Copper coat - yes or no ?

[Boatbore]

I have had the trim tabs reconditioned, and you are quite right in that they are massively engineered. I didn’t entirely understand why they are vulnerable when say reversing, and why it would make any difference if the middle prop was spinning or not ? The tabs work well and as I mentioned before the boat is very sensitive to trim so I need them to be fairly precise.

With respect to manoeuvrability though, I haven’t as yet had any problems, and she manoeuvres relatively easily. Perhaps not as well as a more conventional boat with shafts, but it seems like that is more to do with the narrow beam and the props being relatively close together than because of the trimax drives. So far I have found her relatively ok to manoeuvre.

 

[Boatbore]

Trim tabs.

And the actual tab cylinder:

 

[Boatbore]

Thanks for fulfilling my desire!

Btw, sorry if I'm teaching you to suck eggs, but don't forget to check periodically that those internal flaps inside the ventilation exhausts don't get stuck due to marine growth.
They are important to avoid water reversion in some peculiar conditions, like reversing with the central engine turned off (something you might be tempted to do since it's useless upon maneuvering) or mooring the boat in some place where current can occasionally flow against the stern.


Sorry...... you were referring to the ventilation tubes not the tabs...... they don’t have a valve in them, they are literally just a tube to a hole in the transom above the waterline. As the props spin they suck air in to create that ventilation. I think you are thinkin* of those surface drives that use the boats own exhaust to give the ventilation. Presumably those need a flap or valve

 

[MapisM]

In hindsight, I realize that my previous posted was somewhat cryptic, sorry about that. Following the order of your questions:

1) ref. how much can the prop scratches affect performance, TBH I think not a lot, though if you would ask Philip Rolla I'm almost sure that he would disagree.
Otoh, if you are not going to put any antifoul on props (which might not last, anyway), mirror-like finishing is better to reduce the growth, and also for self-cleaning it upon usage.

2) when I mentioned the "flaps inside the ventilation exhausts", I wasn't talking of the trim tabs. Trim tabs are as you say built like tanks, and have no vulnerability in any position.
In principle, it's always better to raise them fully before mooring, and leave them raised till the next usage, but just for better maneuverability and reduced exposure to marine growth of the piston.

3) the flaps I was talking about are the round discs inside the exhaust exits behind the upper part of the props, usually called "ventilation exhausts" since they are meant to throw air at the props, facilitating their cavitation when accelerating from displacement speed (when they are fully submerged, hence not working as they are designed to work).
If sea water flows back through those exhausts (which is what I meant by "water reversion"), it can in the worst case reach the turbine or even find its way inside some cylinders, potentially wrecking the engine.

I hope this is clearer, but if not, just shout!

 

[MapisM]

Sorry...... you were referring to the ventilation tubes not the tabs...... they don’t have a valve in them, they are literally just a tube to a hole in the transom above the waterline.

Doh! Sorry, I wrote my reply above before reading your post.
Yep, that's what I meant, and I would have sweared that in the original Buzzi Trimax those were designed as exhausts.
But if in your boat they aren't, just forget my previous comment!

 

[KevB]

Definitely CC. 12 years on and still working. Applied it with a couple of friends, couldn't be easier.

 

[Boatbore]

Thanks KevB. What sort of boat ?

 

[BartW]

Ditto - hope you have a good recovery rubber duck.

@hurricane Ok but there are zillions of boats with zero Mxx problems over many years including mine and MYAG's so there was something else at play in your case. Incorrect primer or something. A large part of the super yacht fleet has used m66/77 for years because of its 2 year life. I've never had it rub off on swimmers and this thread is the first time I've heard of that. I find the stuff amazingly good and my hull is clean when I haul out, and it's black. I wouldn't dream of using CC and its (imho) ugliness and fussy application "rules", and high cost.

+1 to everything posted above,

in jan 2017 I had a liftout and softwash for getting a clean hull for engine tests / sea trial, (no new AF)
before summer we didn't need to lift her again and didn't put a new layer of Micron 77 as we were used to do the previous years,
so that was the first time we did two seasons with the same AF,
we were quite surprised with the good condition when we lift her out in november 2017.

the last few years we didn't do any prop treatment, I have dive gear and scrub them regularly,
4 years ago we had applied Velox, and that gave some positive results, (good enough until the end of the summer...)
if they have the product here in the south of Italy, I might use it again

 

[maby]

If you do have Coppercoat applied, make sure that you get a good warranty from the contractor that applies it. We had our second boat Coppercoated from new - the hull had never been in the water before it was applied. It was done by a professional paint-shop who abraded the hull, applied an epoxy undercoat followed by the recommended number of coats of Coppercoat. It worked well enough - kept the hull pretty clean for the first year - but, within 18 months of application, significant areas were falling off. It's expensive stuff and you need it to carry on working for several years before it pays for itself. In our case, the paint-shop accepted liability and agreed to patch it up. We sold the boat shortly afterwards, so I don't know how well it has lasted in later years.

If you are applying it to a hull that has been in the water for a while and has received other antifouls, then you need to have confidence in the standard of preparation that the contractor carries out before application. And you need a warranty running for several years - it still needs to be well attached after four or five years if it is to justify itself!

