Towing and cleats

[FlyingDutchman]

Reading the thread on towing other boats, the question came to my mind if cleats are strong enough to tow another boat?
My boat has two cleats that we use to put on the mooring lines. Are these strong enough to tow another boat or would they be ripped out of the deck? What is the best way to tow, on one cleat or on both? what is the best way to attach the towing line?

 

[sailorman]

Reading the thread on towing other boats, the question came to my mind if cleats are strong enough to tow another boat?
My boat has two cleats that we use to put on the mooring lines. Are these strong enough to tow another boat or would they be ripped out of the deck? What is the best way to tow, on one cleat or on both? what is the best way to attach the towing line?

tow from primary winches or make up a bridle to spread the loads

 

[FlyingDutchman]

Hi Sailorman, It is a mobo so I don't have winches...
What is a bridle?

 

[sailorman]

Hi Sailorman, It is a mobo so I don't have winches...
What is a bridle?

you have the wrong boat then

http://www.boatingsafety.com/tow2.htm

 

[Gordonmc]

By a bridle Sailorman means a line or series of lines which will spread the load from towing to as many strong points on your boat as are available.
If you have stern cleats for mooring, for example, a line from those to the bow cleats, made off hard, would help. Even better would be a line or heavy webbing strop round the transom.

 

[maby]

And use something with a bit of spring in it to make the bridle - to absorb the shock when you take up the tension and it snatches. Nylon rope that has some stretch, or a mooring snubber.

The same considertions apply for being towed as for doing the towing - always distribute the strain across multiple points - at least put a bridle between the mooring cleats on both sides and, if possible, run further lines to another pair of cleats.

 

[Deleted member 36384]

Cleats (or bollards) can be be strong enough to accept a tow or take a tow if designed and installed properly.

Typical design features would be a solid mounting base below the cleat horns (or bollards) that is wider than the cleat width, has 4 to 6 bolts to fasten down and has a large backing plate on the underside. The backing plate, in my opinion, is better bonded to the deck underside (as opposed to just sealed and clamped), be at least 4 x the diameter of the bolts thick (if hard wood) and at least double the size of the cleat mounting base.

There are design features for the deck holes that the bolts will pass through depending on the material e.g. Balsa Cored FRP, solid FRP, wood or steel.

There are yachts around in GRP that can be lifted by their cleats and some obvious examples of steel boats with welded cleats and bollards that with similar strength.

If you have access to the underside of the deck and cleats and can see the mounting arrangement, then an opinion could be formed about their suitability for towing.

My own yacht is 41 feet and has 10" cleats which have small, narrow mounting base, 2 mounting bolts, solid 20 mm thick GRP deck (at the mounting point) and a small backing pad. They are very strong for mooring but would be undersized for heavy towing operations. Some designers would suggest a cleat size around 14" for a yacht at 41' for heavy towing operations.

So it is unlikely that most yachts, with typical cleat installations, have suitable bow (or stern cleats) for heavy towing operations, but fine for a gentle tow on a calm day.

The link below from this PBO forum is a recent posting on towing practices and bow cleats which is worth a read: -

http://www.ybw.com/forums/showthread.php?t=299811&highlight=Tow,+towing

 

[FlyingDutchman]

Many thanks for all your information!

The cleats on my boat don't meet the design standards as mentioned by Blowingoldboats.
They have no mounting base under the cleat horns. They are just bolted through something like 20mm GRP and inside are only washers and nuts.
Strange, I thought that a Norwegian built boat (Skagerrak 720) would be better in these aspects, even though it is only a small (23') boat.

If I have to tow another boat I will use a bridle and be very careful, applying the full 60 hp will certainly leave my boat without cleats!

Glad I asked here.

 

[maby]

P.S. the idea of the bridle was not very clearly explained. You fix a relatively short (and preferrably springy) line between your two cleats and then attach the tow line to the bridle with a loop that is free to slide along the bridle - that way the load will always be distributed evenly across the two cleats. If the tow line is fixed hard to the bridle, it defeats the object since all the force can still be transferred to a single cleat.

 

[rob2]

that way the load will always be distributed evenly across the two cleats.

Well, shared though not always evenly. There will always be more strain on the straighter of the two legs due to the friction of the loop on the bridle. When the RNLI use a bridle, it has an eye in the centre for attachment of the tow, but their attachments are definitely designed for the task. They suggest that the bridle on a yacht should be attached at all available strong points, so for a sailing yacht the bridle is taken to the foredeck cleat, on to the main winches and the tails made off to the aft mooring cleats. The other consideration is how best to avoid chafe through either the bow roller or fairleads. A longish bridle should behave itself, but a short one may snatch vertically.

