Are PVC RIBs still inferior?

[BOSSailor]

Hello all,

I bought a used 10' Achilles Hypalon/CSM panel-floor dinghy this year. Just now getting around to putting it to the test considering the late start to the season. It's pretty terrible. I keep having floor panels pop out of the channels, and the whole thing has a bit of a magic carpet ride feeling to it as it undulates over the swells. Also it's awful in any sort of chop.

I'm looking at a RIB which is probably what I should've gone with in the first place. Something in the 10 foot range. I have a Mercury 8hp 2 stroke that works great, and if I'm getting a new dinghy a motor upgrade would not be in the cards this year. Usually going to be carrying two people, maybe a cooler and a few bags. Say 450 lbs, with the occasional 3rd person.

So the question: I know PVC was long viewed as a cheap alternative to Hypalon - it would get gummy, unglue, etc... I live in the Northeast with a relatively short season and don't have nearly the UV exposure someone cruising in the Caribbean would have. It seems that in the past few years PVC has advanced and while still not as good as CSM in some respects the differences aren't as significant as they used to be. I'm thinking that the premium for a CSM boat isn't worth it for my case. Anyone have any input?

Edit: I'm looking at new RIBs. All the used ones around me are hugely overpriced and/or need serious work.

 

[dlochner]

CSM/Hypalon is more resistant to UV than PVC. As you note, in the NE this is less of a problem than in the tropics. I also believe that CSM is more resistant to punctures and abrasion. PVC is much cheaper. The UV effects can be mitigated with sunbrella chaps if you take the time to make them and with a RIB, the abrasion issue is reduced because the hull is fiberglass or aluminum.

Give the folks at Defender.com a call and discuss it with them.

 

[sail sfbay]

I had an Achilles 9'6" hypalon for 9 years and sold it with the boat when sold it last year as I did not like the way it held up. I now have a $650 West Marine PVC dinghy that I keep covered 365 days a year. I am sure you can find cheaper ones but the link below is a 10' PVC dinghy that sells for $1680 from West Marine.

RIB-310 Single Floor Rigid PVC Inflatable Boat | West Marine

Check out our RIB-310 Single Floor Rigid PVC Inflatable Boat and more from West Marine!

www.westmarine.com

 

[RoyS]

Have a PVC Mercury Roll up. Has 12 seasons and no obvious deterioration of the PVC fabric. In the sun without covering all summer. Had one puncture on the bottom which I patched a few years ago. Wooden slats should be repainted but are good enough for now. If I was buying another I would stay with PVC.

 

[Hunter216]

You might want to look at Highfield - aluminum vs Frp hull

Highfield Boats | Dare to explore

Highfield Boats - The World's #1 Manufacturer of Aluminum Rigid Inflatable Boats (RIB) and Tenders. Find a Dealer in Your Country.

www.highfieldboats.com

 

[jviss]

"Are PVC RIBs still inferior?"

I am sure the question is referring to the aspects of these that are different from CSM RIBs, the material and the seam-joining technology, i.e., the cement.

I don't think anything has changed in the material or cement technology over the last couple of decades. So, in terms of fabric toughness, UV resistance, seam integrity, etc., yes, they are still inferior.

However, while they are holding together they have just as much utility as a CSM RIB, and they are certainly less expensive.

 

[capta]

We only use inflatables with floors and have never had that problem.
I'm wondering if you have all the pieces, IE; the metal pieces that go under the tubes on both sides and connect the floorboards together. Another possible problem is that you are operating the inflatable under-inflated. They must be pumped up to nearly as hard as a basketball, allowing no flex in the tubes.
As a last ditch effort, you could make a solid 3/4" plywood floor for the main board with the little triangle separate up forward. I've done that when the original boards get too old and it makes the dinghy very stiff and comfortable.
A glass RIB is a much heavier dink and much harder to stow on deck without proper chocks. Towing one slows your boat down much more than you might imagine and is a recipe for disaster sooner or later.

 

[Kings Gambit]

I bought two years ago a PVC inflatable RIB; 20 years ago I bought a Hypalon air floor inflatable (Achilles), which I still have and occasionally use. The Hypalon has held up well but I’ve never left it out for extended periods. It’s stowed deflated and in its bag when not being used. The PVC RIB is protected w/a custom-fitted Sunbrella cover when stowed on deck, and in the water if there for week-long periods. I also routinely apply UV protectorant to the PVC tubes. The newish German-made PVC is quite durable. I expect a long life of use if properly cared for, especially if at latitudes above the tropics. One seems to hear the bad stories of failing and disrepair generally from people who do not maintain their equipment. Yeah—leave the thing tied up behind the boat for 5 years in tropical sun w/no cover or regular UV treatment, it might get gummy ahead of a Hypalon version.

 

[Brian D]

UV protectorant to the pVC tubes.

pray tell.

 

[Richard19068]

pray tell.

303 aerospace protectant maybe?

 

[jviss]

I bought two years ago a PVC inflatable RIB; 20 years ago I bought a Hypalon air floor inflatable (Achilles), which I still have and occasionally use. The Hypalon has held up well but I’ve never left it out for extended periods. It’s stowed deflated and in its bag when not being used. The PVC RIB is protected w/a custom-fitted Sunbrella cover when stowed on deck, and in the water if there for week-long periods. I also routinely apply UV protectorant to the PVC tubes. The newish German-made PVC is quite durable. I expect a long life of use if properly cared for, especially if at latitudes above the tropics. One seems to hear the bad stories of failing and disrepair generally from people who do not maintain their equipment. Yeah—leave the thing tied up behind the boat for 5 years in tropical sun w/no cover or regular UV treatment, it might get gummy ahead of a Hypalon version.

