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Old 22 February 2007, 04:25   #1
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towing a rib safely

Does anyone here have any experience of towing a rib behind a larger boat?

The larger boat has two kleats either side of the stern,the rib has towing eyes facing seaward on the rib (I asked RC to put them there for this purpose) positioned 4ft back from the bow each side.

My concern is firstly loading, in relation to snatch, when both boats are out of sequence on waves, also the direction of pull if two fixed bridles are used.

Initally I thought (and still think ) climbing rope doubled up for stretch as the main line but thats as far as I've got, a rope bridle similar to the one used by skiers on the back of the transom is also an option but It think there will be a significant difference once again in loads, is there a larger capacity one out there ..?

Originally had a 4SR this was easy to tow,I tied the line to one side and raised the engine revs on the same side,everything tracked straight.

But this RC is a lot larger/heavier.

Any idea's would be appreciated.


Another one for you JW
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Old 22 February 2007, 04:54   #2
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You should not have a problem. Make a bridle between the two cleats on the larger vessel, then make a bowling in your tow line, or have a spliced eye made up with a stell ring in the cntre. This will ditribute the weight of the tow evenly and will prevent the tug from pulling to one side.

The attach the tow line to the bow eye which will be on the stem of the hull. This will be a strong point and will also prevent rubbing of the tow line on your sponsons. If you dont have a bow eye then make another bridle between the cleats which you refer to, and again attach the tow line to the bridle to spread the load.

With regards to snatch, make sure that the tow is as long as possible, and that the boat being towed is in the same wave trough as the boat towing. If you are getting snatch then you have attach some chain to the centre of the tow line, or even use a bucket.

May I also suggest that as you will not have any steerage on the towed vessel that you use a towing drogue that will be deployed from the stern.

Hope this helps

Simon
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Old 22 February 2007, 04:58   #3
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I would say that rigging a line on the “big boat” from one cleat to the other cleat with a block running in it, to which you could attach your climbing rope to this. Then copy this at the other end for the RIB, this should keep the pull strait and as much as possible keep the pull even on the points of each eye on the rib. And the longer the rope the more give it has.

Take it you are not talking of towing at a high speed
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Old 22 February 2007, 05:02   #4
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Quote:
Originally Posted by Simon Hawkins View Post
You should not have a problem. Make a bridle between the two cleats on the larger vessel, then make a bowling in your tow line, or have a spliced eye made up with a stell ring in the cntre. This will ditribute the weight of the tow evenly and will prevent the tug from pulling to one side.

The attach the tow line to the bow eye which will be on the stem of the hull. This will be a strong point and will also prevent rubbing of the tow line on your sponsons. If you dont have a bow eye then make another bridle between the cleats which you refer to, and again attach the tow line to the bridle to spread the load.

With regards to snatch, make sure that the tow is as long as possible, and that the boat being towed is in the same wave trough as the boat towing. If you are getting snatch then you have attach some chain to the centre of the tow line, or even use a bucket.

May I also suggest that as you will not have any steerage on the towed vessel that you use a towing drogue that will be deployed from the stern.

Hope this helps

Simon
Thanks simon,

The steel ring concept has answered most of the issues I had in relation to pull distribution. my only concern with something heavy enough to sink the rope at that point, is the possibilities of the rope getting round the prop of the larger boat.

Do you have a reason to attach to the bow eye on the rib? my searider used to steer/weave about when pulled from this location, RC suggested the rings positioned further back under the tubes may cure this...it's also a theory to ensure not losing the rib if towing at night when you can't see if it's still there.

Whats a bowling? and what do you think of the climbing rope idea?
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Old 22 February 2007, 05:05   #5
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Sorry I meant Bowline. Climbing rope is good as it is very strong.

Simon
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Old 22 February 2007, 05:14   #6
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Quote:
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I would say that rigging a line on the “big boat” from one cleat to the other cleat with a block running in it, to which you could attach your climbing rope to this. Then copy this at the other end for the RIB, this should keep the pull strait and as much as possible keep the pull even on the points of each eye on the rib. And the longer the rope the more give it has.

Take it you are not talking of towing at a high speed
Nope, no high speed stuff,

I've looked for blocks etc, the problem is the the size of rope I'm planning on using for the bridle 16mm the block would have to accomodate this and as yet I've not found one large enough to do it..
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Old 22 February 2007, 05:26   #7
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Waterski bridles have a float which usually has the pulley inside,
Adding a float like this would reduce risk of tangling the rope round prop on the tug.

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Thanks simon,

The steel ring concept has answered most of the issues I had in relation to pull distribution. my only concern with something heavy enough to sink the rope at that point, is the possibilities of the rope getting round the prop of the larger boat.
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Old 22 February 2007, 06:18   #8
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Nope, no high speed stuff,

I've looked for blocks etc, the problem is the the size of rope I'm planning on using for the bridle 16mm the block would have to accomodate this and as yet I've not found one large enough to do it..
Have you looked at snatch blocks?
e.g. http://en.lewmar.com/products/index....umber=19830500
They go past 16mm. Be prepared to loose an arm and leg though. It will cost around 70 squids.
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Old 22 February 2007, 06:24   #9
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Cleats aren't for towing, you need u bolts in the transom.
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Old 22 February 2007, 09:28   #10
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Have you looked at snatch blocks?
e.g. http://en.lewmar.com/products/index....umber=19830500
They go past 16mm. Be prepared to loose an arm and leg though. It will cost around 70 squids.
Minan gotten! 70 squids...... actually couldn't get your link to work, so googled ,the lewmar snatch block I did find for 16mm, was £300!.