Rob.

 

[mdonnelly]

As an aside; 2 years ago had the unfortunate experience of being towed into Portpatrick by RNLI just after LW. I draw 1.5 m but was towed into the inner harbour eventually. First time ever had a tow so inexperienced. Towing line was passed through fairlead, 2 curved pieces of 1cm diameter stainless rod and attached to bow cleat. Later noticed that one of the curved pieces of the fairlead had been distorted and that the aft arm of the cleat had a slight upward bend. The forces were probably very large but no problems at deck level.

 

[William_H]

Towing

As towing boat you have control of the throttle which means also control of much of the strains of the tow.
Be very gentle if not for your own boat then for the towed boat.
Be very careful to ensure that the boat being towed is ready to take the strain. We have one club member with the top of his finger missing. The club RB driver thought there was some urgency in getting the towed boat pulled clear. He gunned the engine and the person attaching the tow rope still had a finger under the rope. (not finally cleated) 140HP Mercruiser inboard outboard leg.
We use a bridle from stern cleats the actual tow rope having a pulley onto the bridle.
However this is not the best arrangement. If you look at tug boats they always have the tow line pulling point well forward of the transom ie near the middle of the boat. You will find if you try to pull a heavy boat especially one stuck on the sand that the pull on the transom will steer your boat. Or at least deny you steering. A pull from the middle of the boat does not affect the tow boats steering. However you must then accept a tow line that sweeps across the aft deck. good luck olewill

 

[BobPrell]

We use a bridle from stern cleats the actual tow rope having a pulley onto the bridle.
However this is not the best arrangement. If you look at tug boats they always have the tow line pulling point well forward of the transom ie near the middle of the boat. You will find if you try to pull a heavy boat especially one stuck on the sand that the pull on the transom will steer your boat. Or at least deny you steering. A pull from the middle of the boat does not affect the tow boats steering. good luck olewill

The same goes for the towed boat. If the line is fixed at the bow, the towed boat will not be able to steer.

I am always amazed when I see peeps put a towline onto their bow cleat with a bowline, which cannot be undone or lifted off a cleat under strain. They have completely surrendered control of their vessel to the towing vessel. The only way they can bail out of the process would be to cut the line.

 

[FlyingDutchman]

Again, thanks for sharing your insights.

Gentle and careful are the words!
Also, the safety aspect is a very important one. We tend to forget what forces can be introduced by the engine and the masses involved.

 

[William_H]

Towing

Brings to mind a sad little story of 2 friends one towing the other. Really benign conditions with no wind hence the tow. They got into the entrance to the marina jetties and towing boat called for removal of the tow line (he owned the rope). Newby on the towed boat couldn't get the line off the cleat. Helper on the towing boat then released the line and dropped it into the water. The newby then finding the pressure off released the tow line also into the water. Result was the loss of a long piece of expensive spinnacker sheet which being polyester rope sank like a stone. I got involved trying to drag a grappeling hook for the rope but no joy.
Communication and care needed. olewill

 

[grumpy_o_g]

One other thing to remember (which seems pretty obvious but I've seen people forget it) is just how effective your rudder is (or isn't) at towing speeds. Outdrives and outboards are okay, displacement mobos and most sailing yachts generally too, but a planing boat on shafts doesn't always have the rudder authority to overcome the towed boats influence or to control the tow as the towed boat very well. There are one or two yachts that are not so good either as they have a massive inbuilt directional stability and not such a good turning circle, especially some older long keel or Keel and skeg designs - crabbing cross-tide with that sort of boat as the towed boat can be entertaining, especially if the tow is right from the bow (I used to work in the yards in BoC as a teenager as well as on the club launches so spent a fair bit of time towing).


Couple of things I haven't seen mentioned. Don't just use the full length of the line automatically - especially in a swell. The idea is to adjust the length of the line so that both boats ride up the front of the swell and then back down the other side at the time - otherwise you can end up with the tug climbing slowing up the wave while the towed boat is surfing down the back at the same time. It's not so much the danger of the two boats colliding as that the line goes alternately taught and slack, stressing the cleats and making it very hard for the towed boat to steer. Remember the towed boat only has steerage way if the line is taught (in general - the towed boat may be able to surf down a wave).

Only use a line astern for a long tow out at sea or in fairly open water. If you are going to be manoeuvring the boat at all or bringing her into a berth then bring her alongside and do an alongside tow. Have a quick read up on how to do that as it's not difficult but placing the lines right will give you much better steerage.

