mm thick at this point. This is not a priority though, by far.

Light / Medium Weather Tow Bridle
A 16 mm nylon brest line, doubled over with figure of eight to create the towing eye (dropped over the bow) and then the two ends fed through the closed bow fairleads (built into the gunwale GRP) and tied together in a figure of eight. Chafe protection has to be thick and good as the line passes through 90 degrees over the closed fairleads.

I have rigged the above two harnesses to test them out and used the heavy weather one for a sea anchor drogue. It was bit OTT but I think it would have come into its own if we had to be taken in tow in those conditions.

Keel Stepped Mast
I would use a keel stepped mast but I would also use the primary sheet winches in heavy weather. If using a keel stepped mast (or any tow), it is absolutely imperative that the towing eye can not slew round and away from the bow. If the boat ended up side on to the tow vessel, with a tow line running at right angles from the mast, straight to the towing vessel, it could be very serious indeed.

For example: a light yacht takes the line through the bow roller and onto the mast. The loads become high for whatever reason, rips out the pin over the bow roller, pull up the pull pit, tear out the guard rail stanchions, the helmsman over steers and now the pull is on the base of the mast at right angles. Not a stable position to be in.

 

[Seven Spades]

Trying to attach a tow rope in a F10 to the anchor chain sounds interesting, how do you hang on whilst doing that? It sounds a goos idea in principal, but in reality I think that the movements of the two boats and the pitching and rolling of the damaged vessel will mean that any tow rope will need to be attached very quickly and I doubt that you would have either the ability nor time to do that.

 

[Seadog17]

Trying to attach a tow rope in a F10 to the anchor chain sounds interesting, how do you hang on whilst doing that? It sounds a goos idea in principal, but in reality I think that the movements of the two boats and the pitching and rolling of the damaged vessel will mean that any tow rope will need to be attached very quickly and I doubt that you would have either the ability nor time to do that.

I would think that whatever way the tow is picked up, someone is going to have to work at the bow anyway.
If the anchor was prepared over the stemhead and ideally, a wire strop and shackle fitted behind the anchor shackle, over the chain, then it would be a fairly quick job to attach the tow to the other end of the strop when help arrived.
Possibly a drogue over the stern would help in this situation. I do not know, only recently bought my first yacht and started learning, so what I suggest may be totally impractical, but I think I would consider that method, if I should ever need to seek help.

 

[prv]

Trying to attach a tow rope in a F10 to the anchor chain sounds interesting, how do you hang on whilst doing that?

Legs wrapped round the jackstays and/or pulpit bases, I'd have thought.

Pete