Would you buy a second hand life raft?

[Refueler]

I think you missed the point. - there is a saying that one should get UP into a liferaft not Down into it.

Didn't miss the point as it read like you said we should wait for the release to work ....

Anyway - when I did survival course many years ago ... we were taught - first person jump onto the top of raft ... next people jump into the water as close to raft as possible ...

 

[greeny]

We service our own, as it is an important safety item and you need to be certain it is done correctly.

When we got our boat, the raft was marked as serviced and the seals on the container intact. The little card inside was nicely signed up and stamped etc. but the para flares and first aid kit that were signed off were missing. I've read other reports of people finding the deflation plugs missing from rafts etc, so my preference is to check it regularly ourselves, for exactly the same reason parachutists always pack their own chutes, it is simply too dangerous to leave the task to someone else.

I also would do my own servicing but unfortunately the authorities want to see certification of service by authorised competent service agency.
I guess you don't any authority breathing down you neck.

 

[[163233]]

I am well aware if how to deploy a Life Raft .....

I don't understand how it would get tangled in the kicking strap then?

 

[[163233]]

On our Sea Survival course, the instructor made exactly the same point; that an under-loaded raft is unstable...

They do say this, but the one I tried was surprisingly hard to flip with the pockets had filled with water.

 

[fisherman]

Couple of things I'd like to know, or suspect:
if the vessel capsizes and the raft is trapped in a float free cradle the HR may release but raft may not.
if the vessel capsizes and stays on the surface the HR may not fire.
If the vessel gets deep enough before the raft gets free there may not be enough buoyancy in the raft and canister for it to float, due to compression of air spaces.

We were advised on a FV where there is space to have the raft inflated on deck well before time to go. This would also have given me the chance to deal with my wrongly packed one above had I needed it.

 

[penberth3]

Couple of things I'd like to know, or suspect:
if the vessel capsizes and the raft is trapped in a float free cradle the HR may release but raft may not.
if the vessel capsizes and stays on the surface the HR may not fire.
If the vessel gets deep enough before the raft gets free there may not be enough buoyancy in the raft and canister for it to float, due to compression of air spaces.

We were advised on a FV where there is space to have the raft inflated on deck well before time to go. This would also have given me the chance to deal with my wrongly packed one above had I needed it.

I've seen this mentioned a few times in MAIB reports, where a raft set up to float clear if the vessel is sinking "straight down" has got snagged because the vessel is listed/capsized.

 

[Refueler]

Couple of things I'd like to know, or suspect:
if the vessel capsizes and the raft is trapped in a float free cradle the HR may release but raft may not.
if the vessel capsizes and stays on the surface the HR may not fire.
If the vessel gets deep enough before the raft gets free there may not be enough buoyancy in the raft and canister for it to float, due to compression of air spaces.

We were advised on a FV where there is space to have the raft inflated on deck well before time to go. This would also have given me the chance to deal with my wrongly packed one above had I needed it.

1. Possible
2. true
3. Not true.

As to inflating on deck first ? Personally - I prefer the inflate on the water ... to many items to interfere with the raft on a yacht etc.

 

[fisherman]

1. Possible
2. true
3. Not true.

As to inflating on deck first ? Personally - I prefer the inflate on the water ... to many items to interfere with the raft on a yacht etc.

(3) I'd like to discuss that point. At sufficient depth there must come a point where the air space buoyancy is less than the displacement of the uninflated raft, provided it is overall made of non buoyant materials. The neoprene will sink (??), as will the plastic canister and bottle,

 

[penberth3]

(3) I'd like to discuss that point. At sufficient depth there must come a point where the air space buoyancy is less than the displacement of the uninflated raft, provided it is overall made of non buoyant materials. The neoprene will sink (??), as will the plastic canister and bottle,

I guess there will be enough air in the unopened canister for it to float, even if water is leaking in and compressing the air. I think the biggest risks are the raft getting caught on something or the hydrostatic release not working.

 

[peterf]

My life raft canister has a small (15mm wide ish) plastic strap around the middle that keeps it closed. I guess its got a clever breaking strain design so that the inflation would break it and let the two parts of the canister separate and fall apart. If I was to open the liferaft to have a look/service, where would I get replacement for this white plastic strap?

