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29 November 2011, 17:10
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#1
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Member
Country: UK - Channel Islands
Town: Jersey
Boat name: Jersey Seafaris
Make: Humber
Length: 8m +
Engine: 2 x 200hp evinrude
Join Date: Jun 2011
Posts: 10
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Liferaft on top of A frame?!
I have been thinking about putting my 14 man liferaft on top of my A frame on a 8.5 meter Humber rib.
It is early days and just a thought at the moment, the idea was freeing up some space for further seating/storage. At the moment the liferaft is just in front of a centre console. The liferaft is just as accessible if mounted on top of the A frame.
Has anyone tried this or seen this done before, some advice on the matter would be great!
Rich
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29 November 2011, 17:25
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#2
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RIBnet supporter
Country: UK - England
Town: Hants
Length: 8m +
Engine: 300hp plus
Join Date: Sep 2007
Posts: 3,072
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Hi we reviewed this position hanging beneath the top rail of the AFRame on an 8 metre but the overal consensus was the weight issue of a twelve man liferaft some 45kilos up high would change the balance of the RIB. We have seen numerous fittings with liferafts either side of the base of the A FRame just above the tube . Again a wet area and a lot of weight on the stern. I did fit a 6 man to the rear by the wash well area and even this proved to heavy and we had it moved by Biffer on the cradle to the bow area to gain balance back.
I would be looking at the manufacturer to give you weight figures for any loadings. We have found the best place for most of our liferafts to be forward of the consul helm position as all passengers are alongside and to the rear. I guess with a large rear helm the raft might have a good balance if all passengers are ahead of the consul position.
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29 November 2011, 17:42
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#3
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RIBnet admin team
Country: Ireland
Length: 4m +
Join Date: Feb 2008
Posts: 14,856
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Dr. Doof put his RADAR dome (5kg?) on his Humber A frame. The frame began to flex badly and it cracked.
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29 November 2011, 18:26
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#4
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RIBnet admin team
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: Tohatsu 30HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 11,626
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Google suggests a 14-man liferaft in a canister might weigh 60kg, so even assuming you have the a frame engineered to take that (and the resulting leverage) and the boat balance is fine with it - could you actually deploy it in the sort of seas where a liferaft might be your preferred option? - its sounds hard enough to lift 60 kg at head height never mind when being thrown around in rough seas. The only time I can really imagine stepping off a RIB onto a liferaft being a no brainer is if it is on fire. That's most likely to involve the engine(s) in which case the a-frame really doesn't sound like the ideal spot for it.
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29 November 2011, 19:11
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#5
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Member
Country: UK - Channel Islands
Town: Jersey
Boat name: Jersey Seafaris
Make: Humber
Length: 8m +
Engine: 2 x 200hp evinrude
Join Date: Jun 2011
Posts: 10
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Thanks for your response people.
Balancing of the boat were my initial worries. The Aframe will be made to accomodate the liferaft if put there. But the point of when using a raft in a rib from Polwart is a good one!
I'm swaying on somewhere else to put the liferaft!
Thanks
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29 November 2011, 20:47
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#6
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Member
Country: UK - England
Town: Sussex
Boat name: Aintree
Make: Redbay Stormforce
Length: 7m +
Engine: Twin 150's
Join Date: Jun 2009
Posts: 257
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I agree. Most a frames struggle with a radar on it in rough conditions. I think a 14 man liferaft would only last a few big landings.
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30 November 2011, 09:20
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#7
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Member
Country: UK - England
Town: West Sussex
Length: no boat
Join Date: Oct 2002
Posts: 3,872
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Liferafts should be stored away from the passengers but in an easy accessible place should there ever be a need to deploy them in anger. We found that it is best to have 2 x 8 man packed in flat GRP containers. Here you may have an extra service bill but an 8 man will be much easier to handle then a 14 man especially for a single person. We fitted such arrangement on SeaSafari 1 and even with this extra weight on the stern it made no difference to the performance of the rib.
Looking at the attached photo you can see that even with 14 persons on board and the two 8 man liferafts the tubes still do not touch the surface of the water.
The photo of the yellow rib (a Parker 1000 Baltic) shows a similar arrangement
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Andre
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30 November 2011, 12:51
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#8
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Member
Country: Other
Town: Rosas
Boat name: Conqueror
Make: Valiant
Length: 7m +
Engine: Outboard 150hp Merc
Join Date: Dec 2010
Posts: 549
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You get a degree of redundancy with 2 8 man rafts as well of course.
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05 December 2011, 18:53
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#9
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Member
Country: UK - England
Town: Up Norf
Make: Avon SR4,Tremlett 23
Length: 4m +
Engine: Yam 55, Volvo 200
Join Date: Apr 2007
Posts: 5,217
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Quote:
Originally Posted by willk
Dr. Doof put his RADAR dome (5kg?) on his Humber A frame. The frame began to flex badly and it cracked.
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I thought them Humber A frames vibrated more than an Ann Summers party full of middle aged women anyway..... and then self destruct.
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05 December 2011, 20:06
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#10
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Member
Country: UK - England
Town: Nr Faversham, Kent
Boat name: C Rider
Make: Avon
Length: 5m +
Engine: Yam 80
Join Date: Jan 2005
Posts: 513
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Quote:
Originally Posted by chewy
vibrated more than an Ann Summers party full of middle aged women anyway..... and then self destruct.
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Is that not called a crisis?
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Searider - The Best 5.4 x Far
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06 December 2011, 03:52
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#11
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Member
Country: UK - England
Town: Weymouth
Length: no boat
Join Date: Aug 2005
Posts: 247
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If you are building the a frame to suit, and setting aside the top weight issues, the next issue is the sheer size and weight of the raft canister. There fore could you design a quick release system that on pulling "a pin" release the raft over the stern and straight into the water. All this from maybe just above the outboards and under the a frame?
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I went alongside the carrier, I survived and didnt even get shot at!!!
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06 December 2011, 05:39
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#12
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Member
Country: UK - England
Town: Up Norf
Make: Avon SR4,Tremlett 23
Length: 4m +
Engine: Yam 55, Volvo 200
Join Date: Apr 2007
Posts: 5,217
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Quote:
Originally Posted by Swifty
Is that not called a crisis?
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If your A frame turns into a quivering wreck and falls to the floor then yes it would be, the middle aged women at a Ann Summers party may be a different matter....
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