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Old 19 June 2008, 07:49   #11
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Ta for the replies, all interesting stuff

Yes I agree that the scenario of a bit of metal heading towards me at speed is not welcome, I have seen the outcome of that using 24mm nylon rope snatch towing Land Rovers and it can be lethal and will take somebody's head off.

There aren't really any other boats round here to practice with reading the article just set me thinking about what I would do "if" something happened so I had some ideas in my head rather than standing there with a bundle of rope hopping from foot to foot thinking "ooh F where am I going to tie it on er um bugger b***ocks" while somebody drifted gracefully onto some rocks.

I can easily get 10mm and 24mm three strand nylon rope here so I was thinking about carrying maybe 30-50m of 10mm under the seat "just in case" - it isn't very expensive about 50p a metre I think. I have several 316 stainless shackles I bought last time I was in the UK so I think I might keep a "towing bag" kept stowed away somewhere with a bridle made up to spread the load between the eyes and a good long length of rope plus shackles, carabiners etc. not only for towing but in case the worst happens and I need a tow!

I don't want to spend time reinforcing the boat for something that may well never happen, really just wondering what the limits are of what is there. As JABS said the towing load should never really leave the transom, I wouldn't tow off the cleats as I have had enough problems with the blow up bits already one reason I replaced the ski hooks with eye bolts.

Thanks for the replies
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Old 19 June 2008, 08:01   #12
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I wouldn't worry too much about towing, anything large enough to break a boat will just leave you hanging by the rope going nowhere.
The power your outboard can produce will be less than that required to break the transom so its self limiting. The transom and motor are also all one unit so the rest of the hull is not being strained. The motor is pushing the transom which is pulling the load.
As far as pulling the bolts out is concerned this is how I have always recovered grapnels on ONE U bolt rather than tying across the two.
The grapnel hooked into the wreck is tied to a U bolt and once slack is taken up, to prevent shock loading, the motor is given some welly to bend the tines and pull the grapnel out of the wreck. For a moment the boat is straining on just about full power till it "pings" and I have never worried about popping the bolts out or seen any sign of it.
You don't need much power once something is moving and if you are heading towards WOT and it isn't moving then its too heavy
You can tow a suprising amount of boat with even quite a small RIB, just avoid shocks and jerks as this is what breaks things.
I don't keep a specific towing rig but would just use the 60m of 11mm anchor line if I needed to and tie rather than shackle onto the boat.
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Old 19 June 2008, 08:09   #13
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Originally Posted by JABS View Post
Maybe this is too simplbut consider:

The transom carries the engine. The 'push' comes from the engine.

Taking the load onto the transom is the best option becauce it doesn't go from boat to transom to engine?? So there is no extra force on the transom to hull joints??

Does that make sense.

I agree that a penny washer, provided it is thick enough not to bend will take a huge force.
I like simple, and that makes sense. Especially, if I try to pull a very large load, gradually appling power so there is no shock loading. But if my boat is moving and then the rope goes taught it effectively tries to stop the boat - the transom stays where it is whilst the inertia of the hull tries to rip the transom off?
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Old 19 June 2008, 08:24   #14
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its ok towing from the transom but when it comes to trying to steer its hard as the towing boat keeps getting straighted up if the towed boat is heaver or deeper in the water, a way around it is to have a bridle from the transom and then have a sliding ring or shackle to the tow line , if you are going to tow other than a straight line and you need to steer the best tow point is midships ,as another member said earlier the rnli atlantic ribs tow big stuff but they tow from a samson post in front of the roll bar and when setting a tow up they have to rig a bar over the engines to stop the tow rope getting caught on the cowls, another safety point is dont use nylon rope when recovering a boat or trailor with a vehicle on a slipway or beach i once saw a young teenager loose an eye from a fitting on a speed boat breaking out whilst been pulled off a beach after getting swamped with a 4x4 years ago, health and safety at our club banned nylon rope for out of water use on the slip after that.
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Old 19 June 2008, 09:06   #15
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Nylon Rope banned why? Surely the ban should be on attaching to dodgy fittings

Tow from midships - how you gonna do that without compromising your console etc. If the boat is set up for it fair enough but if it's not it's all gonna get a bit tricky.

One other thing if you want to have stering control when you are towing isn't the best way to do a sideways tow
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Old 19 June 2008, 10:22   #16
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Nylon Rope banned why? Surely the ban should be on attaching to dodgy fittings

Tow from midships - how you gonna do that without compromising your console etc. If the boat is set up for it fair enough but if it's not it's all gonna get a bit tricky.

One other thing if you want to have stering control when you are towing isn't the best way to do a sideways tow
Hi R.W , we the boat club were told to use poly rope for lowering or recovering boats or the type of rope that goes dead if it parts with no whipback,nylon stretches up to 50 % before parting its great for anchors ,another reason was we had a boat and trailor run over the end of the slip and bottomed out the wheels over the sill the tractor had hell of load on it ,when it did pop out the whole lot shot up the slip , anyone in its way would have been killed ,granted the rope was long as to keep the tractor off the weed , and yes if towing in confined space its best to lash alongside to the other vessel.
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Old 19 June 2008, 10:33   #17
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Use a tow bridle - it means you still have steerage regardless of the angle of the tow, and it also shares the load between 4 fixing points!

Snatching is solved by a weight on the tow line - I have an olde rusty shackle off the QE2's anchor (slight exaggeration, but it's around the 1Kg mark) which if put on the tow line with a retaining / recovery string reduces the snatch a lot. Ironically the stretch of Nylon 3- strand which is good for absorbing shocks is the very same stretch that when the fitting fails will propel said fitting towards you at high speed!

As for towing yachts (from the beginning of the thread) I have moved an 8m with an Suz25 /SR4. Took a couple of mins to get going, but once on the move there was no easy stopping it! Bruce is abolutely right. Weight is slightly irrelevant when it comes to shifting through water at low speed - think of the umpteen tons of coal towed by one horse along a canal 200 years ago........
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Old 19 June 2008, 10:48   #18
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One other thing if you want to have stering control when you are towing isn't the best way to do a sideways tow
Actually, it's easier to steer both vessels with a sideways tow than a trailing tow. You ideally want the towed vessel's stern ahead of the midpoint of the towing vessel (i.e. thrust and steering well back of the towed vessel.)

You still get some steering offset from increased drag and asymmetrical mass, but not as much as you'd think.


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Old 19 June 2008, 10:54   #19
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Nylon rope is a huge no-no for any sort of towing or recovery - just as it is never to be used as a waterskiing rope. Use polyproplene or polyethylene rope.
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Old 19 June 2008, 11:14   #20
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It's possible I may be thining of the wong stuff when I call something Nylon rope I mean the blue 3 strand polyprop rope. I don't see much give in that and I certainly don't have a problem towing with that!

To go back to the tractor and trailer freefalling down the slipway to go subse a submarine state then reentering the atmosphere like a leviathon from the deep then I hope the launchee was banned along with the nylon rope. It strikes me as a case of very bad practice that the rope wasn't set up to be controlled properly. Must have been funny after the fact though!
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