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Old 06 March 2012, 18:45   #21
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Originally Posted by captnjack View Post
The swimmer loads them in the rescue litter one at a time. The whole reason they deploy into the water is because the victim is probably hypothermic and can't get in themselves. If you read the "history" link I posted towards the beginning there's 1980s a case study of the loss of numerous lives because they couldn't get into the litter. That vessel was far offshore in horrible conditions for another boat to pick up survivors.
I don't think we routinely use "litters" or baskets here.
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Does the Shannon lifeboat always launch from the beach? If so why not just build a launch ramp vs maintain the hydraulics and tracks etc of that trolly? I'm just guessing the tractor doesn't drive very far or very fast.
They are replacing the mersey class which are launched from tractors, down slipways and kept afloat - so it has to do all three. I have always understood they used tractors across the beach when the tidal range and distance involved (shallow beaches) was so big that building a launch slip wasn't practical. But others probably know better. Not sure what speed these tractors will have - but typically the launch tractors run at about 7 mph.
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Its a cool design but seems like a maintenance nightmare.
part of me likes to think they will have designed that out - but every station has a mechanic to look after the kit so it may not be as bad as if it were neglected like anyone else would!
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Oh and that old launch-retrieve system seems like it would be horrible with any kind of surf. Hard to tell since the videos are obviously sunny and calm
possibly - but stations that beach launch big boats have been doing so for years so either its not as bad as you think or they are all selected for sheltered beaches (and exposed stations use slipways or harbours) - or a bit of both.
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Old 06 March 2012, 19:18   #22
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Do you know the hull material? Hopefully not GRP... Maybe aluminum?

Any idea how those engines can be started in the almost dry and then get water to the jets while still partly on the trailer?

I'd love one, but more than 25knots please. lol My little RIB "only" does 29kn right now and don't fancy going slower!
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Old 06 March 2012, 19:46   #23
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Typical beach launch with the old Mersey class
,,only happens about 1 in every 70 launches when a prop picks up either a fall chain or winch rope from the carrage ,with the new shannon launcher this shouldent happen ,,,well it doesent have props

boat gets one of the fall chains from the trailer/carrage around the starboard prop causing it to come broadside to the surf ,coxn orders crew forward to lighten the stern and he then bulldozers it in reverse off the beach and well out past the surf,
this film was used as an example to train crews members how to react ,as it happend at Aldborough , so now ,if a coxn shouts were going to do an Aldborough they now know what hes going to do ,
------------------------------------------------------------------------
Engines on the new Shannon are 13 ltr scania and as i said earlier the SUPACAT Launcher /tractor has the same type engine so spare parts are compatable ,

one downside is that the basket/litter stretcher has to be now a 2 piece one as theres not enough room to store a full length one , if needed the casualty goes down the middle of the cabin tween the crew seats.

One other advantage is the mersey needs about 1.2 metres to float with the shannon having no props its around 0.75 metre, so can get into much shallower water .

HULL,S operational life expectancys now been upgraded from 25years to 55years though will be refitted out and re engined 3/4 times in that time ,
Hulls fibre composite and hull is made in 2 halves port /stbd ,,,glued together just like a model kit ,,
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Old 06 March 2012, 23:04   #24
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Oi seems to be awfully slow given a genuine severe weather emergency. Maybe your distances are shorter than ours once they get underway to make up response time.

Carbon fiber composite? Is there a skid plate on the bottom to protect the hull from all this beach scrapping and abuse?

Fascinating boat/program.
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Old 07 March 2012, 08:03   #25
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the dutch lifeboat KNRM has been a fan of jets (and big ribs) for years.
This is a little one, a valentine around 14metres.beach launching.

Loadsa vids on you-tube of these and the bigger Arie visser class (20metres,2x1k hp thru jets). Daughter was rnli crew here and then knrm crew when she worked in Holland for a few years as a jet boat skipper. She was on a "arie visser" class - the only brit and the only girlie on the boat. A development of the mountbatten class that was a joint knrm/rnli venture til the rnli decided it didnt want to go that way the bigger boat is an amazing bit of kit
Caister independent lifeboat has a valentine I believe.

Jets are great fun, we drive 'em nearly every day. Highly manoueverable when you get used to them. Stopping distance as in the rnli vid is sort of a boats length but do that with passengers onboard and they end up embedded in the woodwork..make a mess on the varnish.
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Old 07 March 2012, 08:11   #26
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The 'best' location for a lifeboat is moored alongside in a deep water berth - short response time, lowest cost, no restrictions on boat size and weight.

However for many locations around the UK and RoI this is not an option. In some locations the boat has to be moored off and accessed via a boarding boat (typically a SIB) which is not without risk. In one location (Workington) a Tyne class lifeboat is launched by crane. A boathouse with a slipway may be the best option, whilst as Polwart says above in some locations (eg those with a big tidal range) a tractor launched lifeboat is the only option - it is not without issues though:

Boathouse

Lifeboats are generally located so that they launch at locations protected from the prevailing conditions. Backup plans are in place if there is a risk that it may become impossible to launch or recover. As boats and equipment become more capable this is less of an issue (eg Shannon can recover onto the beach at speed and then load onto the trailer above the surf line, the extra power and bow thruster of the Tamar enable slipway recovery in conditions that would have been more challenging in a Tyne), however there may still be rare occasions when the boat will have to relocate with crew in advance of bad weather coming in, or stay in a local secondary location until recovery to the boathouse is possible.

Slipway and beach launched all weather lifeboats rely on the cooling water in the engines to keep the engines cool until the (self priming) sea water pump inlets are submerged. I'm not sure about the exact time limits, but they will run quite happily for minutes like this.

RNLI boats have a declared operational range out to 100 miles offshore. In calm weather, 25 knots is relatively slow, however as conditions worsen the lifeboat semi displacement hull design comes into its own as it can maintain more of the speed than a planing hull boat that is faster in calm conditions. The previous experimental FCB2 hull design was based on a successful commercial design and was good for 30 knots+ in calm conditions but was much slower in bad conditions due to the slamming loads on the crew.

Cheers

Chris
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Old 07 March 2012, 08:12   #27
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can see the jets on here....


and the katwijk boat beaching
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Old 07 March 2012, 11:54   #28
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The whole utility of a lifeboat in this part of the world pretty much expired with capable rotary wing aircraft. In Washington State they beach launched up until the 1940s or maybe 50s in some cases but after that all our lifeboats pretty much ended up in museums. We don't really have protected beaches - those above don't look too bad at least. The bays where you could moor here are unsafe to exit during storm conditions due to the bar formed by sediment at the mouth so they never really had many lifeboat stations in them. The US Coast Guard in this district is the only one with the authority to prohibit you exiting those bays in severe weather. No other district can actually say "you can't leave the harbor today" and enforce it. Those factors combined with the increased range and speed of today's helicopters means the remaining lifeboats here are less utilized for severe weather rescues than their design capabilities would suggest. We have some robust "lifeboats", although none are RIBs and I don't think any use jet power.

If you run out of fuel in a non-life threatening situation a commercial company will come sell you a few gallons to get home.
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Old 12 February 2014, 06:15   #29
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Great video - well worth the watch

Where's the steering wheel ?

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Old 12 February 2014, 06:24   #30
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Rather them than me, the bow mounted camera looking aft had me queasy just watching it
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