So cheers, but the best option so far is still a S/S ring that can float along the bridle both big and small boat. I,m thinking about fitting a float at the ring to keep the bridle (BB end) up and out the way of the props.
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Old 22 February 2007, 09:34   #11
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Sorry I meant Bowline. Climbing rope is good as it is very strong.

Simon
Simon,

The climbing rope and S/S ring end....have you ever heard of climbing rope used in the way before; i'm a little dubious as to whether I could splice it to a large S/S hard eye which would be my preferred option. is this type of rope compatible with splicing?
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Old 22 February 2007, 10:26   #12
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Climbing rope is dreadful stuff, after a while the salt water will make it very stiff and difficult to handle. Diving club used to be given the stuff when the climbers no longer had any confidence in it. Also it doesn't have any give. Why not use some 10 - 12 mm 3 strand normal rope, a length of 40 metres on board will double up for lots of different uses including long mooring lines and it will splice.

Ensure the boat being towed is nose up, eg no one standing in the bow or it will tend to bow steer uncontrollably all over the place. Outboard down can give the towed boat some steerage, but exceed about 12 knots with the engine switched on and in gear and she will bump start

Pete
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Old 22 February 2007, 10:29   #13
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Also it doesn't have any give.


We used to use old climbing ropes to moor yachts up, for the simple reason that they were fairly springy and acted to some extent as shock absorbers...
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Old 22 February 2007, 10:32   #14
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towed this 7.5 Excalibur back (with a blown engine)from strumble to Cork at an average 22knots. SS carabina to a bridle on the tow rib with about 100' of rope between us. carabina was a bit mishapen in the end , but no other probs. driver of the towed boat said it was the best 5hr white water raft ride he'd ever had!

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Old 22 February 2007, 10:33   #15
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We used to use old climbing ropes to moor yachts up, for the simple reason that they were fairly springy and acted to some extent as shock absorbers...
Not compared to 10mm nylon, it really was horrible stiff stuff after it had dried out, we gave up on it as it wasn't easy to coil and handle.

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Old 22 February 2007, 10:35   #16
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or use one or more of the Rubber Mooring Compensator things on normal 3 ply line would provide it with some "give". but as suggested adding some form of float to the line close to the towing boat would prevent any rope to prop situations.
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Old 22 February 2007, 10:36   #17
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Climbing rope is dreadful stuff, after a while the salt water will make it very stiff and difficult to handle. Diving club used to be given the stuff when the climbers no longer had any confidence in it. Also it doesn't have any give. Why not use some 10 - 12 mm 3 strand normal rope, a length of 40 metres on board will double up for lots of different uses including long mooring lines and it will splice.

Ensure the boat being towed is nose up, eg no one standing in the bow or it will tend to bow steer uncontrollably all over the place. Outboard down can give the towed boat some steerage, but exceed about 12 knots with the engine switched on and in gear and she will bump start

Pete
Well that surprises me,the whole reason I was going down the climbing rope route was because the rope had give in it (so a falling climber dosen't get a broken back..) however it was an assumption I made.

The old rib did the all over the place steery thing (mainly when I forgot it was there and allowed the speed to climb) a,glance back to see the rib taking a fit, a loud "fork" and a dive for throttles.


the eyes under either side of the rib are supposed to stop that, the pull is from further back which should lift the bow...
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Old 22 February 2007, 10:55   #18
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The old rib did the all over the place steery thing (mainly when I forgot it was there and allowed the speed to climb) a,glance back to see the rib taking a fit, a loud "fork" and a dive for throttles. The eyes under either side of the rib are supposed to stop that, the pull is from further back which should lift the bow...
Towed Jimbos Tohatsu back from Cowes a couple of years ago at 15 knots. However the boat was empty (no one on board) , so nose light and it towed in a straight line. Towed another rib back from Rathlin but big heavy diver stood in the bow and caused her to bow steer. He was politely invited to move to the stern and the problem stopped. Final lesson we learnt was towing a 5.5m BMW along Portland Bill with Evinrude 115 engine and a flat battery. At 12 knots the cox could hear a "turbine" noise from the prop. He put it in gear and the boat slowed, back into neutral and up to 12 knots she bump started second time much to everyones astonishment.

Pete
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Old 22 February 2007, 11:02   #19
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Towed Jimbos Tohatsu back from Cowes a couple of years ago at 15 knots.
This was before it belonged to me
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Old 22 February 2007, 11:08   #20
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This was before it belonged to me
Yep, she tows really well and I was pleasantly suprised to get both boats up on the plane.
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