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Old 04-06-2012, 19:17   #91
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Re: A Dingy as a Lifeboat/Life Raft

It's a thought provoking point about getting aboard, and one undoubted advantage of a liferaft is that you can jump into it from any height without injury to yourself from rigid seats, floors, transom etc. (and it's a better target).

Not so much of an advantage from a small, sinking vessel, (and not so good for subsequent entrants), but the whole question requires deep reflection and needs resolution.

If you're engineeing a lifeboat based on an inflatable dingy, I think it would be hard to do better than a wooden transom, well ahead of the end of the tubes. That way, boarding over it keeps you close to the centre of buoyancy, which puts the raft at less risk of overturning. Doable in good conditions, but remember you might be injured, or less than superbly athletic.

My preference would be to build a robust tubular metal arch (like a sailboat radar arch), hinged where it attaches to the transom, which can serve as the canopy support and doorway once everyone's on board, but hinge down 180 degrees as a boarding step prior to that. PUT ANTISKID ON THE INSIDE FACE!

[The notion of a 'boarding platform', as previous posters have referred to in relation to liferafts, is intriguing. How do you attach a platform - a platform a person could stand on - to a floppy ring? Presumably the platform is also floppy: I'd think it would have to be to pack into the canister]

Returning to my proposal: The canopy would perhaps slope directly down to the "foredeck" in storm conditions, helping to keep the windage reduced, and the "centre of area" aft, for better seakeeping.

To support a canopy, another essential step when converting an inflatable to a lifeboat is to vulcanise a strip of heavy hypalon along the top of each pontoon, ("half-on, half-off", ie twice as wide as the joint interface) with strong grommets at frequent intervals, for attaching the canopy.
Position the strip so the tension arrives at a tangent to the tube for less risk of peel separation.

The Traveller has strips like this, and it has a permanent hypalon foredeck with another strip with similar grommets along the aft edge, held up by a tubular arch). The whole approach works well, and even if it gets damaged you can generally make it good.

A major advantage of a lifeboat over a liferaft is that you can reconfigure it to suit the conditions and your situation: the concept of a liferaft is predicated on the occupants being non-sailors, so most of the important choices are predetermined compromises.
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Old 04-06-2012, 19:18   #92
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Re: A Dingy as a Lifeboat/Life Raft

Proximity to a safe harbor is a safety benefit in the context of the storms I'm talking about. NOBODY would be out in some of what I've seen unless they were a few days run time from the nearest harbor. Sure, stuff can happen very close to home. A through hull could give way as you try to leave the harbor! But the line that separates the viability of an open dinghy as a survival craft, versus some life raft or lifeboat, is usually avoidable if you can get home within hours.
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Old 04-06-2012, 20:01   #93
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Re: A Dingy as a Lifeboat/Life Raft

I agree broadly with your conclusion, so what follows is clarification of my thoughts rather than disagreement with your post.

Proximity to a safe harbour is different from proximity to land, which is what I was talking about. The latter is what concerns me, but the distinction between the two, and the firmness of purpose to act on the distinction, is a test of both character and experience.

But there's another aspect: what constitutes a safe harbour?

I live in a place with several stretches of coastline many hundreds of miles long, and lots of shorter stretches, which do not offer safe harbours as I define them in the context under discussion- they may be entirely safe if you're in them, and they were when you left them, but they're not safe to approach in bad onshore conditions in a keel yacht- in some cases, you don't want to be anywhere near these coastal stretches in such conditions.

And, as luck would have it, the bad blows are generally onshore in these stretches.

The nearest I've ever come to an abandon ship situation (eg wearing a knife around my kneck) was about half an hour from a harbour so safe and commodious that oil exploration rigs used it to winter over.

And that harbour was under our lee.

And we were fighting for our lives to keep it that way.
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Old 04-06-2012, 23:40   #94
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Re: A Dingy as a Lifeboat/Life Raft

Just now listening to Gavin Brady (local boy) from "Beau Geste", en route to New Caledonia (in an ocean race) talking about a little problem they'd literally tripped over in the night (a crack across the deck, down the topsides, disappearing underwater towards the keel, and going clear through the core to the interior)

Gavin was having to wrestle with the question of whether to abandon:
"do we stay or do we go".

He put in a call to Bruce Farr. (There have been a few structural problems in the boat's relatively brief history, so Bruce was freshly across the scantlings and loads)
Bruce said "Get off the boat".

Easy for him to make that call, you might say(although professionally speaking, perhaps not)

It was blowing, not a lot, but a fair bit (50 knots), and conditions were such that Gavin was not sure liferafts were a better option.

