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Idiot jet skis Southampton water

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Portsmouth harbour requires jetskis to have a license for the harbour.
They have to be data tagged and insured.
I saw four of them line abreast blasting into P/mouth taking up the whole harbour entrance . They seem to act with impunity.
 

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I've aslo noticed that the ones I've seen are usually riden by middle aged men not youngsters. They should know better.
 

BobnLesley

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... the ones I've seen are usually ridden by middle aged men not youngsters...
20 years ago now but a friend from Merseyside twice owned one over a three year period and was part of a 'club' which had something of a rolling membership. Once you'd totted-up enough points to lose your motorbike/car licence you bought a jet ski and played on that for the summer, then when you got your road licence back again, you sold-on the jet-ski to whomever had collected enough points to get a ban.
 

Never Grumble

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There's always been idiots around on fast moving craft. I still remember the day some years ago one cut across and had an engine failure immediately in front of us in the channel just south of the Hoe whilst exiting Plymouth. Rather stupid given we were a Leander class frigate, from the bridge wing I could hear the passengers screams, fortunately our skipper was a good ship handler and had his wits about him, not many would have gone full astern in that location and avoided a collision.
 

Rappey

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Didnt the leander class have a great party trick in that it could stop within its own length if needed?
A few years back a jetskier went between the hulls of a passenger catamaran, think it was around bristol channel ? He got well and truly prosecuted.
 

Scala

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...
Didnt the leander class have a great party trick in that it could stop within its own length if needed?
Be some strange physics if true.

Power is steam turbines, shafts and props. Displacement about 2600 tons. 110m long.

So at 28kts = 14.4 m/s it's covering its own length in about 7.6 seconds.

I can't see any marine propulsion system known to man, including the mythical caterpillar drive in Red Oktober, being able to stop 2800 tons in 7 seconds by reversing the thrust on some ancient props powered by steam turbines that take 2 minutes to spin down.

Sorry I think this is probably wrong... :)

Maybe if it hit a breakwater? Would work once I guess.
 
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Rappey

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Maybe it had variable pitch propellors so no need to decrease rpm ?
It was an article long ago.
I'm sure someone will know as I can't find anything relevant on google
 

East Cardinal

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There's always been idiots around on fast moving craft. I still remember the day some years ago one cut across and had an engine failure immediately in front of us in the channel just south of the Hoe whilst exiting Plymouth. Rather stupid given we were a Leander class frigate, from the bridge wing I could hear the passengers screams, fortunately our skipper was a good ship handler and had his wits about him, not many would have gone full astern in that location and avoided a collision.
Leander class Frigate.................lovely handling, much better than the later type 22 and 23
 

East Cardinal

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Be some strange physics if true.

Power is steam turbines, shafts and props. Displacement about 2600 tons. 110m long.

So at 28kts = 14.4 m/s it's covering its own length in about 7.6 seconds.

I can't see any marine propulsion system known to man, including the mythical caterpillar drive in Red Oktober, being able to stop 2800 tons in 7 seconds by reversing the thrust on some ancient props powered by steam turbines that take 2 minutes to spin down.

Sorry I think this is probably wrong... :)

Maybe if it hit a breakwater? Would work once I guess.

The Leander would not be doing 28 kn in the channel exiting Plymouth, more like 10 to 12 kn
The steam turbines do not take 2 minutes to run down. Even the gas turbines with reversing gearboxes
don't take more than 10 to 15 seconds from full ahead to full astern.
The steam supply feed into turbine is reversed and the reverse propulsion is available in a few seconds.
The problem they have is going from ahead to stop as the engineers have to get rid of steam
pressure and the build back up for drive again when needed.
Going from ahead immediately to astern uses the same steam but just fed into the turbine the other way,
and is much quicker to react.

Stopping in its own length would be possible from 10 kn or so but not at 28.
 

Bigplumbs

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More Jet Ski haters.... All have a right to use the water. Responsibly yes
 

Scala

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The Leander would not be doing 28 kn in the channel exiting Plymouth, more like 10 to 12 kn
The steam turbines do not take 2 minutes to run down. Even the gas turbines with reversing gearboxes
don't take more than 10 to 15 seconds from full ahead to full astern.
The steam supply feed into turbine is reversed and the reverse propulsion is available in a few seconds.
The problem they have is going from ahead to stop as the engineers have to get rid of steam
pressure and the build back up for drive again when needed.
Going from ahead immediately to astern uses the same steam but just fed into the turbine the other way,
and is much quicker to react.

Stopping in its own length would be possible from 10 kn or so but not at 28.
OK so maybe a bit of an exaggeration, but even at 10 kts I'm doubtful. That's 22 seconds. 0.6g.
But I'd be happy to be proved wrong :)
 

Never Grumble

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I much preferred my Leander steam to T22 gas turbine days. I don't know about the physics but we slowed enough not to hit it, allow it to restart its outboard and move on. And yes we'd have been doing 10knots or thereabouts, 28 would probably have put us into the speeding category and a telling off from QHM.
 

East Cardinal

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Scala,you are probably right (can't argue with physics), a ship length is a pretty quick. But I cant remember
it being a lot more. I only did a week navigation training on the Leander, before going to
navigate a type 42 destroyer. It would be safe to say if that same boat had
pulled across the bow of a 42, it may not have survived!!
 

Scala

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I much preferred my Leander steam to T22 gas turbine days. I don't know about the physics but we slowed enough not to hit it, allow it to restart its outboard and move on. And yes we'd have been doing 10knots or thereabouts, 28 would probably have put us into the speeding category and a telling off from QHM.
Scala,you are probably right (can't argue with physics), a ship length is a pretty quick. But I cant remember
it being a lot more. I only did a week navigation training on the Leander, before going to
navigate a type 42 destroyer. It would be safe to say if that same boat had
pulled across the bow of a 42, it may not have survived!!
That'd be some sight :)
 
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Bigplumbs

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I and I'm sure the overwhelming majority would agree with you, the key word though is 'responsibly'
And of course responsibly is subjective. I think Yachties sailing around zig zagging all over the place (I think they call it tacking) when they have a perfectly good engine they could use and go in a straight line is being irresponsible.

Tacking of course was used when boats did not have engines and had no other option.... Now there is another option some still like to tack all over the place and expect others to avoid them. Must be some sort of regression thing

So as I said Responsibly is subjective
 

Scala

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...
I think Yachties sailing around zig zagging all over the place (I think they call it tacking) when they have a perfectly good engine they could use and go in a straight line is being irresponsible.

Tacking of course was used when boats did not have engines and had no other option.... Now there is another option some still like to tack all over the place and expect others to avoid them. Must be some sort of regression thing
...
Are you for real?
 
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