Do I really need to paint the bottom every year ?

[Duck401k]

Question - I have a fiberglass Morgan 34 - I pay to get winter storage every year and haul it to dry dock for the winter. The guys at the yard are nice but are relatively insistent that I paint the bottom every year. I keep the boat on the Chesapeake Bay and it is in the water from April until November.

Do I need to paint every year after pressure wash the bottom is clean ? Any thoughts, Thanks ?

[Maine Sail]

Depends upon what paint you use. A multi-season haul/re-launch capable co-polymer ablative won't need painting every year if there is enough film thickness. Not all ablatives are haul/re-launch capable.. A standard modified epoxy "hard" paint will become ineffective after winter storage.

[captainmurph]

Quite a bit depends on your environment and the abundance of bottom-hugging critters in your area.

Here in the Lake MI fresh water, we can get by for two seasons (even with the hard that become ineffective after a winter on the hard). In many other areas, the answer is effectively: Yes, you should do each spring - particularly where the water stays warm.

But, the key word is ablative. The paints that slough off continually to provide growth protection are continually wearing off while in the water. When hauled, they just hibernate and continue to work into the next season.

I've used these for years and like the ability to touch them up without a full recoat. Want a blue or green bottom? Make you first overall coat (after preparation of old substrate) in red. Then make another two coats in your final color.

As the paint "ablates" (I think that's a word!), you'll know when it is time to renew with the presence of the red areas.

Here's more info on Petit paints. Check out West Marine and Defender for other (including "house" brands.

[PCP]

Originally Posted by captainmurph

Quite a bit depends on your environment and the abundance of bottom-hugging critters in your area.

... In many other areas, the answer is effectively: Yes, you should do each spring - particularly where the water stays warm.

But, the key word is ablative. The paints that slough off continually to provide growth protection are continually wearing off while in the water. When hauled, they just hibernate and continue to work into the next season.

...

Good advise. I will add that it also depends on the number of miles you do for season and the average speed of the sailing. Your anti-fouling, if it is an ablative one, will have a bigger erosion if you make a lot of miles or if you sail fast or with heavy weather.

I have tried the ones that are supposed to be effective on two seasons, but they are more expensive and the results are not very good.

In my case, I have found out that the most effective and economic way was using an inexpensive anti-fouling (the one used on the shipyard) and to have a single coat every year, except on the rudder and keel, where I put two coats.

[sailingdog]

If you're using an ablative, it is probably a wise idea to put at least one, preferably two, extra coats at the leading edge of the keel, rudder, bow and waterline... since these are higher-wear areas.

[Maine Sail]

Originally Posted by captainmurph

But, the key word is ablative. The paints that slough off continually to provide growth protection are continually wearing off while in the water. When hauled, they just hibernate and continue to work into the next season.

You need to be a careful in choosing a true multi-season haul/re-launch capable albative. They are not all haul/re-launch capable.

Paints a that are re-launchable:

Pettit Ultima (complete Ultima line)
Pettit Horizons
Pettit Hydrocoat (waterbased multi-season ablative)

West Marine PCA Gold

Interlux Micron
Micron Extra
Interlux Micron 66 (freshwater use/salt kills this paint)

Generally the co-polymer ablatives can be re-launched. There are quite a few ablatives that loose effectiveness when dry stored..

One other point of reference is that the Pettit co-polymer paints, including West Marine PCA Gold, begin to ablade at low speeds, about 3 knots, while the Interlux co-polymers Micron & Micron Extra, don't start until 6-7 knots. Low speed ablading is well suited for sail boats to minimize paint build up and to continue exposing fresh copper to prevent growth.

Micron 66 self ablades but can't be used in salt water..

[lancelot9898]

Originally Posted by PCP

Good advise. I will add that it also depends on the number of miles you do for season and the average speed of the sailing. Your anti-fouling, if it is an ablative one, will have a bigger erosion if you make a lot of miles or if you sail fast or with heavy weather.

I'll add my two cents FWIW. I too am in the Cheaspeake and haul every three years and when I do I put a multi season ablative bottom paint on. This past year I used an ablative by Blue water. Blue something. It received some good ratings in Practical Sailor. On their website they also sell to the commercial industry and have one gallon size containers in addition to the larger size so I thought about getting the commercial ablative since the website talked about it lasting for up to 5 years. When I talked to the rep about it he said that the reason for going that long between coatings was that these ships were doing thousands of miles and even if I'm using the boat every week which I do thoughtout the seasons, the wear on the ablative would not be suffiecient to give enough protection. I thought it strange that wear was necessary to achieve more duration, but apparently that is the case with the commericial shipping. I'm happy with the three years, but always looking for a better approach.

[Fstbttms]

Originally Posted by lancelot9898

When I talked to the rep about it he said that the reason for going that long between coatings was that these ships were doing thousands of miles and even if I'm using the boat every week which I do thoughtout the seasons, the wear on the ablative would not be suffiecient to give enough protection. I thought it strange that wear was necessary to achieve more duration, but apparently that is the case with the commericial shipping.

I suspect that what he was actually telling you was that commercial ships tend to be kept moving as much as possible throughout their lives. They spend very little time moored or at the dock and therefore tend not to ever get very foul. This is why they can get so much use from a bottom job. Your boat, even if you used it very frequently, would spend a much greater percentage of its life sitting in its slip, getting foul.

[scraph]

What is the lifetime of a hard bottom paint? VC Offshore, for example? How do you know when it is time for a recoat of a hard paint? Thickness remaining is a great telltale with ablative paint ... but what about VC Offshore? All that grows around here is grass on the hull. No barnacles/oysters/calcium deposits whatsoever. If a low-abrasive underwater scrub keeps the hull clean, at which point should I stop cleaning the current coats and put on new?

[Fstbttms]

Originally Posted by scraph

What is the lifetime of a hard bottom paint?

Completely dependant on the product, fouling rate, frequency of cleaning, boat usage etc. We don't see VC Offshore here in the Bay Area (or any Teflon paints, for the most part) but with frequent, gentle cleanings, a good modified epoxy paint will last 3 years.

Originally Posted by scraph

If a low-abrasive underwater scrub keeps the hull clean, at which point should I stop cleaning the current coats and put on new?

When the paint stops being effective. If you, or your diver, find the hull fouling at an increased rate between cleanings, or the bottom is becoming increasingly difficult to clean, it's time to think about new paint.