A Frame fixing

Rogue Wave · 27 November 2004, 19:18

Does anybody now how A frames are generally fixed to decks on new boats

Pete7 · 27 November 2004, 19:39

Why won't are you up to now ?

Pete

MeMe · 27 November 2004, 19:54

............how to suck eggs ? Only jokin mate

Errrr, don't ask me I just buy em already sucked

Daniel TD5 · 27 November 2004, 20:12

Quote:

Originally Posted by Rogue Wave

Does anybody now how A frames are generally fixed to decks on new boats

not that well in most cases if you want a job done well do it your self

most fix to the transom with bolts and the floor with self tapping screws don,t see how you would bolt them in to the floor unless your have access under the deck

mine was just bolted to the transom with 20mm washers to spread the load
they have now been replaced with 60mm washers and square plates

dan

swginn · 27 November 2004, 22:14

Mine is a double A-frame. The back legs are bolted through the transom and the front legs are bolted through the hull. You can see the exterior stainless plates and bolts when you get down underneath the boat. Makes the installation very strong/rigid and reinforces the transom-hull join also. I understand Ribcrafts frames are bolted like this also. If you want pictures just let me know.

Rogue Wave · 27 November 2004, 22:24

I do so wish that Ribcraft were fastened in the manner you described. But the one I have been using lately seems to be fastened in a very much different manner. I like the through deck fixing myself

swginn · 27 November 2004, 22:32

Sorry, I should correct myself so. Most Ribcrafts are done this way. DGR posted back along that his was and every Ribcraft that I've ever seen has been like this too. Thru deck sounds good but you're gonna need to cut a hatch to do that which leaves you with more problems, ie: waterproofing the hatch. As its at the transom this is where most water collects overnight, you'll have to pump out the water that has seeped through the hatch before you go out which is a bit of a pain.

Searider · 28 November 2004, 16:16

Hi Stuart,

Not the answer to your question but for others guidance the Avon method of fixing the transom tie bars to the floor is to fix a "Bighead" fastener through a piece of plywood and to then laminate that to the floor. That way you get almost a bolted connection without having to drill through the floor or hull.

A bighead is basically a stainless steel plate with a stud welded / fastened to it. These can then be embedded into a GRP structure.

The A frame on the Avon is bolted to the transom only, as is the one on the Scorpion.

The bighead route could work well on a Ribcraft as it should be relatively easy to match the finish on the floor?

DGR · 28 November 2004, 19:28

Swginn is right - my A-frame is bolted through the deck - but it is the honking great big 2" tubed double one - so the smaller ones might still be attached differently on other Ribcrafts.

Rogue Wave · 28 November 2004, 19:45

Ahh. I think i am talking at cross purposes to the rest of you. (that's never happenned before

) when people say through deck I envisaged a bolt going through the deck and into a plate shimilar to the Bighead plate Duncan mentionedl. The A frame I have the problem with is a double framed job on the back of a 7.8 and it was bolted through the deck using something similar to Rawlbolts

It think it might be going back on using a bighead plate!

Nickytynick · 28 November 2004, 19:46

Rogue,

I had my A-frame fabricated and fitted it myself.
It is a double 2" frame.

The back tube bolts directly through the transom utilising the existing U-bolts with a third bolt either side.

The front tube is bolted through the deck with 2xM10 bolts and nylock nuts either side. To gain access under the floor, I fitted 2x4" round inspection hatches just in board and toward the stern of the mounting point. They are completely watertight.
We use the frame to wakeboard so its pretty strong.

Suggest this is the way at least a double frame should be fitted or even better drill right through the floor and hull and plate on the outside. Didn't fancy this method personally but it would certainly be substantial!

Hope this helps...

Nick

DGR · 28 November 2004, 19:52

Rogue,

Ooops...mines a 7.8 - I assumed it had a plate in it!! All I can see from the outside is a hex bolt-head (which looks substantial) - I thought it would be more than a rawl-plug? How does that hold the a-frame? If it's the same as yours - how are you going to fix it?

Cheers,

Dylan...

Rogue Wave · 28 November 2004, 19:57

I think it might be going back on with the help of 2 4 inch inspection hatches. Pete 7 has some photos of the original fastenings and they were a surprise to me. Not as much as the A frame ripping off the back of the boat however!

Pete7 · 28 November 2004, 21:47

Seems the only thing in the deck is a sort of brass collett about 1cm across and 2 cm deep which that big bolt screws into. I am suprised I thought Ribcraft would do something more substantial than this. In addition because they didn't line the A frame legs up with the deck they had to put a wooden wedge in to take up the gap.

Pete

Nasher · 28 November 2004, 22:15

Stuart

Can't believe a manufacturer can get away with such poor design, I think the only way is to get the biggest backing plate under the deck and bolt through into it. The Inspection hatches sound like a good idea but will limit your backing plate to 4 inches in one direction, they are available in 6 inch which would be better, as would getting the nuts welded onto the backing plate to save hassle when fitting. It may also be worth cutting the ends off the A-frame and getting them welded back on at the right angle.
The wooden blocks are probably what caused the failure. They most likely soaked up water got soft and allowed an amount of movement that gradualy weakened the mounts.
If you need any help just shout.

Nasher.

By the way, I promise I'll get those kids life jackets back to you very soon.

Rogue Wave · 28 November 2004, 23:24

The offer of help is much appreciated and may well be accepted.!

The wooden wedges seemed to be the actual fixing point.

To be honest the failure wasn't caused by the weak fitting points It was caused by me doing something that caused the failure. However I am generally impressed with the strength of the Ribcraft and wasn't really having a go.

I have been in the shed making up some new blocks sand will epoxy themon tomorrow! I wont need the kida life jackets until the next season so keep em for the winter if they are going to get used

badbaws · 01 December 2004, 06:42

Who's boat is this for? Have you got yourself another one???
Well made it back from sea.. just.. Back alongside in Singapore..
How's Big Billy doing? and the storage idea?
Alex