Entering a liferaft

[Tony Cross]

I can just read it...but I'll have to sit very close to the screen. Later, maybe!

Open the jpeg with a viewer that lets you zoom in (Picasa or IrfanView for example) and zoom in. I managed to read it fairly well that way. Most interesting too, and scary.

 

[Malo37]

Done the North Sea offshore survival course several times and from that experience I can say with some confidence that getting into a life raft from the water is not easy, in fact several people found it impossible. The strongest should board the life raft first and help pull the others in. A lot of the leisure type life rafts meet the bare minimum requirement only and are alarmingly small when inflated. The best ones are symmetrical ie it doesn't matter which way up they inflate. Ideally the objective should be to keep dry which obviously is unlikely to be achieved in heavy weather. Personally if doing a lot of offshore sailing I would invest in survival suits in addition to a good life raft. If you're over 50 you are likely so succumb to the effects of cold sea temperatures before you make it into the raft anyway.

 

[Malo37]

You need to fill a hell of a lot of volume with foam to provide positive buoyancy for a ballasted boat. 0.9 cubic metres per tonne of displacement.

Pedantic I know but actually 0.98 m3/tonne ( unless you're in the Dead Sea) so even worse just to achieve neutral buoyancy. You would then need to also add the positive buoyancy element on top of that. In short -not possible.

 

[Greenheart]

In short - not possible.

Isn't that putting it too shortly? Evidently it is possible, just seriously awkward. But no worse than spending your last freezing hours vainly struggling to climb into a liferaft.

View attachment 42429

 

[Tradewinds]

Don'View attachment 42425t know if this is going to work

This may be easier to read Patrick.

 

[Mad Pad]

Thanks Nigel,at least I was young and fit at the time!
The liferaft was an Avon from memory.
The wreck was picked up by a Russian frieghter and dumped on the quayside in Alexandria.
Got a few personal bits back,but some Egyptian is wearing my gold cufflinks?
Had been to a wedding in Cork so lost my top hat and tails...can't imagine those being worn there.
Thanks,
Mad Pad

 

[rogerthebodger]

I can recall an artical some years ago in PBO I think about a guy who used diver salvage inflatable bags and a SCUBA dive cylinder setup to provide emergency buoyancy in case his yacht was holed and sinking.

Don't how effective it was and how it worked in a real life emergency.

My Viking life raft has an inflatable boarding step to help getting into the life raft from the water

 

[AntarcticPilot]

On the subject of auxiliary buoyancy, how about "camels"? Two large inflatable cylinders, to be deployed on either side of the hull? They could be attached to the toerail, or to the chains and forestay/backstay fittings.

 

[fisherman]

I can recall an artical some years ago in PBO I think about a guy who used diver salvage inflatable bags and a SCUBA dive cylinder setup to provide emergency buoyancy in case his yacht was holed and sinking.

Thing about salvage bags is they are open like a parachute, so they can spill air as they rise and pressure falls, so might be difficult to keep inflated in a seaway, and would not keep a boat on the surface, designed to have the load hanging beneath them. You would have to attach them low down and all round. Better would be the sort of bag (closed sausage shape) the RNLI installed on some of the older lifeboats to self-right them. Not sure how well they worked under test.

 

[prv]

On the subject of auxiliary buoyancy, how about "camels"? Two large inflatable cylinders, to be deployed on either side of the hull? They could be attached to the toerail, or to the chains and forestay/backstay fittings.

Surely you'd end up with the deck several feet below the water? You have to have enough bag in the water to displace the weight of the boat, then the toe-rail hanging from the bottom of the bag...

Pete

 

[fisherman]

Surely you'd end up with the deck several feet below the water? You have to have enough bag in the water to displace the weight of the boat, then the toe-rail hanging from the bottom of the bag...

Pete

.....and will these fittings support the weight of the boat?

 

[prv]

.....and will these fittings support the weight of the boat?

Chainplates should.

Toerails aren't specifically designed to, but there's a lot of bolts through a strong piece of structure, so if a long bag was attached along a good length of aluminium toerail I can believe it would work.

Pete

 

[AntarcticPilot]

Surely you'd end up with the deck several feet below the water? You have to have enough bag in the water to displace the weight of the boat, then the toe-rail hanging from the bottom of the bag...

Pete

Perhaps straps or mesh between the two cylinders, running underneath the keel? If you could get straps in place, then ratchet tighteners would suffice to help the boat float a bit higher - we're not aiming for her to float on her marks, just to keep at worst awash. But I agree that there are engineering problems that would need resolving for it to be a viable solution; not least the problem of storing something that would probably be at least the size of a large inflatable!

