Hammar inflation triggers

[steve_cronin]

There was some discussion a year or two back on the pros & cons of varoius lifejacket release mechanisms.

I remember the pros 7 cons of chemical pellets and the pros of hammar but can anyone remind me of the "cons" of Hammar release?

Steve Cronin

 

[Roberto]

I remember this,
in case a hammar device equips a child lifejacket, there is the risk of it not opening because the water pressure may not be enough to trigger it..

 

[Mirelle]

Also, there has been an MCA circular about the risk of the Hammar inflators unscrewing themselves from the cylinders, over time. I believe that the design has been modified, but in any case it is a good habit to give it a quick twist to check it is screwed home before relying on it.

 

[Magic_Sailor]

I did some published tests on this unit used on a Crewsaver lifejacket.

I was concerned that during a sailing course I was on I jumped into a pool with all my gear on - oilies etc. The lifejacket did not inflate and I noticed that due to the large amount of air trapped in the oilies I was floating very close to the surface. I pulled the ripcord and it inflated with no probs.

I contacted crewsaver and they said that the mechanism needs to be under the water for about 4 seconds - they sent me a new one which I tested in my bath and it worked fine within that time.

This mechanism works by forcing water up a small tube hence the time delay. It is possible that I had not spent that amount of time in the water but I don't think so.

I have not had any other problems.

As a matter of safety, you should check that your compressed air cylinder is tightened onto the mechanism every time you use a self inflating lifejacket - regardless of make or type.

Magic

 

[whisper]

They are a lot more expensive than the "pellet" type so wouldn't bother with them for the family, just yourself.

 

[John_Clarke]

Use Loctite 222 on cylinders

I found that the cylinders in my Hammar inflation devices were loose so I contacted Crewsaver. Mr Kitchen of Crewsaver has told me that they now secure the gas bottles in their new lifejackets with Loctite 222 Threadlocker (this is the weakest of the Loctite products and is for screw threads rather than nuts or studs). When replacing the cylinder he advises applying a tiny drop to the end of the threads and it will be spread along the threads as the cylinder is screwed in. A 10 ml bottle cost about 6 UKP. Loctite UK can provide the name of a local stockist; they may have to order the 10 ml bottle.

 

[John_Clarke]

RNLI lifejackets

I have spoken to an RNLI safety advisor about lifejackets. The RNLI use Crewsaver because they are reliable and good quality. On the offshore boats they use the pellet type inflation devices because they are less expensive and easier to service than Hammar devices. The pellet type do need to be hung up in a ventilated area when not in use or they can auto-inflate if the humidity gets too high.

 

[RupertW]

Definitely worth checking the cylinder if you do have a Crewsaver. Mine failed to inflate on jumping into a swimming pool on a Sea Survival course and the instructor said that Crewsavers often failed because of cylinders working loose.

Crewsaver serviced the jacket for free for me - I hope they used Loctite!