Ruffles
Well-Known Member
I stand corrected /forums/images/graemlins/tongue.gif
Liferaft, Canister or Valise
- Thread starter Norman_E
- Start date
andy_wilson
Well-Known Member
No way!
All instructions, advice anecdotal or otherwise, and all training courses recommend deploying the raft manually, under full control, and stepping across into it as the mother ship leaves the surface.
That's the ideal world.
In the real world you could rip your keel off, explode or be run down in the dark, or fog or while the watch keeper nodded off, and sink before you realise what has happened. In the real world you could be miles (or maybe just yards) from land and need to dive into the water before you are overcome by heat or fumes. I realise that in the latter instance the raft may be consumed as the hull burns to the waterline.
However, if you don't have time to organise yourself and the crew and deploy the raft manually, a correctly installed hydrostatic release gives you a second chance of using the raft. If the raft is lashed down on deck, or below or in a locker, you will probably never see it again.
The release is organised so that on immersion to a set depth the main lashing is severed allowing the natural bouyancy of the raft package to ascend to the surface. There is a slim but real chance that this may snag, a canister is less likely than a valise (which can also be used with a release), but still possible, especially in the unlikely event that the yacht inverts and remains that way until the mast is stuck in the bottom.
As the yacht is sinking with the raft package now on the surface, the painter which is still attached to the weak link side of the release mechanism, is paying out until it reaches the point to deploy the raft. After this occurs, the bouyancy of the inflated raft is such that the painter breaks the weak link and separates from the sinking vessel. During this time, if the raft is the right way up, all of the water ballast pockets will be filling and drift will be much reduced.
Clearly however, at this point raft and crew need to come together quickly to prevent separation. Usually the raft will be surrounded by bits of string attaching all the accessories to prevent loss, and also the painter, rescue quiot and sea anchor may well be close to hand if the raft is floating away.
It is important to know where the knife is at this point, and understand why I do not favour life rafts at the rear of pitching boats with props / p-brackets / saildrive legs / spade rudders. There is enough going off at this point without finding that the rudder has threaded itself through the raft boarding ladder, or the sea anchor has snagged on your rope cutters.
I can think of only one hazard that a hydrostatic release could introduce. That is where for some reason all training and instructions are ignored and a chance to manually deploy the raft is passed over, leading to a reliance on the mechanism. The hazards then are:
a
ersonel in water when it may be avoided.
b:Hydrostatic release fails completely.
c:Raft snags and cannot surface to deploy, or deploys whilst entagled in rigging etc.
The only 2 downsides to using a release is
a:Cost (2-3% of cost of raft and cradle etc).
b:Failure to attach release and raft correctly.
There is only 1 upside. When all is lost but (hopefully) all crew are clear, but in the water, a few seconds later the raft may appear.
Priceless!
All instructions, advice anecdotal or otherwise, and all training courses recommend deploying the raft manually, under full control, and stepping across into it as the mother ship leaves the surface.
That's the ideal world.
In the real world you could rip your keel off, explode or be run down in the dark, or fog or while the watch keeper nodded off, and sink before you realise what has happened. In the real world you could be miles (or maybe just yards) from land and need to dive into the water before you are overcome by heat or fumes. I realise that in the latter instance the raft may be consumed as the hull burns to the waterline.
However, if you don't have time to organise yourself and the crew and deploy the raft manually, a correctly installed hydrostatic release gives you a second chance of using the raft. If the raft is lashed down on deck, or below or in a locker, you will probably never see it again.
The release is organised so that on immersion to a set depth the main lashing is severed allowing the natural bouyancy of the raft package to ascend to the surface. There is a slim but real chance that this may snag, a canister is less likely than a valise (which can also be used with a release), but still possible, especially in the unlikely event that the yacht inverts and remains that way until the mast is stuck in the bottom.
As the yacht is sinking with the raft package now on the surface, the painter which is still attached to the weak link side of the release mechanism, is paying out until it reaches the point to deploy the raft. After this occurs, the bouyancy of the inflated raft is such that the painter breaks the weak link and separates from the sinking vessel. During this time, if the raft is the right way up, all of the water ballast pockets will be filling and drift will be much reduced.
Clearly however, at this point raft and crew need to come together quickly to prevent separation. Usually the raft will be surrounded by bits of string attaching all the accessories to prevent loss, and also the painter, rescue quiot and sea anchor may well be close to hand if the raft is floating away.
