Avon Searider tube construction

Uglyrib · 21 February 2021, 17:41

Hi,
Excuse my ignorance but would somebody be willing to briefly explain the construction of the tubes on my early(unknown age) Avon Searider Sr4? There are two valves on port tube and one valve rear of starboard tube.Are there bladders inside the actual external tubes I e.three separate bladder chambers? What actually separates these 3 valves?
So I am actually asking in my honest to God ignorance because the starboard tube whilst being inflated made a rather large bang and the other side of the tubes inflated too!
Thing is she is now holding air really well but releasing any one of the valves and the whole thing goes flat!
Thanks,if anyone has the time for answering!

Pikey Dave · 21 February 2021, 17:59

Quote:

Originally Posted by Uglyrib

Hi,
Excuse my ignorance but would somebody be willing to briefly explain the construction of the tubes on my early(unknown age) Avon Searider Sr4? There are two valves on port tube and one valve rear of starboard tube.Are there bladders inside the actual external tubes I e.three separate bladder chambers? What actually separates these 3 valves?
So I am actually asking in my honest to God ignorance because the starboard tube whilst being inflated made a rather large bang and the other side of the tubes inflated too!
Thing is she is now holding air really well but releasing any one of the valves and the whole thing goes flat!
Thanks,if anyone has the time for answering!

You’ve blown a baffle. The tubes are separated by internal baffles. It sounds like one or both have failed.

oisin.higgins · 21 February 2021, 18:01

Every RIB I've come across has its tubes separated into chambers using baffles. I've never come across bladders within the chambers.

The baffles can fail over time: allowing air to go from one chamber to a neighbouring one. I suspect this was your loud bang, transferring air into the other chamber.

I assume that one of the Port valves is a lot closer to the bow than the other? If that's the case then the middle one would normally be for the bow chamber and the ones either side for the Port and Starboard chambers.

In short by the sounds of it, the baffles in your tubes have failed. As long as its holding pressure I wouldn't worry, however if you lose pressure on the water expect for them all to go flat.

Uglyrib · 21 February 2021, 18:21

Thank you for prompt replies.I can now say I am no longer baffled in every sense of the word!
I expect due to her age all baffled have now indeed gone.Thanks again for replies.

Orwell boy · 21 February 2021, 22:07

Athough your large bang sounds terminal under normal circumstances the seperating baffle is not a tight tube diameter circle ,when inflated if you could see it would appear more !/2 egg shape (in the tube ) so if you think about it it would depend which way you have pushed the egg shape as to how flat chambers either side would be if punctured ,so a non punctured chamber could appear punctured as the neighbouring chamber pushes the egg shape into a emptieing chamber
sorry i am now baffled

beamishken · 21 February 2021, 22:12

Quote:

Originally Posted by oisin.higgins

Every RIB I've come across has its tubes separated into chambers using baffles. I've never come across bladders within the chambers.

The baffles can fail over time: allowing air to go from one chamber to a neighbouring one. I suspect this was your loud bang, transferring air into the other chamber.

I assume that one of the Port valves is a lot closer to the bow than the other? If that's the case then the middle one would normally be for the bow chamber and the ones either side for the Port and Starboard chambers.

In short by the sounds of it, the baffles in your tubes have failed. As long as its holding pressure I wouldn't worry, however if you lose pressure on the water expect for them all to go flat.

Id definitely be worried about going any distance in a searider with all the baffles failed, that means zero residual bouyancy if you get one puncture, the idea of the baffles is if one chambers deflates then you can continue on with the remaining two, In the case of this boat one puncture and its going to sink like a stone

IainK · 22 February 2021, 10:30

Ignorance means a learning Monday - my 1988 SR6 Factory manual shows a construction detail and has a bit on repairing the baffles that appear to be fabric including the inserted cone - it may be the part that has blow through. The entire baffle may not have failed.
Best wishes and have a good week!
Iain

SimonCh · 22 February 2021, 11:12

Quote:

Originally Posted by Uglyrib

Hi,
Excuse my ignorance but would somebody be willing to briefly explain the construction of the tubes on my early(unknown age) Avon Searider Sr4? There are two valves on port tube and one valve rear of starboard tube.Are there bladders inside the actual external tubes I e.three separate bladder chambers? What actually separates these 3 valves?
So I am actually asking in my honest to God ignorance because the starboard tube whilst being inflated made a rather large bang and the other side of the tubes inflated too!
Thing is she is now holding air really well but releasing any one of the valves and the whole thing goes flat!
Thanks,if anyone has the time for answering!

I know this isn't what you asked... but just a general note that in future on a RIB when baffles are still in good condition, it is good practice to start inflating at the bow and work your way back, as doing it the opposite way can cause the cone to pop in to the chamber and it isn't great for them...

Tim M · 22 February 2021, 16:16

Quote:

Originally Posted by SimonCh

I know this isn't what you asked... but just a general note that in future on a RIB when baffles are still in good condition, it is good practice to start inflating at the bow and work your way back, as doing it the opposite way can cause the cone to pop in to the chamber and it isn't great for them...

Agreed, that's certainly something I always advocate. Furthermore, I normally inflate to around half working pressure in all compartments, then do a final top up to full working pressure, again working from the bow aft.

As has also been stated above, using a RIB with all the baffles blown really isn't a great idea, especially a Searider which has minimal inherent buoyancy due to the flooding hull. You'll want to get that fixed.