 

[duncan99210]

I was wondering about packed life raft buoyancy and did the calculation of the volume of the raft and it’s weight. All the rafts I looked at well buoyant (ie their volume was say 50 litres, the weight was 28 kilos). I think the squashed air theory is false, as when you examine a packed raft there’s precious little free air space inside it. The raft itself is vacuum packed but is still buoyant. So if the raft is dragged down by a tangle or reluctant HR it’ll still float if it breaks free of its lashings.

 

[fisherman]

I was wondering about packed life raft buoyancy and did the calculation of the volume of the raft and it’s weight. All the rafts I looked at well buoyant (ie their volume was say 50 litres, the weight was 28 kilos). I think the squashed air theory is false, as when you examine a packed raft there’s precious little free air space inside it. The raft itself is vacuum packed but is still buoyant. So if the raft is dragged down by a tangle or reluctant HR it’ll still float if it breaks free of its lashings.

If it relies on trapped air spaces, then at some point pressure will do away with them, it's inevitable, question is how deep? Unless there is some pressure proof space and I can't see any except the bottle and that's no help. What else will float it?
All the same, it's an extreme circumstance, as the HR is set for about 1metre.

 

[duncan99210]

Most of the components of the raft are buoyant; the “trapped” air is not the key element that makes the raft float. The raft fabric is less dense than water, as are most of the bits of kit inside. So the packed raft will float well even if saturated with water. Nothing to do with trapped air, which is a bonus in terms of buoyancy.

 

[penberth3]

If it relies on trapped air spaces, then at some point pressure will do away with them, it's inevitable, question is how deep? Unless there is some pressure proof space and I can't see any except the bottle and that's no help. What else will float it?
All the same, it's an extreme circumstance, as the HR is set for about 1metre.

I haven't got time to think about the Gas Laws at the moment, but it's going to be 1000's of feet to compress free air to a tiny fraction of it's original volume.

 

[duncan99210]

I haven't got time to think about the Gas Laws at the moment, but it's going to be 1000's of feet to compress free air to a tiny fraction of it's original volume.

Pressure increases by 1 atmosphere per 10 metres. First 10 metres will reduce the gas volume to 1/2 of free volume, 20 metres will reduce to 1/3 of volume, 30 metres it will reduce to 1/4 of volume. And so on. Point is that it’s the first 10m that see the greatest loss of volume by compression.
But as I said above (#53) most of the materials in the raft are buoyant so it doesn’t rely on trapped air to make it float before inflation.

 

[fisherman]

I haven't got time to think about the Gas Laws at the moment, but it's going to be 1000's of feet to compress free air to a tiny fraction of it's original volume.

Yes. Put simply, I suppose 32ft deep =1 atm extra = half volume. The maximum depth I might sink in round here is 280ft, so reduction to about 12% of original volume, should be still good, even on the bottom.

 

[Refueler]

It does not matter about compressed air space .... simple archimedes ............

If the container is 50litres and weighs 28 kilos and sealed - it floats ... if dragged down it fight hard to regain surface.

Second - if the seal fails - as another says - the material and general makeup of the raft is buoyant material .... even the knife they give you floats ....

I have a sneaking suspicion that even the halves of the canister float ... but don't quote me on that .... I have two halves of a ships raft canister at home we use for cleaning / saving fish we catch ....

 

[Graham376]

I have a sneaking suspicion that even the halves of the canister float ... but don't quote me on that ....

It appears you are correct, at the end of the video, one half of the canister is just floating. We have the self righting 4 man version.

The Seasafe canister isn't sealed between the 2 sections and our previous Plastimo one had 4 holes with rope carry handles so, it seems the vacuum bag contents must have some buoyancy. There is an on-line underwater video of an auto deployment, simulating hru release but I can't find it now.

 

[Ruffles]

Ex hire are often available.

 

[Mud Lark]

I bought a secondhand Seago 4 man valise raft from eBay 10 years ago. Paid £200.
It was nearly due it's first service at three years. It's passed every inspection since and I'd say it's been a bargain compared to buying new or hiring.

Worth bearing in mind that at some point (I think 12 years?) the bottle needs to be pressure tested, which adds £100 to the service and also the battery for the light needs to be replaced, another£60 iirc.