Zodiac tube end of life - what happens

[ZodiacDan]

Hi fellow RIBers,

I have a 1999 zodiac pro 470 and I have been told by a boat store that the tubes will need to be replaced due to age/sun exposure and that it is dangerous to use the boat as is.

My question is, how dangerous is it really? What is likely to happen? Has anyone had experience with older tubes dying.. what happened, was it catastrophic?
I plan to only take the boat on fairly quiet lakes and maybe pull some tubers from time to time. I also don't plan to ever be more than 1-2minutes from shore. I don't plan on trying to jump waves/wakes or hit top speed (I am too old for that). Is there a chance that the tubes start coming apart at the seams? will this cause the boat to flip if I am moving, or will the V-hull keep some stability and allow me to quickly get back to shore?

If money is no object, the obviously getting new tubes is the ideal solution. However I am not ready to spend $3k-$4k just yet.

I would really like to hear from people who have older tubes and whether they have held up fine or have they 'failed' and what did the failure look like, i.e. what happened.

Lastly, I have read some good things about RIB paint, e.g. tuff-coat.. is this an option for preventing/minimizing dangerous tube failure?

Many thanks
Dan

[spartacus]

Hi Dan - got any pictures? I suspect there must be a specific part of the sponsons (probably a seam or cone end) that's giving cause for concern. For obvious reasons a dealer/boat store will not say it's safe, if there's even a small chance it could rupture. You've probably more of an issue with heat (expansion and contraction) rather than sea/lake surface conditions as these boats didn't have pressure release valves.

I'm assuming the tubes are PVC (Zodiac's Strongan fabric). Do you know if the internal baffles have gone too?

Forget tube paint or internal internal rubber solutions - this simply masks the problem.

[ZodiacDan]

Hi Spartacus

Thanks for your reply.
I will take some pics and upload them soon.

The boat is holding air and has no specific area of concern. It is just generally worn and some areas have slight signs of the weave showing through.
The dealer didn't spend more than half a second (literally) assessing the tubes. Just touched it and said.. no its gone... and it's dangerous to ride on these.

I am pretty sure they are PVC (did the MEK test and the looking through the valve test).

I am not sure if the baffles have gone.... if I deflate one chamber... how long should the next chamber stay inflated for?

Thanks
Dan

[spartacus]

Originally Posted by ZodiacDan

I am pretty sure they are PVC (did the MEK test and the looking through the valve test).

I'm sure they're PVC too. Most of Zodiac's leisure ribs are - although they've started to make some Pros in hypalon recently.

I am not sure if the baffles have gone.... if I deflate one chamber... how long should the next chamber stay inflated for?

The other chambers should remain inflated, however try to maintain pressure across all tube sections. If they're gone - you'll probably be able to inflate the boat from one valve.

[Poly]

Originally Posted by ZodiacDan

The boat is holding air and has no specific area of concern. It is just generally worn and some areas have slight signs of the weave showing through.
The dealer didn't spend more than half a second (literally) assessing the tubes. Just touched it and said.. no its gone... and it's dangerous to ride on these

Sounds to me (from the limited information) like the dealer is being a little OTT either to get a sale for new tubes or to CYA because north americans are a tad litigious.

Old tubes normally fail in one of two ways:

(1) they just become porous - this sounds like what you might be experiencing, essentially they won't hold air for as long as you would expect. take a pump with you and you will probably be fine. Its more of an issue if you are reasonably far from safety in an environment where you can't safely top up the tubes.

(2) the seams start to fail. these are difficult to repair and on old material (especially PVC) even harder. a burst seam may be impossible to fix at sea. If the baffles are fine a single section deflating should not be an emergency. If the baffles have all gone, one seam failure would mean all your tubes deflate spontaneously.

Neither is necessarily a Mayday! A well designed RIB (I can't comment on your specific boat) should stay afloat even with all the tubes deflated. Certainly with a single tube segment burst or the tubes going soft in the middle of the day you should be able to limp to shore.

