transom strength for towing

[JABS]

This thread is out of control.

Stephen asked a theoretical question...

Could we revert to 'cutting a hole in a console' to take a tow rope!

[m chappelow]

Originally Posted by Rogue Wave

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!

HI R.W the boat poped out the tractor stayed put,thing is we have all types of boats from 13ft speed boats to yachts to 6 ton fishing cobles using the slip , the blue3 strand poly rope is not too bad and is much safer than nylon ,we were told to use polysteel rope by the insurance co ,its got no steel in it but goes dead if it parts ,

[BogMonster]

Originally Posted by prairie tuber

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.

That depends on whether you want something with a bit of "give" or something which will go bang tight and break something expensive. Anybody who has ever seen a 4x4 trying to "take a bit of a run to shift something" on the end of a dead tow rope, or worse a steel cable or chain, will know what I mean. There are plenty of stretched chassis around here to tell the story and all my on shore tow ropes are 24mm nylon

I would certainly say that anybody using nylon should be aware of the properties of it though, as has already been said it can catch the unwary completely by surprise.

I also have a mooring compensator similar to this

http://www.marinemegastore.com/produ...-PLA_16585.htm

which I bought and have never used so I think that might find its way into a tow line as it seems like it might be a good idea - I messed around with it when I got it and it does give a very progressive take up of the strain.

[Lugnut]

Originally Posted by BogMonster

Also just out of curiosity what sort of "bollard pull" (if I had a bollard!) would a typical 115hp outboard achieve? I guess it depends a lot on the prop pitch and revs achieved but I just wondered what a typical figure might be -

That's an interesting question. The fellows here might be able to answer that a bit better...

http://www.boatdesign.net/forums/

[codprawn]

Originally Posted by prairie tuber

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.

Polyprop WILL break your transom if there are any sudden snatch loads.

Try towing a car with a wire rope and you will know what I mean about snatch loads.

Climbing ropes are stretchy to absorb impact and stop the anchors ripping out.

Nylon rope is essential for towing in rough seas - put a weight in the middle and it will stop any sudden jerks if a fitting breaks.

This video clearly shows how much snatching occurs during towing.

http://www.youtube.com/watch?v=o2WtSPcGpKw

And to see a big mismatch in towing sizes

http://www.youtube.com/watch?v=CpulNiZH2RM

[hobbit555]

IF you are setting up a boat for towing, then placing to point a near to the centre of gravity will assist with manoverability, and stability of the towing vessel.
If you are worried about the strength of transom then either rope is to big or eye bolt is to thick. To me it is better to break either one of these than the transom. Apply power gradually but remember outboards are designed for top end speed as opposed grunt power, You dont need that much power to move a large vessel. Try leaning on a 70ft vessel along side a quay. it will move.
A few years ago there was a fishing boat that slowed a large tanker from running ashore near torquay during a gale. it held it for a while till a large tug arrived.

Choice of line to use depends on the job in hand, On tugs nylon/ polyprop mix is common as are nylons less so now days though. The important thing is not to exceed breaking strain, Frays and knots all weaken lines, Lots of line for towing astern for me

[hobbit555]

If the rope is snatching let more out

[spartacus]

Transom strength, rope material and how it is rigged up to one side for a minute.

Conditions on the day are crucial. This could have ended up far worse.

http://www.youtube.com/watch?v=aovFDywsNjk

[codprawn]

That looked nasty. They should have trailed some warps behind the boat being towed in those conditions.

[m chappelow]

Originally Posted by codprawn

That looked nasty. They should have trailed some warps behind the boat being towed in those conditions.

your right codprawn even on old car tyre would have done or a fender to act as a drogue we once had to tow a fishing boat back in in conditions nearly as bad and we used a lifering on the end also proves in the video why you need to tow with a long line apart from adusting to the swell and waves its saves the boat running into the back of the towing boat.

[Trickdog]

I don't think anyone has mentioned it but it's also good practice to have the tow rope set up to be a multiple of the wave length (minimum twice the wave length), so that the towing and towed boats are both riding the peaks and troughs of the waves at the same time. This helps to reduce snatching, together with a weight in the middle of the rope as Codprawn pointed out.

[floater]

I think in that last clip the main problem was then speed of the tow as the towed boat was almost planning.

Andy

[Rogue Wave]

Originally Posted by hobbit555

A few years ago there was a fishing boat that slowed a large tanker from running ashore near torquay during a gale. it held it for a while till a large tug arrived.

fkk me that's a nice salvage bill

[Bulligmore]

I don't think there is an issue with transom strength as we are only talking about from the engine to the tow eyes strength. The boat will not break of the transom as a result. A man died on Lough Erne last year when the metal cleat attached to one of the deck's flung back and killed him. I think it should be done with extreme care and slowly.


http://www.ireland.com/newspaper/bre...breaking37.htm

[Ian M]

Originally Posted by Bulligmore

I don't think there is an issue with transom strength as we are only talking about from the engine to the tow eyes strength. The boat will not break of the transom as a result. A man died on Lough Erne last year when the metal cleat attached to one of the deck's flung back and killed him. I think it should be done with extreme care and slowly.


http://www.ireland.com/newspaper/bre...breaking37.htm

Mmmm, lesson for me there I have taken ropes from grounded yachts and towed them off before now, withoout ever thinking about how they are fixed within the yacht.

[Rogue Wave]

Originally Posted by Rogue Wave

Nylon Rope banned why? Surely the ban should be on attaching to dodgy fittings

That was the point I was trying to make but not very well

I couldn't agree more with Buliggmores post His last point is well made