 

[EugeneR]

On the same theme, anyone use propspeed ? Any good ?

Yes. Approx. four months on the Hamble almost unable to plane. As per the respected outfit that applied it, "was as if nothing was applied". Did not do what it said on the tin. Difficult to get rid of it or redo later. I would avoid at all cost now.

 

[EugeneR]

Yes for Coppercoat. Still doing an annual lift and hold for anodes, maybe an extra lift and wash before a long trip, but not missing the weekends of sanding and painting in 5 degrees to be ready for splash weekend..

 

[maby]

Yes for Coppercoat. Still doing an annual lift and hold for anodes, maybe an extra lift and wash before a long trip, but not missing the weekends of sanding and painting in 5 degrees to be ready for splash weekend..

I'll second that - the benefits of Coppercoat are more a reduction in effort and loss of use of the boat than financial savings - you still have to lift the boat for cleaning, anode changes and other maintenance. The financial benefits are probably greater for mobos than for sailing yachts (like ours) - a quick coat of soft antifoul over the top of last year's treatment after a good pressure wash will last us a year - you speed-freaks need to use something harder, slippier and altogether more expensive!

 

[KevB]

Thanks KevB. What sort of boat ?

35' planning hull. Kept UK south coast, Chichester. I come out of the water every other year and have never had to clean the hull, the job the yard does when taking her out is all that is needed.
I do maybe once or twice in the summer when at anchor swim around the boat with a green abrasive pad and rub the coppercoat water line but that's it.

In Chichester marina we do sufferer every now and then with the dreaded worm and on these occasions the trim tabs become covered. It has sometimes bled an inch or two onto the hull but a couple of minutes with brick acid and wire wool removed it from the effected CC area around the trim tabs.

We applied it ourselves at a cost of around £600, three of us did it in just a few hours. As said before, it takes about 4 coats and each coat must be applied over the previous whilst it's still tacky. We used small foam rollers, no different from rolling paint onto a wall.
It's been on around 12 years and still performing as it did on year one.
No brainer really.

Just to add, we had the old antifoul removed by soda blasting which keyed up the hull nicely for the coppercoat.

 

[Boatbore]

All helpful, thank you. I have asked for the paint shop to quote for CC so I will be able to directly compare one with t’other price wise. I will report back in due course.

 

[Boatbore]

Just to resurrect and conclude this thread. I did go ahead with the copper coat plan. Sprayed on by Desty’s and a very proper job done too. 6 weeks back in the water and no beasties or fouling. Unfortunately no increase in speed either. My boat is a sunseeker Superhawk 50 and pre coppercoat managed 47.5 knots flat out, lightly loaded. She is very sensitive speed wise to anything, and will lose 5 knots with barnacles on props and shafts alone so I expected to see a difference (for good or bad) but on post coppercoat testing, achieved pretty much the same numbers give or take 0.5 knot. Conditions and water temp not identical but broadly similar, and I concluded that the previous antifoul was actually a very smooth finish already so there was little gain.
I recommend the product (so far) but suspect that the real advantage is going to be the £ saving on re-antifouling, or rather not having to, rather than on anything fuel or performance related.

 

[dimulius]

Hi Boatbore,
Well, to conclude the thread you need to post some long(er) time experience
What is the current status? Are you still happy with Coppercoat?

 

[Hurricane]

From my point of view, a couple of years ago we had to have the boat out of the water for about a month for some other work so I rubbed the old Coppercoat down and applied another two coats.
Basically, just topped it up.



That was March 2019
I manged to get her out of the water for a few hours to do the anodes last September.
This was the state of the Coppercoat then.



So to recap, the original Coppercoat treatment was done on 2012.
Patches and waterline redone in 2018
Then the whole boat topped up in 2019
At this moment in time, there is quite a lot of copper on the bottom so probably good for another 8 to 10 years.

 

[Boatbore]

Hi Boatbore,
Well, to conclude the thread you need to post some long(er) time experience
What is the current status? Are you still happy with Coppercoat?

3 seasons later and all is well. I had a small hiccup when the copper coat bubbled in a few, relatively small, places during the winter of 2018/19. When I spoke to Destys about it they confessed that they had had an issue with the compressor and had left too long between coats but that the manufacturer had sworn it would be ok. To their credit they offered to repaint the boat and sent a man down to South of France to do it. It means I lost the spray on finish, because they repainted by hand, but as I reported above I was never sure that the spraying made much of a difference.
So I guess I have had 2 seasons since then, and the coating is extremely effective at keeping the beasties at bay, as evidenced by my stern gear which gets horribly fouled. I think that the slippery nature of the copper coat combined with the speed of the boat effectively washes everything off every time I go out.
in terms of maintenance I have done nothing, and no touch up required. I do have the bottom lightly sanded (just a manual once over with a sanding block) when she goes back in but otherwise so far so good !
3 seasons since I paid for anti foul......so I am already up on the deal financially.

 

[alandalus11]

+1 for Coppercoat

 

[dimulius]

Thanks