Antifouling a small RIB - hard racing or self eroding?

[alexincornwall]

This might be one for the motor boat specific community but I'll start here. We've recent acquired a small RIB (3.3M with console steering and 20 horses hanging off the back). I estimate it will push along at a max 18-20 knots, perhaps with a more sensible cruising speed of 12. The idea is to use the boat as a fast tender to our yacht on our shorter trips, but also as an independent craft for standalone use, hence I've negotiated a tender space on the pontoons. I'd like to keep the boat afloat for most of the year but can easily undertake maintenance as the boat is very easily moved around on its trailer.

The boat has never been antifouled so will require the waterline marking up, prep and priming, and then the antifoul itself. This is where I am confused. My initial thought would be that it's faster than a yacht so hard antifoul would be the way to go but from what I have been advised, the boat appears to be a suitable candidate for either hard or self-eroding paint due to its lower max speed than most RIBs and powerboats. We usually get good results using Seajet 033 on the big boat but rarely exceed 8 or 9 knots. I was surprised to read that Seajet is 033 is rated up to a max speed of 40 knots and am unsure whether this claim would match the reality, especially for a small RIB which is likely to bounce around a bit more.

I would have thought that the self-eroding would be more efficient when it's sat there doing nothing, but would essentially fall off when the boat reached any speed. Likewise, I suspect that the hard antifoul wouldn't do so well in the marina, but would perform far better at speed, potentially cleaning itself.

I'm also mindful that I could try hard racing and if that didn't work could then convert to self-eroding, but it might be problematic to go the other way around.

Any thoughts please?

 

[Tranona]

Starting from scratch seems an ideal candidate for Coppercoat.

 

[lustyd]

Most RIBs around us use a floating dock so they just motor up onto it when they get to the marina and never need antifoul. That or they use dry stack instead - similar price but keeps the boat under cover and out of the water.

I'd certainly do my best to avoid antifoul as it will eventually foul and ruin performance, not to mention the cost of paint and lift outs would make a dry stack more attractive

 

[alexincornwall]

Starting from scratch seems an ideal candidate for Coppercoat.

That would be a nice thing to do but a lot of work for a <11 foot boat.

 

[alexincornwall]

Most RIBs around us use a floating dock so they just motor up onto it when they get to the marina and never need antifoul. That or they use dry stack instead - similar price but keeps the boat under cover and out of the water.

I'd certainly do my best to avoid antifoul as it will eventually foul and ruin performance, not to mention the cost of paint and lift outs would make a dry stack more attractive

Unfortunately we don't have such luxuries at our marina. I could tow the boat home after every outing but I think the level of hassle would have a big impact on how often we would use the boat.

 

[Plum]

This might be one for the motor boat specific community but I'll start here. We've recent acquired a small RIB (3.3M with console steering and 20 horses hanging off the back). I estimate it will push along at a max 18-20 knots, perhaps with a more sensible cruising speed of 12. The idea is to use the boat as a fast tender to our yacht on our shorter trips, but also as an independent craft for standalone use, hence I've negotiated a tender space on the pontoons. I'd like to keep the boat afloat for most of the year but can easily undertake maintenance as the boat is very easily moved around on its trailer.

The boat has never been antifouled so will require the waterline marking up, prep and priming, and then the antifoul itself. This is where I am confused. My initial thought would be that it's faster than a yacht so hard antifoul would be the way to go but from what I have been advised, the boat appears to be a suitable candidate for either hard or self-eroding paint due to its lower max speed than most RIBs and powerboats. We usually get good results using Seajet 033 on the big boat but rarely exceed 8 or 9 knots. I was surprised to read that Seajet is 033 is rated up to a max speed of 40 knots and am unsure whether this claim would match the reality, especially for a small RIB which is likely to bounce around a bit more.

