"A" frames

[erico]

Can you tell me is there any other reason for " A " frames other than to place lights ,vhf etc. or is your rib not complete without it..!

ie Trendy...

[Alan]

A Frames on RIBS stem from the workboat/lifeboat begginnings of RIBS (e.g. Atlantic 21). Their purpose was not only for nav lights, antennae etc but more importantly for self righting gear - a bag which is inflated by means of compressed gas in order to right the RIB should it capsize. This has to be mounted above the deck level of the RIB to give sufficient righting "moment" to function correctly.

Few cruising RIBS have self righting gear - most of us don't intend to be out in that sort of extreme conditions!

A frames have evolved as a fashion item its true. They do serve a purpose for Nav lights, vhf/gps antennae, flags etc and to an extent make a RIB look "proper". The downside is that the weight of the A frame is in the place where it is least needed - i.e. the stern of the boat already burdened with an outboard (or inboard) engine! I suspect on some RIBS the A frame also provides some structural rigidity for the transom!

I've often thought some sort of "roll bar" over the helm console would be a better place for the flying antennae and nav lights. On consequence would be the boat would be a lot taller on its trailer which could be a problem I suppose.

HTH, Alan

[Bobaw]

I have recently moved my "A" Frame off the stern of the boat and placed it forward above the centre console.

As Alan quite rightly points out the frame is usually in the wrong place due to weight issues, and this is correct.

Having gone for a quick spin after doing the work, I managed a few more knots and the handling improved considerably at speed.

I thought it was going to be a big job, but with a bit of help it is possible to move it at little cost.

When I can afford a digi camera I will post photos of before and after....

[erico]

Thanks Bob

As I am about to get a new boat .. I would like to try and get it right to start with...does anyone else think that this might be the norm for new ribs...?

EricO

[jace]

Generally as you say, the ‘A’ frame is just there to look pretty and somewhere to put you navigation lights or Ariel’s.

Not personally experienced any disadvantages with the extra weight on the transom as long as you have the boat balanced correctly i.e. fuel lowest point possible and a good way forward.

[jools]

Or how about one of the Camel Ribs - with special frame!!

Even got space to carry your bike

[jools]

With attached bike!! - Must have been some sight!

[Jono Garton]

Andy


That guys got your dry suit on!!! second on the left !!!!


Did you get them ok?

[Andy.R]

Jono,
Yup, they were waiting for me in my room. Dry bag is pretty cool too. Cheers, for sending them. Just need to save for the Camel boat now, or at least the roof rack!!
Andy.
z

[Scubakid]

here is a pic of my A frame in the centre of the boat

John