As my reaction to a leak that wasn't going to sink her in minutes would be to try and get a sail under the hull and attempt to slow the inflow of water to where the pumps could cope (as Cook did off the Great Barrier Reef!), I could see all of this working as a coordinated "keep her afloat" strategy; inflated "camels" would give time for leak stiopping and pumping. And if far from land, I'd rather have the resources of the whole yacht - even if not navigable - available to help me survive, not just the limited resources of a life-raft.

 

[AntarcticPilot]

Chainplates should.

Toerails aren't specifically designed to, but there's a lot of bolts through a strong piece of structure, so if a long bag was attached along a good length of aluminium toerail I can believe it would work.

Pete

+1. My toe-rails take cleats that are certainly strong enough to take mooring loads; I think they are an integral part of the hull/deck structure. They are certainly bolted through at close intervals.

 

[Greenheart]

Not life-rafts...but a slightly different approach from enormous flotation bags: how about keeping a high-output petrol-powered pump for the day the boat is badly holed?

I was surprised how expensive they aren't. How many litres per hour could your electric bilge-pump shift if it really mattered? Maybe 4000?

View attachment 42648

This Honda weighs 21 kilos and is smaller than a mid-sized old-fashioned TV. It can shift upward of 30,000 litres per hour. Costs under £300 from these people: http://www.allpumpsdirect.co.uk/honda-wb20-petrol-engine-driven-water-pump

I suppose since it would be bought in optimistic expectation of never being used, it could be vacuum-packed in heavy plastic to prevent salt-air corrosion until required.

Did anyone mention water-tight doors? If a portion of the hull is breached beyond fothering or pumping capacity, it'd be a handy thing to be able to seal forecabin, aft cabin, etc.

Another expensive design-feature requiring inclusion during construction, and potential buyers happy to fork out in advance, anticipating the worst of all probable occurrences.

 

[prv]

Not life-rafts...but a slightly different approach from enormous flotation bags: how about keeping a high-output petrol-powered pump for the day the boat is badly holed?

Not unheard of among oceangoing yachts, I believe. Certainly the Mollymawks have one, fortunately so far only lent out to others rather than needed for mid-ocean survival themselves.

My fantasy ocean-voyaging design has space earmarked for a portable pump, together with one of the larger belt-driven Jabscos on the main engine and possibly a second one clutched from the generator engine.

Obviously even big pumps aren't going to allow you to ignore a substantial hole in the hull, but they would allow an improvised repair to leak a lot more and still be viable.

Pete

 

[Greenheart]

Does your fantasy-design feature watertight doors/compartments?

 

[prv]

Does your fantasy-design feature watertight doors/compartments?

The forepeak is a store / machinery space / mini workshop. All the best oceangoing boats have one; it's often integrated with the engine space aft. However, my layout doesn't allow for this, so in a nod to tradition, plus the fact that sleeping in the bow in a seaway is uncomfortable anyway, I put it up forward. The bulkhead between forepeak and accomodation is to be watertight; most of the time access would be through a traditional deck hatch (the kind with a coaming around it - I can't find a picture of exactly what I have in mind, but somewhere between http://www.luxe-motor-kei.co.uk/bbits/Images/bbits-031.jpg and http://www.sandemanyachtcompany.co.uk/uploads/386/12Foredeck.JPG ). However, there is also to be a small watertight access hatch from the accommodation. It's inevitably in one of the small "kids' cabins" and I'm sure the occupant would not appreciate it becoming a general thoroughfare

This is more in the nature of a collision bulkhead than watertight subdivision for buoyancy when holed. Intuitively I imagine the rest of the boat could stay afloat with the forepeak flooded, but not vice versa. The fantasy element doesn't extend to doing actual calculations

Pete

 

[Greenheart]

Like it! Especially the option to segregate children from the rest of the crew. Great way to guarantee good behaviour..."you'll end up in the chamber without a door!"

There must be good sense in making the bow-section separable from the rest of the hull - I wonder what proportion of ocean-going vessels have been sunk by holing in the forward 25% of the waterline length, as opposed to the rest of the hull?

I'm sure most vessels with flooded watertight forward compartments could stay afloat - not much point otherwise. Pretty sure I heard that if Captain Smith had steered Titanic straight into the berg, rather than trying to avoid it, the ship wouldn't have been lost. He'd have had to kill himself anyway though, bringing her into New York with a crumpled nose.

 

[prv]

There must be good sense in making the bow-section separable from the rest of the hull

I'm not certain, but I think it's standard in ships.

Certainly in Stavros, the whole focsle is separate from the rest of the hull below decks. There's a hatch on deck with a ladder down to the bosun's store, then down to further stores, the paint locker, the chain lockers, a little-used workbench, etc. The bulkhead aft of these compartments is unbroken except for wiring (and I imagine the opening is sealed around the wires) and the fire-main. This is one of several points on my design taking inspiration from Stavros and William.

Pete