I would have thought that the self-eroding would be more efficient when it's sat there doing nothing, but would essentially fall off when the boat reached any speed. Likewise, I suspect that the hard antifoul wouldn't do so well in the marina, but would perform far better at speed, potentially cleaning itself.

I'm also mindful that I could try hard racing and if that didn't work could then convert to self-eroding, but it might be problematic to go the other way around.

Any thoughts please?

International Micron 350 eroding antifouling will work well for your use and speeds. If you apply the correct film thickness it can last 2 years. Recommended.

 

[lustyd]

Unfortunately we don't have such luxuries at our marina. I could tow the boat home after every outing but I think the level of hassle would have a big impact on how often we would use the boat.

The floating dock is usually owned by the boat owner https://www.tetradock.com/ and although pricey would pay for itself relatively quickly compared to lift outs and antifoul.

Falmouth has a dry stack, and I believe there's another planned nearby. Wouldn't be surprised to see Mylor get one too before long. Where is the pontoon you're going on?

 

[Tranona]

That would be a nice thing to do but a lot of work for a <11 foot boat.

Little more than applying conventional paint as you are starting from a clean base. Five coats instead of 3 and no more for the next 10 years or so. Day's work on a small boat. No brainer to me.

 

[fredrussell]

I’d just leave it as is. It’s small enough to easily run it up the beach/slipway/hard and just give it a scrape once in a while.

 

[thinwater]

Most hard paints, including Coppercoat, will deactivate if they dry out (davits). Some can be reactivated with a stiff scrub with light abrasive.

Only you know your actual use patterns. The practical differences between hard paints and good durable multi-season self-polishing paints is probably less than you perceive.

 

[alexincornwall]

The floating dock is usually owned by the boat owner Drive-On Floating Docks for RIBs, Boats & Jet Skis | Tetradock and although pricey would pay for itself relatively quickly compared to lift outs and antifoul.

Falmouth has a dry stack, and I believe there's another planned nearby. Wouldn't be surprised to see Mylor get one too before long. Where is the pontoon you're going on?

That does look interesting. Unfortunately, we don’t have a finger berth, they’ll probably just stick us on the outside of the eastern pontoon with the tenders. My budget won’t stretch to a dedicated berth for this boat - as my wife keeps reminding me, this is number four…

 

[Hadenough]

Little more than applying conventional paint as you are starting from a clean base. Five coats instead of 3 and no more for the next 10 years or so. Day's work on a small boat. No brainer to me.

Coppercoat on a RIB? OP doesn’t say what the hard hull is, aluminium, GRP?? But some of the inflatable tubes are going to be submerged regardless. Can you coppercoat hypalon, PVC, or whatever else they use nowadays?

 

[Chiara’s slave]

Coppercoat on a RIB? OP doesn’t say what the hard hull is, aluminium, GRP?? But some of the inflatable tubes are going to be submerged regardless. Can you coppercoat hypalon, PVC, or whatever else they use nowadays?

This, exactly. Sorry to say I think it’s a terrible idea to keep it in the water. I guess you could antifoul or copper coat the rigid bit, but the tubes will need the very nearly useless flexible hypalon antifoul, the aluminium motor mount will need Trilux or equivalent, you’ll never get to all the bits that will be immersed, and it will look tatty and sad, and go slowly. We have a Novurania 3.35 with the same problem. We have dry stored ours on a trolley in the dinghy park, but are going floating dock next year, cos it is so heavy. The other possible option is a pvc fully immersed dock, which empties and wraps the hull. Not tried it, but I’m assured they work well. The one thing I can personally say from previous RIBs is that antifouling them is a sad disappointment.