Generally unless very well cared for 10 yrs is normally suggested as the life of a PVC tube, and so for a 13 yr old boat your might be able to nurse them on for another couple of years but you do need to plan for the inevitable.

[captnjack]

I have never seen a PVC boat native to the Pacific Northwest die of sun exposure. Not saying it doesn't happen but we don't get that much sun/UV and most folks cover their boats. If it came from California or someplace sunnier that's obviously a different story.

"Weave" showing through is strange to me, are these abrasions?

[ZodiacDan]

I think these must be abrasions then, but there are multiple areas... maybe used as a dive boat? Not sure if you can see from the attached image. I will try to take some better pictures.

I think this boat was just used a lot.
The tubes aren't sticky. If anything they are a bit dry/matte.

I basically wanted to know if I can do some light boating in safe environments (i.e. lakes, close to shore), maybe pull some tubers/skiers for the next year and then consider tube replacement when I have more money.

I didn't want to risk my, or my families, safety but I wanted to understand how and old tube becomes unsafe and what the possible risks are. I have read some stories of people's RIB tubes suddenly rupturing or detaching (due to many reasons, not just age) and in all cases the boat still got back to shore ok.

[captnjack]

Yes that might be a bit of abrasion but the weave itself is still intact so I doubt much strength has been compromised.

PVC tubes basically fail in 2 ways:
1) They become brittle due to age, UV, and /or heat. Lots of pin hole leaks and heavily faded fabric are the main indicators typically.

2) The main tube seems (in your pic) are thermowelded and almost never fail. Portions of the tubes are glued however. The main glued seam on your boat is probably the attachment of the bolt-rope to the tube. (the rope that slides into the hull slot, not the safety line around the outside). Another glued seam which often fails is the floor of a SIB which you don't have to worry about.

If the tubes aren't heavily sun faded and leaking through various pin holes, I would examine the boltrope connection for any signs that its peeling or seperating from the tube. If those 2 things are not cause for alarm then I would continue to use the boat for awhile.

I have bought 12 yr old PVC boats in excellent condition, so age alone is a poor indication of remaining life.

[ZodiacDan]

Hi CaptJack,

Thanks for your response.

What is the best way to check the bolt rope? Do I deflate the tube totally and then check where the tube meets the main hull

The only picture I could find is this one
:: OutBoard Direct ::

but it is hard to see any detail in the image regarding the bolt rope location.

Thanks,
Daniel

[paul tilley]

try using it with the tubes deflated , if you think it is safe for your requirements re-inflate and tie a rope over the tube in the bows to hold the tube down in case the bolt rope comes off .you can the use the boat whilst saving for new tubes

[ZodiacDan]

Originally Posted by paul tilley

try using it with the tubes deflated , if you think it is safe for your requirements re-inflate and tie a rope over the tube in the bows to hold the tube down in case the bolt rope comes off .you can the use the boat whilst saving for new tubes

So, in theory a RIB should float (and even drive) in calm water with the tubes deflated?

Could you explain how I would tie the tubes (sounds like a vasectomy )
Would a tie a rope through the grab handle and across to the grab handle on the other side? or would the rope somehow be attached to the actual hull?

Thanks,
Dan

[Poly]

From the picture you posted they don't look that bad. If they are holding air for 1 day+ and the baffles are intact too then you have a good start.

In theory your boat should float with the tubes deflated. You can test this (probably best to deflate slowly until you start to get concerned).

I think what Paul was suggesting is that a rope from the bow eye on the GRP hull up over the tube at the front and secured somewhere inside the front of the boat (perhaps an anchor locker) will reduce the risk of catastrophic detachment.

[paul tilley]

polwart is correct ,tie from bow eye over tube to inside of boat

[ssobol]

Originally Posted by ZodiacDan

So, in theory a RIB should float (and even drive) in calm water with the tubes deflated?