He decided to try and nurse the boat to the Norfolk Islands, and they arrived not long ago, where they're still afloat, and in relative shelter.

These are NEVER easy decisions. I guess though that by staying with the boat they were still keeping the abandon option open, whereas once you leave, you're committed to "dance with the one you brung".

They were concerned at how quickly the boat would sink.

I guess this is a different order of magnitude in a modern racing hull than any cruising yacht remember One Australia's masthead disappearing beneath the waves in 1m30 in AmCup 95? Gavin certainly remembers ... he said so.

That's not long to get life rafts launched for 18 people, and get those people and rafts clear away, especially at night. Even if they are all on deck, kitted up and briefed and ready to go.

Probably doable, though, given that they're disciplined, experienced, well led, and fit.
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Old 05-06-2012, 00:22   #95
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Re: A Dingy as a Lifeboat/Life Raft

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Originally Posted by Andrew Troup View Post
remember One Australia's masthead disappearing beneath the waves in 1m30 in AmCup 95?
Several tonne of lead tends to do that to boats

I am still amazed that someone has not come up with quick release pins for ditching the mast and explosive bolts for the keel losing the majority of the weight but leaving enough for the vessel to remain relatively stable and reducing the enormous stresses to the hull from lugging that weight around ..

Of course some of us just have boats that are positively buoyant regardless of what happens
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Old 05-06-2012, 01:51   #96
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Re: A Dingy as a Lifeboat/Life Raft

Here is a link

Yacht rescued off Norfolk Island Australia
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Old 05-06-2012, 03:11   #97
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Re: A Dingy as a Lifeboat/Life Raft

Hey anyone here with actual experience of a situation where there was choice of dingy or life raft (not specially made rigid lifeboat) if so I would be pleased to read your comments
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Old 05-06-2012, 04:08   #98
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Re: A Dingy as a Lifeboat/Life Raft

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Originally Posted by Jbaffoh View Post
Maybe some storms are just not survivable if the mothership goes down.
I think that is very true.

FWIW, me Father used to have a 27 foot sailing boat (actually more of a motorsailor) that was built on the hull from a cruise liner's lifeboat (was a cancelled order back in the 60's). Classic ships lifeboat shape (double ender, a rudder the size of a barndoor and shallow draft - 2'6"!)...would sail at 6 knots, in a F5 - downhill .....with progress mostly sideways ............but under motor would go through anything (and "back in the day" we did get though all manner of sh#tty weather!). Rolled like a pig though! - but never enough where you thought she was never coming back .

IMO if you want a lifeboat - anything less is just wishful thinking, ......storage onboard might be a challenge though .
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Old 05-06-2012, 05:06   #99
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Re: A Dingy as a Lifeboat/Life Raft

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Originally Posted by David_Old_Jersey View Post
I think that is very true.

FWIW, me Father used to have a 27 foot sailing boat (actually more of a motorsailor) that was built on the hull from a cruise liner's lifeboat (was a cancelled order back in the 60's). Classic ships lifeboat shape (double ender, a rudder the size of a barndoor and shallow draft - 2'6"!)...would sail at 6 knots, in a F5 - downhill .....with progress mostly sideways ............but under motor would go through anything (and "back in the day" we did get though all manner of sh#tty weather!). Rolled like a pig though! - but never enough where you thought she was never coming back .

IMO if you want a lifeboat - anything less is just wishful thinking, ......storage onboard might be a challenge though .
Strap your 27 foot lifeboat to your 27 foot sail boat with a quick release mechanism and make a safe Cat. Then you wont have a storage problem. ( I am not serious just tongue in cheek) thank you for your very interesting reply. Anybody else out there want to contribute. Experience please!
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Old 05-06-2012, 13:07   #100
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Re: A Dingy as a Lifeboat/Life Raft

I forgot which book but I have read a true account of abandoning to a dinghy in a storm where they could not keep it upright and had to spend the night in the water under the dinghy hanging on to the straps so yes a dinghy has serious limitations in a real storm. I think that if I was in a situation where I had to abandon ship and had a good inflatable dinghy and a liferaft that I would bring the liferaft along with me in the dinghy. As far as being able to board an inflatable dinghy from the water, it is not all that easy but we do it all the time so are well practiced with the technique. If you were going to devise a survival kit for an inflatable tender it should have a small sea anchor, as well as some sort of boarding loop, canopy, strobe light, etc.. It does seem to me that a small sea anchor which could be deployed from the towing bridle on a RIB would solve a lot of the problems. A well designed survival kit attached to a ready to deploy good quality tender seems like a good option to me stiil, however, in some situations an emergency liferaft would be the only way to go but as I said before, you could have both
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Old 12-07-2012, 04:35   #101
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Re: A Dingy as a Lifeboat/Life Raft

Here's another experienced sailor who has reservations about liferafts

SetSail Blog Archive Dinghy Tent/Awning
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Old 12-07-2012, 12:44   #102
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Re: A Dingy as a Lifeboat/Life Raft

Interesting thread! Some photos for stimulating the little grey cells, some design cues for what is useful on a boat for surviving rough weather.