 

[Hot Property]

This, exactly. Sorry to say I think it’s a terrible idea to keep it in the water. I guess you could antifoul or copper coat the rigid bit, but the tubes will need the very nearly useless flexible hypalon antifoul, the aluminium motor mount will need Trilux or equivalent, you’ll never get to all the bits that will be immersed, and it will look tatty and sad, and go slowly. We have a Novurania 3.35 with the same problem. We have dry stored ours on a trolley in the dinghy park, but are going floating dock next year, cos it is so heavy. The other possible option is a pvc fully immersed dock, which empties and wraps the hull. Not tried it, but I’m assured they work well. The one thing I can personally say from previous RIBs is that antifouling them is a sad disappointment.

I would agree with you.

I had my 5.2 metre rib on a 365 day berth on the Hamble

I used Silic One on the hull - a great success.

However the tubes at the rear sat in water permanently. I used correct PVC antifoul and it lasted a day.

It fouled up pretty quickly and was a pain to remove small barnacles. As I towed it to a few locations for rallies I had the chance to clean the tubes once on the trailer.

I now have a 20ft cuddy (with Silic One of course) and the only bit of the boat subject to fouling is the bottom third of the outboard bracket. Negligible effect on performance as above the keel line.

Next time I'll apply any coating to the hull will be 2028, four years after initial application, and then only 1 coat of Silic.....

 

[Ribtecer]

This, exactly. Sorry to say I think it’s a terrible idea to keep it in the water. I guess you could antifoul or copper coat the rigid bit, but the tubes will need the very nearly useless flexible hypalon antifoul, the aluminium motor mount will need Trilux or equivalent, you’ll never get to all the bits that will be immersed, and it will look tatty and sad, and go slowly. We have a Novurania 3.35 with the same problem. We have dry stored ours on a trolley in the dinghy park, but are going floating dock next year, cos it is so heavy. The other possible option is a pvc fully immersed dock, which empties and wraps the hull. Not tried it, but I’m assured they work well. The one thing I can personally say from previous RIBs is that antifouling them is a sad disappointment.

And it de-values them massively.

Most people are left wondering why was it antifouled? Was it to cover up damage???

 

[alexincornwall]

Thanks everyone for the input on this - an interesting read and I would not have predicted the strong argument for not antifouling at all. Definitely something to think about.

I'm not a RIB expert or fanatic by any stretch but I have friends that are and whose boats live afloat for the season and sometimes beyond. They all antifoul their boats and only one attempts to coat the tubes. They haven't reported any horror stories but I'll double check.

I think removing the boat from the water one way or another after each outing is going to detract from the enjoyment of having a boat ready to go at a moment’s notice so I don't think that's an option for me, but I'm happy to concede that a full year afloat isn't going to do the boat any favours without regular maintenance (the same as the "mothership" of course).

 

[Ribtecer]

Then get one that's already been A/F'd

 

[alexincornwall]

Then get one that's already been A/F'd

Thanks. As per original post I've already bought the boat which has not been antifouled (yet).

 

[greeny]

I coppercoated the grp hull and then used a flexible hypalon antifoul on the tubes which turned out to be useless. Now I can't get it off the tubes and it looks a mess. So my recommendation is to do the hull but just accept that you will have to clean the tubes every few weeks. I'm going to have another go at getting the rubber antifoul off this winter and cleaning the tubes back to original, but don't think it will ever fully come off. The rubbery antifoul is too soft to try to sand in any way, can't be scraped off and there seems to be no known solvent to try to "wash" it off.

 

[Chiara’s slave]

I coppercoated the grp hull and then used a flexible hypalon antifoul on the tubes which turned out to be useless. Now I can't get it off the tubes and it looks a mess. So my recommendation is to do the hull but just accept that you will have to clean the tubes every few weeks. I'm going to have another go at getting the rubber antifoul off this winter and cleaning the tubes back to original, but don't think it will ever fully come off. The rubbery antifoul is too soft to try to sand in any way, can't be scraped off and there seems to be no known solvent to try to "wash" it off.

That is my finding too. Then there’s the immersed parts of the motor(s). Which is why our little baby is not going to be antifouled. All motor boats suffer some of these issues, but on small RIBs it’s just horrible.