If the boat you want to tow has lost her steerage or worse, her rudder, expect it to be very difficult to tow her at all if you can't get her alongside (frankly you should just call the coastguard/RNLI immediately if she's in any danger). You can stabilise things a bit by using a drogue trailed from the towed boat sometimes (I'm told this can help even if the towed boat has full steerage). And if you're towing a boat with a centreboard or similar and/or a lifting rudder then make sure she has them fully down.

 

[onesea]

The same goes for the towed boat. If the line is fixed at the bow, the towed boat will not be able to steer.

I am always amazed when I see peeps put a towline onto their bow cleat with a bowline, which cannot be undone or lifted off a cleat under strain. They have completely surrendered control of their vessel to the towing vessel. The only way they can bail out of the process would be to cut the line.

+1 Either party should be able to safely release the tow... under load....
You do not know what the other boat is going to do...

One other thing to remember (which seems pretty obvious but I've seen people forget it) is just how effective your rudder is (or isn't) at towing speeds. Outdrives and outboards are okay, displacement mobos and most sailing yachts generally too, but a planing boat on shafts doesn't always have the rudder authority to overcome the towed boats influence or to control the tow as the towed boat very well. There are one or two yachts that are not so good either as they have a massive inbuilt directional stability and not such a good turning circle, especially some older long keel or Keel and skeg designs - crabbing cross-tide with that sort of boat as the towed boat can be entertaining, especially if the tow is right from the bow (I used to work in the yards in BoC as a teenager as well as on the club launches so spent a fair bit of time towing).

The basic idea is that your tow becomes your rudder... It will pull you round if they are big enough. The whole logistics change when there is a boat behind that's why you tow on a bridal or even better a tow point forward of your rudder/ engines. Then you control the angle of the tow rope (using your rudders, or even by hand on one boat I was on) and it steers you!

Couple of things I haven't seen mentioned. Don't just use the full length of the line automatically - especially in a swell. The idea is to adjust the length of the line so that both boats ride up the front of the swell and then back down the other side at the time - otherwise you can end up with the tug climbing slowing up the wave while the towed boat is surfing down the back at the same time. It's not so much the danger of the two boats colliding as that the line goes alternately taught and slack, stressing the cleats and making it very hard for the towed boat to steer. Remember the towed boat only has steerage way if the line is taught (in general - the towed boat may be able to surf down a wave).

I would suggest that if in doubt longer is better but do try and time it as suggested. Also insert some chain or a heavy ish weight in the system, if you can keep the tow rope in the water, this will remove most of the shock loadings...

The towed boat will have steerage as long as its moving, but only when taught will it being pulled towards you. If it is unmanned they can sail where they want between snatches!

So try and avoid snatches constant force...

Only use a line astern for a long tow out at sea or in fairly open water. If you are going to be manoeuvring the boat at all or bringing her into a berth then bring her alongside and do an alongside tow. Have a quick read up on how to do that as it's not difficult but placing the lines right will give you much better steerage.

As a general rule the art is to try and make the tow vessel a push vessel by placing her as far aft as possible.

If the boat you want to tow has lost her steerage or worse, her rudder, expect it to be very difficult to tow her at all if you can't get her alongside (frankly you should just call the coastguard/RNLI immediately if she's in any danger). You can stabilise things a bit by using a drogue trailed from the towed boat sometimes (I'm told this can help even if the towed boat has full steerage).

With any boat with loss of steerage or not slowly increase the weight on the tow. If she is towing off to one side do not worry if you are making reasonable speed, Very few tows follow directly behind you.

Just try and avoid shock loading or it surging from side to side. Try using the Autopilot it might do a better job than you!

Depending on the failures you can also consider towing the tow backwards, it may help.

And if you're towing a boat with a centreboard or similar and/or a lifting rudder then make sure she has them fully down.

Here I REALLY DISAGREE particularly dinghy's, they need to be fully up or they will surge around on them and eventually capsize.

 

[grumpy_o_g]

Here I REALLY DISAGREE particularly dinghy's, they need to be fully up or they will surge around on them and eventually capsize.

If the are not steered I agree but I always found that a dinghy with someone on the tiller was best towed with board and rudder down - in fact with two tows out in parallel it was essential as they had to steer away from each other. The tow was usually from the bow as well. You need to keep the speed well down too.

 

[onesea]

If the are not steered I agree but I always found that a dinghy with someone on the tiller was best towed with board and rudder down - in fact with two tows out in parallel it was essential as they had to steer away from each other. The tow was usually from the bow as well. You need to keep the speed well down too.

There times where its easier to agree to differ, I have found both both up easier. If I had manned tows I would watch there steering was being sensible .