Is an A-FRAME usefull??

[Manos]

Jelly a very good idea but as you said cost is forbiding it. God idea nevertheless

[tim griffin]

still think both are good and still like the pole idea , question is how many ribs go out at night and need these a frames when a pole will do , in the Case of Manos and his charter ribs i can see the sense of a light pole with cross trees
for mounting vhf ariel and gps ariel as his boats are probably tucked up in bed when the sun goes down, also if you made the base plate strong enough you would get more hieght for towing wakeboarders and the like , Sports boats open type do not use them, alot i guess is the rugged go anywhere 4x4 appeal of ribs and how they look, both do the job just depends on what you want.
regards Tim
www.griffmarineservices.co.uk

[Athol]

In S.Africa we did not refer to "A" frames as "A" frames but as "roll bars". This because most of our launching took place off the beach directly into the surf. This is a releatrively dangerous activety and the "roll - bar" was to protect the motors in the event of fliping the boat duting the launch. For this reason nav. lights where never mounted onto the a-frame.

[Marki]

I deliberately did not spec an A frame on my Scorpion - the only advantage if you don't have a radar is that it keeps the all round white light high and at the stern - most other places and it ruins your night vision. They do however make good climbing frames and good to tie up to.

[Louise]

Originally Posted by Marki

I deliberately did not spec an A frame on my Scorpion

What were your reasons for not wanting one, Mark?

the only advantage if you don't have a radar is that it keeps the all round white light high and at the stern

And, as has been mentioned earlier, it gives you a foot or two more height for your VHF aerial, which has to be a good reason IMHO.

[Manos]

Originally Posted by Athol

For this reason nav. lights where never mounted onto the a-frame.

Now I understand Cheers

Tim you know how Greeks do things better than the Greeks. As we see it this year there is no need for A-frames (roll-bars) on our boats. No one uses them at night and not very many people requested to have skis or knee boards either. So the next boats we will get will be with just a ski pole doubling as a flag pole and having on the top one all-round white (anchor light) and two all round reds. The boats are equipped with torches and handheld spot lights any way. None has been used so far.

[Jelly]

Manos
I was meaning that with my current state of finances and the fact I've already got a stern A frame I couldn't justify the cost of having one built.
It would be a different matter if it was a new build and I seem to remeber these one for sale in the bits and peices section.
Jelly

[Manos]

No argument Jelly. I agreed with you. The cost for making an SS frame in Greece with some kind of bimini on it is a lot and I certainly will not do it for the hired RIBs.

[Erin]

Yeah, and a couple of serious points as well in favour of A frames. If you've got radar you most certainly want it above your head... not good microwaving your brains (maybe not quite the right smilie but gives the right image!)

And the same applies to VHF. Weaker signal but still not healthy to stand directly in line with transmitting aerial.

[Marki]

Originally Posted by Louise

What were your reasons for not wanting one, Mark?
And, as has been mentioned earlier, it gives you a foot or two more height for your VHF aerial, which has to be a good reason IMHO.

I wanted a low profile - especially when on a trailer - I have a long aerial and have had no problems with range or reception.

[Justwin]

One point nobody seems to have touched on so far...

A decent twin tube S/S A Frame will act to stiffen the whole rear of the hull, in a similar manner to a strut brace in a performance car. When we ordered our boat from Tornado, specifying that we wanted the strongest (but lightest)configuration possible it was suggested that we have one fitted, also the reason that the fuel tank is under the console and not under deck. Plus on a boat with a narrow transom it gives a perfect place to mount the aux engine and fenders and fishing rods etc etc

And they look pants without them!

[Justwin]

Sorry, wrong sized attachments...

Try these

[Manos]

Marki just out of interest as the 1st time I hear this. Are VHF waves dangerous?? Can you expand on it please?


Justwin it is logical and it will stiffen the rear of a boat. Can you clarify this one plese? also the reason that the fuel tank is under the console and not under deck don't get it.

[Justwin]

No sorry, you're right. The fuel tank as you guessed has nothing to do with the stiffness of the rear of the boat, placing the fuel tank in the console (or anywhere else for that matter) as opposed to under the deck allows for stronger construction under deck.

Justin

[chrisallse]

(Quote) Marki just out of interest as the 1st time I hear this. Are VHF waves dangerous?? Can you expand on it please?




Only if the aerial pokes you in the eye

[Marki]

I have never been threatened by a vhf but assume if it is waving it's friendly

[Manos]

Originally Posted by chrisallse

Only if the aerial pokes you in the eye

Nice one

[Richard B]

Originally Posted by Justwin

A decent twin tube S/S A Frame will act to stiffen the whole rear of the hull, in a similar manner to a strut brace in a performance car.

Err... if you need a welded stainless steel structure to stiffen your RIB, then boy-o-boy have you got problems! Firstly, the transom and hull design should be adequate in the first place, and secondly, if the rear section of the hull does flex, it will crack the stainless steel around the welds where it's most brittle, and subject any any other stressed areas of the stainless steel to a "work hardening" effect which will make it more brittle and vulnerable to sudden failure (like the Comet airliners).

Sorry, mate, but it sounds like Lawrence Lock did a sales job on you to sell you an A-frame!

Originally Posted by Justwin

placing the fuel tank in the console (or anywhere else for that matter) as opposed to under the deck allows for stronger construction under deck

Why? This sounds like the salesman's words again! Decently designed box-section foam cored stringers should allow plenty of space for a tank and luggage space. Of course, if you splashed someone elses hull and just bodged the thing together with plywood inside, you might not feel confident about mounting a fuel tank inside...

All IMHO of course!

[Biggles]

'A' Frames look well hard.

RIBs just don't look like RIB's without them

[Manos]

Richard you are right but it also does make sence this stiffening of the aft of the boat by putting an A-frame.

Originally Posted by Justwin

placing the fuel tank in the console (or anywhere else for that matter) as opposed to under the deck allows for stronger construction under deck

I realy don't want to mention where I have heard that phrase before Justin. However, to Alan's delight I will give you a hint it was from the South side of the globe
THE SCORIPON (........for example - OK I know I'm going on and on about it but can't help it, is my new toy) has loads of space in the double bottoms and on top and on the side and everywhere and is bloody good and strong construction.