It is important to know where the knife is at this point, and understand why I do not favour life rafts at the rear of pitching boats with props / p-brackets / saildrive legs / spade rudders. There is enough going off at this point without finding that the rudder has threaded itself through the raft boarding ladder, or the sea anchor has snagged on your rope cutters.
I can think of only one hazard that a hydrostatic release could introduce. That is where for some reason all training and instructions are ignored and a chance to manually deploy the raft is passed over, leading to a reliance on the mechanism. The hazards then are:
a
ersonel in water when it may be avoided.b:Hydrostatic release fails completely.
c:Raft snags and cannot surface to deploy, or deploys whilst entagled in rigging etc.
The only 2 downsides to using a release is
a:Cost (2-3% of cost of raft and cradle etc).
b:Failure to attach release and raft correctly.
There is only 1 upside. When all is lost but (hopefully) all crew are clear, but in the water, a few seconds later the raft may appear.
Priceless!
G
Guest
Guest
Re: No way!
Fair enough, I may have to consider getting one. I was rather put off in the shop when I heard it was set to 2m, which I reckoned, bearing in mind that things don't always work as they should, was a bit marginal and posed a risk of triggering while inverted. Alsoseem to remember reading an MAIB report of a fishing vessel where either the device failed or the raft was tangled.
But if they can be set to 4m or so I guess I was wrong to be concerned.
Fair enough, I may have to consider getting one. I was rather put off in the shop when I heard it was set to 2m, which I reckoned, bearing in mind that things don't always work as they should, was a bit marginal and posed a risk of triggering while inverted. Alsoseem to remember reading an MAIB report of a fishing vessel where either the device failed or the raft was tangled.
But if they can be set to 4m or so I guess I was wrong to be concerned.
Norman_E
Well-Known Member
Lots of food for thought here. Thanks to everyone. When I return to the boat I am going to measure the locker under the Starboard helmsman's seat. All it has in it is the shorepower cable. I think that could be partitioned off, and the rest of the space might make a snug home for a liferaft, which could easily be pulled out and deployed through the transom gates rather than lugging it over the rail.
Ships_Cat
Well-Known Member
Re: No way!
The only 2 downsides to using a release is
You missed out the raft blowing away.
When the release operates the boat will be, say, 4 m underwater. The raft canister will release and float to the surface but once the boat has sunk to that depth (ie lost buoyancy) it will be sinking fast and with a typical painter length of 10m the raft will likely inflate with no or little delay once it is at the surface (and maybe even before) and the painter separate.
So generally, there will be little or no time for crew in the water to swim to the canister tethered to the sinking boat, the raft will likely be inflated and free.
Am not decrying the use of hydrostatic releases, just repeating my previous comment that they are not the panacea that many claim when promoting them on these forums. As I said, is plenty of evidence here that crews have not made it into the liferaft after it has been automatically deployed - and I suspect it is stimulating to the mind to recover bodies in lifejackets and an empty liferaft.
Better learn to swim fast, perhaps?
My personal view (and it is only that) is the raft is best in a cockpit locker dedicated to the purpose or, if the raft is easily handled (say 4 man valise pack), in a locker inside the boat adjacent to the companionway - proviso, due to increased risk for race boat CAT 0, 1, 2 aged June 2001 on cannot be below and then only if less than 40kg.
John
The only 2 downsides to using a release is
You missed out the raft blowing away.
When the release operates the boat will be, say, 4 m underwater. The raft canister will release and float to the surface but once the boat has sunk to that depth (ie lost buoyancy) it will be sinking fast and with a typical painter length of 10m the raft will likely inflate with no or little delay once it is at the surface (and maybe even before) and the painter separate.
So generally, there will be little or no time for crew in the water to swim to the canister tethered to the sinking boat, the raft will likely be inflated and free.
Am not decrying the use of hydrostatic releases, just repeating my previous comment that they are not the panacea that many claim when promoting them on these forums. As I said, is plenty of evidence here that crews have not made it into the liferaft after it has been automatically deployed - and I suspect it is stimulating to the mind to recover bodies in lifejackets and an empty liferaft.
Better learn to swim fast, perhaps?
My personal view (and it is only that) is the raft is best in a cockpit locker dedicated to the purpose or, if the raft is easily handled (say 4 man valise pack), in a locker inside the boat adjacent to the companionway - proviso, due to increased risk for race boat CAT 0, 1, 2 aged June 2001 on cannot be below and then only if less than 40kg.
John