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"New" Hazards appearing on the River Trent


Alan de Enfield

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That's right . . . the BP efficiency with a small diameter, high RPM propellor on a motorised soapdish like Naughty Cal's would be considerably less.

So it would compliment a poorly proportioned bath tub stuck in the wrong place quite well then?

 

 

 

The maximum bollard pull in tons, your boat could ever produce, is at best, your engine horsepower divided by 100.

 

So you would need 250 bhp plus to pull out or bust even one of your precious cleats.

So 170+bhp and an optimistic load rating on the deck furniture would make it fool hardy to consider rescuing a stuck tin tub with Rachel's boat.

 

See, we got there in the end.

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Actually IMO......no

 

Depending on how hard they were aground, which given the fairly low speed of canal craft wouldn't be very hard.

If it was aground towards the front then if the water tank was there, the first thing you would do is empty it

the second thing you would do is move everybody and every heavy loose object as far aft as possible

Then a quite light vessel with fairly limited power using a long tow and zig zagging while the vessel went astern would be quite likely to get it moving. it is surprising how little is needed to move something that appears stuck fast.

 

edit to add.....I have been on a tug with (from memory) less than 20 ton bollard pull, using a long wire hawser , snatch a 1,000 ton barge off a beach where it was aground

Edited by John V
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Don't forget its not the bollard pull that the prop can deliver, its how well the t stud/cleat is fixed to the boat.

 

A decent sized steel bollard or t stud will with stand a huge amount of force.

 

An aluminium cleat/stud fitted to a fiberglass superstructure with a pad spreading the load and a couple of M6 countersunk screws won't.

 

Regardless of how much grunt there is.

 

As you say though, it probably wouldn't have took much to shift it.

 

NC doesn't fancy getting into salvage and towing with her lovely boat, who can blame her.

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Don't forget its not the bollard pull that the prop can deliver, its how well the t stud/cleat is fixed to the boat.

 

A decent sized steel bollard or t stud will with stand a huge amount of force.

 

An aluminium cleat/stud fitted to a fiberglass superstructure with a pad spreading the load and a couple of M6 countersunk screws won't.

 

Regardless of how much grunt there is.

 

As you say though, it probably wouldn't have took much to shift it.

 

NC doesn't fancy getting into salvage and towing with her lovely boat, who can blame her.

 

 

Actually if you are aground like that and there is a very shallow draft boat around to act as a safety boat, it is amazing how much force a couple of guys in the water pushing at the bow can exert

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Who said we break any rules.

 

We help when it is safe to do so and wont cause damage or danger to our own vessel.

 

No rules broken.

 

If you had cleats rated at 2.5 tonnes strain would you tow a beached steel boat weighing much more with them?

My experience of grounding in a narrow boat is that it is not static bollard pull that gets you free, its the snatch when the rope goes taught and the momentum of the pulling boat is applied to the stuck boat. So whilst I would hope a reasonably heavy, but not necessarily powerful boat would help us get free, I would know that the likes of Naughty Cal, however willing, would probably not succeed. And so I might expect to receive their sympathy but also see them pass on by.

  • Greenie 1
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So it would compliment a poorly proportioned bath tub stuck in the wrong place quite well then?

 

So 170+bhp and an optimistic load rating on the deck furniture would make it fool hardy to consider rescuing a stuck tin tub with Rachel's boat.

 

See, we got there in the end.

Not if a bridle was rigged to share the load between two cleats . . . . as in Post 21.

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Not if a bridle was rigged to share the load between two cleats . . . . as in Post 21.

But as Rachel pointed out the foredeck and gunnels of her boat would make that an awkward procedure to carry out.

 

Leading us neatly back to one bow cleat not ideally suited to the job.....

 

Rachel, just to be clear, before you next take to the Trent, be sure to have a Samson post fitted to NC, you will be able to rescue inattentive boat crews in total confidence that she won't come to any harm.

Edited by gazza
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My experience of grounding in a narrow boat is that it is not static bollard pull that gets you free, its the snatch when the rope goes taught and the momentum of the pulling boat is applied to the stuck boat. So whilst I would hope a reasonably heavy, but not necessarily powerful boat would help us get free, I would know that the likes of Naughty Cal, however willing, would probably not succeed. And so I might expect to receive their sympathy but also see them pass on by.

True for mud, not so much for sand, gravel or marl.