A beautifully written, beautifully argued case that there can be, under certain conditions, no difference between CSM and PVC. But, at the end of the day, it's anecdotal, and rationalization.

Take a large sample of CSM RIBS across a spectrum of storage and use conditions; and a similarly large sample of PVC RIBs across the same spectrum of use and storage conditions; and you will see longer useful life, and better toughness, better repairability on the CSM boat. I believe this is an incontrovertible fact. It is reflected in the price. Here's a data point: Defender brand model 265 model year 2020 8'6" RIB: PVC $1,974; CSM $3,162. Identical except for material. 60% more for CSM.

 

[RoyS]

Consider also transom to tube bond failures. Met several sailors who reported this problem. It may be related to oversize outboards or cheaply built boats. At least stick with major brand names and check reviews before buying.

 

[Kings Gambit]

pray tell.

Hi Brian,

Right now I’m using a product called SEAPOWER, Inflatable Boat Cleaner & Protector, which does a good job of cleaning. The “protection” claims, however, I have to accept at face value for now. I may try a different product after this one, but I imagine similarity of composition across most. The active ingredients here appear to be morpholine and turpentine, in combination with other petroleum distillates. No claim specifically for protection against UV damage although turpentine is reported to shield skin against UV light damage.

 

[Brian D]

Thanks @Kings Gambit and @Richard19068. I keep my PVC inflatable (Mercury 240) at home in its bag. But I think I should put something on the tubes to keep them from drying out. I don't use the dinghy much and I would hate to have to use it and find it in disrepair.

 

[Kings Gambit]

303 Aerospace Protectorant ingredients are given as “Trade Secret” in the data sheet, but the product claims a water-based formula that with no petroleum distillates. Not a hazardous substance.

 

[Kings Gambit]

A beautifully written, beautifully argued case that there can be, under certain conditions, no difference between CSM and PVC. But, at the end of the day, it's anecdotal, and rationalization.

Take a large sample of CSM RIBS across a spectrum of storage and use conditions; and a similarly large sample of PVC RIBs across the same spectrum of use and storage conditions; and you will see longer useful life, and better toughness, better repairability on the CSM boat. I believe this is an incontrovertible fact. It is reflected in the price. Here's a data point: Defender brand model 265 model year 2020 8'6" RIB: PVC $1,974; CSM $3,162. Identical except for material. 60% more for CSM.

Thank you for your kind appraisal! I find it hard to envision what a statistical assessment of the durability of the two material types would finally tell us with respect to costs. If the serviceable life of the PVC is statistically but 40% of CSM, all else being equal as you posit above, then the two products would be “equitably priced.“ But interestingly, the two models you mention carry the same warranty stated at 5 years. I suppose one could infer that to at least 5 yr out, the lower-priced PVC is the better purchase. Beyond that, if the CSM makes it to at least 10 years (i.e., 5 yr post-warranty) the PVC should be good for at least another two yr, post-warranty. After that, say, you spring for the cost of another PVC, NEW w/fresh warranty, still at 40% the cost of a new CSM just by comparison, with another potentially 7 yr of serviceable life. In the end, 14 yr of PVC and perhaps 14 yr on your original CSM dinghy, if it makes it that far, for essentially the same cost, give or take a few $$. Although at this point I question the supposed degradation rate of PVC with proper care relative to CSM, thus making PVC the overall better purchase even in post-warranty. But yeah, your higher-priced CSM might still be in serviceable condition for the next owner of your boat when sold, whereas a PVC model of the same age might get pitched right away. But who would care? To that end, you’re potentially giving the next guy a freebie on a few years of dinghy use with the CSM. The basic new-sales gimmick seems at work for these products. Here, pay more (for the CSM), and get more (yrs), even though it’s more yrs than you’ll ever use!

 

[CarlN]

A PVC RIB in the NE that’s out of the sun 9 months of the year is going to last many years - especially if given a monthly spray of 303. Amazing stuff. Only takes about 15 minutes to apply.

The other advantage the OP has is that he can replace the PVC RIB easily if it fails - at a good price. Defender will probably be having a sale and it will arrive in a few days- or you can pick it up. A cruiser somewhere in the South Pacific (or even in the Bahamas) would face a high price, import duties, and few, if any, in-stock locally. For them, paying more for Hypalon upfront is likely to save money and certainly headaches.

 

[jviss]

The vast majority of RIBs around where I cruise are CSM. Something to be said for a "dominant design," WRT material.

If only one could plan when a PVC RIB would fail, one could purchase the replacement in advance of that. I'd rather spend the money on CSM than risk getting stuck. But, to each his own.

BTW, I treat my CSM RIB with Aerospace 303, I'm a believer!

 

[BOSSailor]

Went out to my dinghy yesterday to find that I hadn't clicked the fuel connector on the OB all the way in, resulting in a nice volume of 2 stroke gas on the floor. I suppose that's a point for the oil-resistant nature of CSM.
I also took some pressure treated 2x3s and screwed them lengthwise to the floorboards to stiffen it. The floor is still removable since it doesn't include the front two panels (no photos, sorry), just not quite as compact as before. It did wonders for the ride, no more rippling over the chop. Looks a little gaudy but who cares - the dinghy is a 2002 and I definitely don't want to have the nicest looking one at the dock.
Looks like I'll get another year or two out of it which is all I'm asking in the face of an impending rebuild on my 2GM20F.

 

[Mark Maulden]

The best fabric dinghy cleaner I’ve ever come across is August Race. Can get it at Defender. I have not been able to find out what’s in it. UK product..