"New" Hazards appearing on the River Trent

[Naughty Cal]

No-ones asking you to pick if up.

 

The strain of towing a say 16 ton boat that is aground off a beach will come in at far more than 2.5 ton.

[phill]

Rubbish.

And that's 5 tonne

[Naughty Cal]

 

Its called being nice to people you dont know, and, helping those in a position you may find yourself in one day (when there isn't a tug available)

 

As the OP - I'd like to explain that we were in a flotilla, and if the two friends who came to assist had abandond me & gone merrily on their way, I wouldn't have been best pleased.

Why?

 

Were you in any imminent danger?

 

Was your life at risk?

 

Were you in danger of sinking?

 

You landed on the bloody beach, not them.

[phill]

Suggest you look up the difference between bollard pull and weight

[Alan de Enfield]

 

The strain of towing a say 16 ton boat that is aground off a beach will come in at far more than 2.5 ton.

 

You are making an assumption that it is totally out of the water when in fact probably 90% of the boats weight was supported by water

[Naughty Cal]

Rubbish.

And that's 5 tonne

No it isnt.

Suggest you look up the difference between bollard pull and weight

Like this bit?

 

"it is a convenient but idealized number that must be adjusted for operating conditions"

[Alan de Enfield]

Why?

 

Were you in any imminent danger?

 

Was your life at risk?

 

Were you in danger of sinking?

 

You landed on the bloody beach, not them.

 

You really do have a strange attitude to life.

[Naughty Cal]

 

You are making an assumption that it is totally out of the water when in fact probably 90% of the boats weight was supported by water

If its only 10% aground get the thing off the beach yourself.

 

You really do have a strange attitude to life.

No. I don't expect others I'm cruising with to put their boats at risk to "rescue" me from my cock up, especially when there is professional help at hand so close.

 

If one of your rescuers had damaged their boat helping you would you have paid for the damage?

[Alan de Enfield]

If its only 10% aground get the thing off the beach yourself.

 

You are having difficulties again today aren't you ?

 

10% by weight is about 1.5 tonnes, I would struggle to push that by myself.

[Naughty Cal]

Get the tug then from across the river. Its what its there for.

 

Better still don't cut corners on the river and get grounded

 

It isnt an unknown shoal.

[Puddlejumper]

That shoal has been there as long as we have had a boat, about seven years now.

 

Obviously with lower water levels it will be further out into the river!

Maggie told me that that shoal has been there as long as she can remember 50+ years and she should know born n raised in Farndon and when she was a kiddy a great treat was to go over on the Farndon ferry (Clarkys side) and spend hours paddling there, think it was a case of wrong time wrong place in the river and yes the Trent is very very low at the moment

[John V]

If Naughty Cal can produce 2.5 ton bollard pull I would not just be surprised....I'd be bloody amazed

[Naughty Cal]

It will be low. There has been very little in the way of rain of late.

If Naughty Cal can produce 2.5 ton bollard pull I would not just be surprised....I'd be bloody amazed

 

I suspect she would try and get airborne rather than exert force on the bollard

 

ETA: A "normal" harbour tug is rated at about 45 ton according to Google.

Edited September 16, 2014 by Naughty Cal

[John V]

Alongside by mudlarker2, on Flickr

 

Just to give some idea of scale this Tug the "Aicirtron" is rated at 10 ton bollard pull

063 by mudlarker2, on Flickr065 by mudlarker2, on Flickr

 

here are a couple of views of the engine room

[Naughty Cal]

It might need to wait for the tide before its doing much towing

[John V]

Incidentally it cruises with fenders down!!!

[Tony Dunkley]

If Naughty Cal can produce 2.5 ton bollard pull I would not just be surprised....I'd be bloody amazed

So would I . . . a well established "rule of thumb" for small conventional tugs with open propellors is around one ton of BP for every 100 Horsepower.

Edited September 16, 2014 by tony dunkley

[John V]

So would I . . . a well established "rule of thumb" for conventional tugs with open propellors is around one ton of BP for every 100 Horsepower.

 

and that's with a suitable prop to deliver that power whilst stationary !!!

[Tony Dunkley]

 

and that's with a suitable prop to deliver that power whilst stationary !!!

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.

[John V]

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.

 

 

Edited September 16, 2014 by John V

[Naughty Cal]

Its been called worse.

[Graham Davis]

Rubbish.

And that's 5 tonne

 

Why is it rubbish?

Any "object" that is aground has a greater resistance to the pull, therefore the load on the pull is greater than the weight of the "object". It is a fundamental rule we are taught in our (motorsport) Recovery training.

 

Or are you just being objectionable as usual?

[gazza]

It's much easier to pretend you can't help because your coastal rated cleats can't take any strain and then you can motor on past. ( probably waving cheerily at the same time to compound the feeling you generate in the stranded boat. )

 

Mind I am surprised that someone who bleats on about the Rules would so casually break the most important one.

You do spout some utter drivel.

[Tony Dunkley]

 

Why is it rubbish?

Any "object" that is aground has a greater resistance to the pull, therefore the load on the pull is greater than the weight of the "object". It is a fundamental rule we are taught in our (motorsport) Recovery training.

 

Or are you just being objectionable as usual?

The "load on the pull" as you call it is limited by the power of whatever is doing the pulling . . . the weight (displacement, if it's a boat) of whatever is being pulled makes no difference at all.

[Tony Dunkley]

It will be low. There has been very little in the way of rain of late.

 

I suspect she would try and get airborne rather than exert force on the bollard

 

ETA: A "normal" harbour tug is rated at about 45 ton according to Google.

 

 

 

The strain of towing a say 16 ton boat that is aground off a beach will come in at far more than 2.5 ton.

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.