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But as Rachel pointed out the foredeck and gunnels of her boat would make that an awkward procedure to carry out.

 

Leading us neatly back to one bow cleat not ideally suited to the job.....

 

Rachel, just to be clear, before you next take to the Trent, be sure to have a Samson post fitted to NC, you will be able to rescue inattentive boat crews in total confidence that she won't come to any harm.

 

Why? I think foredecks and gunwhales are fairly common features on boats . . . aren't they?

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Who said we break any rules.

 

We help when it is safe to do so and wont cause damage or danger to our own vessel.

 

No rules broken.

 

If you had cleats rated at 2.5 tonnes strain would you tow a beached steel boat weighing much more with them?

 

 

Please feel free to have a go at your method with NC if you think it will work.

 

You will most probably end up on the beach with the boat you are trying to assist.

 

In the case the OP is talking about why put your own boat in danger of grounding when there is a marina tug not 100 yards away who does the job day in day out?frusty.gif

NC post. An owner with great experience of this type, including a lot of lumpy work...

 

Why? I think foredecks and gunwhales are fairly common features on boats . . . aren't they?

See above.

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Good idea . . . when you've nothing worthwhile to say, keeping quiet is the best option.

My god, what a pompous answer!

 

There does seem to be something odd in you old buggers water on this forum lately

 

Have they changed your medication latley?

 

All your posts have added the square root of naff all to the discussion as to Naughty Cal's suitability as a tug boat.

 

The old adage applies nicely here.

 

Better to keep your mouth shut and be thought a fool then open it and confirm it.

 

Gaz out :-(

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Good idea . . . when you've nothing worthwhile to say, keeping quiet is the best option.

 

Tony

Are you being obtuse on purpose?

NC has a fibreglass boat that does not have the type of fittings you have mentioned. I'm sure you are fully aware of that matter.

 

Now I suppose I'll get a rude reply from you, as well.

Edited by Graham Davis
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Tony

Are you being obtuse on purpose?

NC has a fibreglass boat that does not have the type of fittings you have mentioned. I'm sure you are fully aware of that matter.

 

Now I suppose I'll get a rude reply from you, as well.

 

The only sort of fittings I've mentioned in connection with NC's boat are the cleats she's so worried about . . . so, no, I'm not being obtuse.

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Tony

Are you being obtuse on purpose?

NC has a fibreglass boat that does not have the type of fittings you have mentioned. I'm sure you are fully aware of that matter.

 

Now I suppose I'll get a rude reply from you, as well.

 

Sorry, but I can't see anything to be rude about.

Edited by tony dunkley
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If you had cleats rated at 2.5 tonnes strain would you tow a beached steel boat weighing much more with them?

 

 

 

 

 

Tony

Are you being obtuse on purpose?

NC has a fibreglass boat that does not have the type of fittings you have mentioned. I'm sure you are fully aware of that matter.

 

Now I suppose I'll get a rude reply from you, as well.

 

 

Graham....Tony is not being obtuse.....it all stems from NC's statement above which in both of our opinions is completely wrong

 

if (according to NC) the cleats are rated at 2.5 ton they would be totally safe because that is way above the bollard pull that Naughty Cal is capable of

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My god, what a pompous answer!

 

There does seem to be something odd in you old buggers water on this forum lately

 

Have they changed your medication latley?

 

All your posts have added the square root of naff all to the discussion as to Naughty Cal's suitability as a tug boat.

The old adage applies nicely here.

 

Better to keep your mouth shut and be thought a fool then open it and confirm it.

 

Gaz out :-(

 

I can fully understand why you say that . . . most of what I've said has clearly gone straight over the top of your head.

 

As far as the old adage goes , . . . that really is good advice, and I think you should take it.

  • Greenie 3
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Bollard pull is a very very specialist subject. (and also a matter of disagreement between designers)

 

She might be well acquainted with civil engineering and may well have a suitable background to understand the mathematics underpinning it. However that statement of hers shows she either was not thinking when she typed it or does not understand it's application.

Edited by John V
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Bollard pull is a very very specialist subject. (and also a matter of disagreement between designers)

 

She might be well acquainted with civil engineering and may well have a suitable background to understand the mathematics underpinning it. However that statement of hers shows she either was not thinking when she typed it or does not understand it's application.

 

Yes, it certainly is, and in it's common usage it is a practical and useful way of comparing or assessing towing capabilities.

Edited by tony dunkley
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