My boat is being designed with some of these features, and some from the Colin Archer design stable, and others. I plagiarise what works. The dinghy will be a whaler/wherry type, very similar to the boats below. Offshore, prepped as lifeboat with all the bells and whistles, ready for quick launch. It can tow the canister lifeboat if it's not too rough...they go over the rail together shortly before I step up.

Mind you, it would take a lot to sink the mothership...a bad rundown by a huge ship going fast, or a thorough hosedown from a heavy mg, for instance, but I'm hoping and planning to avoid those.

I could have sought out more, such as the surfboats the aussie lifesafers use (the wooden ones for rowing, not the RIBS). Lose the engine on the RIB and you lose its vital advantage, and without that you have the pleasure of rowing or sailing it. Yay.



The James Caird being launched from Elephant Island. Lovely sunny day on the beach....



This was the 800 mile short-hop cruise they made. Six man crew, beach rock ballast, no GPS, EPIRB, PFD, survival suit or watermaker, and they had a lovely afternoon stroll at the destination.



A modern replica. How about that, a lifeboat with a lifeboat. Now that's what I call belt & braces!

From link: James Caird replica Alexandra Shackleton is launched at Portland | intheboatshed.net



Under sail. Hmmm. I won't mention that the originals didn't choose a sloop rig for ease of handling or windward performance. Nope, I'll keep stum. Nobody will notice.

From link: Shackleton: James Caird Society News - expeditions



This trawler began life as a 1929 Coast Guard lifeboat, or as the owner describes, a "rollover lifeboat". Notice the hull lines, the reserve bouyancy for self righting. Notice the sugarscoop stern swim platform, and the cutaway transom for the outboard.

From link: Lifeboat Trawler



The Deal Lifeboat. Lovely overhangs. Plainly the fogeys knew nothing whatsoever about making a boat with the best chance of coming home safe. Was looking for some pics of the Deal Helicopter and C130, but couldn't find any. Wow, sailing must have been scary back then....



Another modern lifeboat. Notice the wooden boat in the background.

And a pdf about design and performance of the USCG 44 MLB. Some interesting info here:
http://www.uscg.mil/history/boats/docs/44footMLB.pdf
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Old 12-07-2012, 13:15   #103
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Re: A Dingy as a Lifeboat/Life Raft

Me Father had one of these:-



(the Wheel shelter is non-standard)

Based on a ships lifeboat hull - made out of hot moulded wood veneers. Under engine that would plough through anything (rolled a bit mind!).

Fairey Fisherman | Classic Boat Magazine

I have seen adverts for s/h (fibreglass) ships lifeboats that could be converted as above, maybe barge / leeboards would be the answer to 2' 6" of draft - and the progress under sail sideways that went with that. Plus maybe a bit more sail area.........
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Old 12-07-2012, 14:25   #104
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Re: A Dingy as a Lifeboat/Life Raft

Nice boat, and sounds like it sails the way it looks, but the guy at the helm also looks comfortable, and he is sailing and I am not.....yet.

The leeboard solution would be great....the Dutch have that kind of setup, on account of their shallow waters. Decent ballast, and not overloaded, and the setup is good. Won't win any races, and I bet they don't care....having too much fun.
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Old 28-07-2013, 08:21   #105
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Re: A Dingy as a Lifeboat/Life Raft

Rather than "dinghy as a lifeboat" you should think lifeboat/raft capable of sailing. Go and get George Sigler's book Experiment in Survival (at Amazon). The book shows that survival may depend on you being able to sail to safety. That's a problem with life rafts, they are made to stay in one location under the assumption that the rescue folks know where that location is. As an engineer, i can tell you that if something is going to go wrong, it will--like that battery in your EPIRB (You do have one, don't you?).

Anyway, I think you are on the right track--it is very important that you take an aggressive and proactive stance on emergency equipment. Just buying an expensive kit and hoping for the best someday will not tilt the odds of survival in your favor.
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