I think this will depend on the exact nature of the failure. If a front chamber goes it should be possible to still drive the boat. If an aft chamber goes perhaps not. It will depend on the weight you are carrying and the distribution.

On my Zodiac, the weight it concentrated at the back (engine, battery, fuel, driver). The aft ends of the tubes are in contact with the water most of the time. The front part of the tubes rarely touch the water (the hull rises towards the front) even at idle speeds.

If the tube separates from the hull at the back of the boat the hull is likely to remain afloat but will probably be awash. I don't know if you can drive it this way, but it should not sink.

[jyasaki]

Originally Posted by ssobol

On my Zodiac, the weight it concentrated at the back (engine, battery, fuel, driver). The aft ends of the tubes are in contact with the water most of the time.

Question is where the highest point of the hull sits with relation to the waterline. Losing a tube (or section, I should say) should not affect buoyancy enough to allow water over the hull, at least at rest. Don't know about underway, but I'd think you'd get some amount of lift off the hull, which should help.

I think having the tubes go at the front would be a worse scenario, as any water getting in there (and there will likely be a lot as you beat into seas) will pool in the hull, reducing overall buoyancy.

All speculation on my part, though.

jky

[captnjack]

Originally Posted by ZodiacDan

Hi CaptJack,

Thanks for your response.

What is the best way to check the bolt rope? Do I deflate the tube totally and then check where the tube meets the main hull

The only picture I could find is this one
:: OutBoard Direct ::

but it is hard to see any detail in the image regarding the bolt rope location.

Thanks,
Daniel

The boltrope is labeled here. When the bow pushes into a wave is when+where it sees the highest forces pulling the boltrope away from the tube. The bow portion of the tube then rips off the hull and folds back over the operator. So that's the most critical area to be checking for old dried out glue and potential failure.

[ZodiacDan]

Originally Posted by Polwart

From the picture you posted they don't look that bad. If they are holding air for 1 day+ and the baffles are intact too then you have a good start.

In theory your boat should float with the tubes deflated. You can test this (probably best to deflate slowly until you start to get concerned).

I think what Paul was suggesting is that a rope from the bow eye on the GRP hull up over the tube at the front and secured somewhere inside the front of the boat (perhaps an anchor locker) will reduce the risk of catastrophic detachment.

thank you, i will check the baffles. Do I do this by deflating one chamber and seeing if the neighbouring chamber deflates?

[captnjack]

Originally Posted by ZodiacDan

thank you, i will check the baffles. Do I do this by deflating one chamber and seeing if the neighbouring chamber deflates?

In theory each chamber should be able to take full pressure. If you deflate one the neighboring ones will push the baffle towards the empty one and so appear to have leaked themselves. So try deflating every other chamber. Then inflate the remaining chambers until they are at least full shape - to full pressure if you choose. They should remain full at least overnight. Then repeat deflating the full ones and inflating the formerly empty ones. Then you'll have confirmed that each chamber is holding air on its own and not leaking into either an adjacent chamber or to outside.

[gjayson]

Hello,

We have a 2001 zodiac open pro in the Long Island Sound area. This season we had some serious leaking and upon hauling the boat have discovered that the leaks are coming from the seals towards the stern. The underside of the tube seams to have a fair amount of breakdown, but it is certainly the seals where the leaking is happening. I wondered if anyone has ever successfully patched/repaired this problem to get a few more seasons out of the current tubes? Or is it a lost cause as the tubes are now 11 years old? Also, what is the cost of full replacement? Would it make more sense to replace with hypalon? (currently have PVC) or would that be entirely more expensive and harder to do with a zodiac? Many thanks in advance for any help people can provide.

Thanks, GJG

[Locozodiac]

If general fabric condition looks old, faded, whatever, you can find in the market fabric rajeunissement products that will make that fabric look in near mint conditions again.. Afterwards can apply a good overdose of Aerospace Protectant 303 for sun's UV extra protection.

Happy Boating