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Hull Area? Bottom Painting

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C255885
Deckhand

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USA
3 Posts

Initially Posted - 10/19/2011 : 18:08:48

Can anyone tell me the hull area of an '89 25? I am getting ready to do my first bottom painting and can not find any specifics on the area of the bottom that I'll be painting. Do I get three gallons or four or more? Also, the owner's manual says not to sand the original bottom and to use a no sand primer. how can i tell if i have the factory norm or if has already been painted and therefor NA. Anyone have any advice?

Thanks in advnace.

Edited by - on

Prospector
Master Marine Consultant

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Canada
3159 Posts

Response Posted - 10/19/2011 : 18:53:31

What kind of bottom paint? This question usually comes up in te spring, so a search may find theanswer you are looking for. You should try to match the previous bottom paint if you can. My bottom is VC17m and we use just over one can per year. Technique is very important with this type of paint though, or you will go through much more.

Edited by - on

C255885
Deckhand

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USA
3 Posts

Response Posted - 10/19/2011 : 19:00:07

thanks, I looked at the VC 17 but wanted to go with ablative rather than the hard epoxy and the removal thereof in future years. I have done sevral searchs and still trying to find the bottom area.

Edited by - on

Stinkpotter
Master Marine Consultant

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Djibouti
9076 Posts

Response Posted - 10/19/2011 : 19:31:10

For one coat, I used about 2/3 of a gallon. I thinned it slightly with the prescribed thinner, especially on a warm day when it wanted to thicken up while I was working. I'll defer to fresh water sailors on recommending paints...

A common technique with ablative paint is to use one color for the first coat--the "signal coat"--and then a contrasting color (the one you like) for all succeeding coats--generally one every 2-3 of years. Until you see evidence of the signal coat, you don't need to add paint. What you have left (the 1/3 gallon) can be used in the "off" years to touch up areas that have worn or flaked.

Is the bottom bare gelcoat now? If it's paint, you need to know what, and check compatibility with what you're thinking about applying... If not, then sanding the gelcoat is indeed not recommended--it increases its permeability and thereby promotes blistering. No-sand primer can be tricky--follow the instructions precisely to apply the paint at the right time after the primer. Generally, if you wait too long and the primer has no "tack", the paint won't adhere properly. Before priming, use a solvent to remove any residual mold release wax (or wax a P.O. might have applied to the bottom)--vestiges of it can last for years and literally make your paint fall off.

Edited by - Stinkpotter on 10/19/2011 19:40:08

Lee Panza
Captain

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USA
465 Posts

Response Posted - 10/19/2011 : 20:00:03

In preparation for re-coating my (boat's) bottom I took a series of measurements at every foot along the length of the keel, stretching a flexible tape from the centerline (or, with an adjustment for the offset, from the edge of the keel trunk recess of this swing-keel model) along the surface up to the top of the uppermost boot stripe, and then I reproduced the measurements in an AutoCAD polyline. AutoCAD automatically calculates the area within a polyline, and it yielded a figure just under 75 square feet for each side of the bottom (150 SF for the whole bottom), not including the keel or inside of the keel trunk recess. This includes the additional surface area toward the aft end where the bottom develops an integrated keel form.

In most cases one would not run the bottom paint up over the boot stripes, but I ran the barrier coat up that high.

From measurements taken on my swing-keel I calculated 26 SF for the area accessible when the keel is installed (lifting and lowering it to get the radiused forward portion as well). A conventional fixed-keel would have more surface area, and I suspect that a wing-keel might also.

So, 100 square feet is a good starting point for estimating coverage on a swinger (not including the rudder), but someone else would have to figure the additional area for a fixed keel model. Whenever I figure materials for any kind of job I also add a significant percentage for waste. For painting a relatively small area I'd add a good 15%, at least, bringing it up to 115 sf plus rudder.

Good luck; it's one of those jobs we dread, but afterward it seems like it wasn't so bad after all.

Edited by - on

Stinkpotter
Master Marine Consultant

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Djibouti
9076 Posts

Response Posted - 10/19/2011 : 21:41:19

I forgot to mention, mine was a fin keel. For future discussions, it often helps to tell us your keel (fin or wing) and rig (tall or standard), as well as other characteristics that might influence the responses. You can record these things in the "Signature" in your "Profile", which is what you see in other posts here, below the line--like this one:

Edited by - Stinkpotter on 10/19/2011 21:42:17

Ape-X
Admiral

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USA
662 Posts

Response Posted - 10/20/2011 : 04:54:20

I used one QUART of VC-17 as an all-over thin recoating: We used a 1" sponge type roller, and had my helper hold the can. Dipped the roller directly in the can and immediately closed the lid. No evaporation that way.

Fin Keel, included the rudder.

Edited by - on

dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 10/20/2011 : 06:03:45

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by C255885
 thanks, I looked at the VC 17 but wanted to go with ablative rather than the hard epoxy and the removal thereof in future years.<hr height="1" noshade id="quote"></blockquote id="quote">

I've been using VC-17m on my C25 for over ten years now and although its not listed as an ablative, I've found VC-17m does wear away, especially on the leading edges. Also there isn't any build up to speak of nor any chipping or crackling, just a nice, smooth bottom. With the proper application technique, I can use one quart to single coat the entire boat, double coat the rudder and from the waterline down to about a foot, with a triple coat on the leading edge of the keel.

Some good info here...

[url="http://www.yachtpaint.com/LiteratureCentre/boat-painting-guide-10-usa-eng.pdf"]Interlux Boat Paint Guide[/url]

Edited by - on

JohnP
Master Marine Consultant

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1520 Posts

Response Posted - 10/20/2011 : 09:21:44

I have painted my boat's bottom three times in the 6 years I've owned it. Both times I used 75-80% of a gallon of Pettit Trinidad SR hard paint, including 1 coat all over and an additional coat on the front and sides of the fin keel and on the rudder. I painted blue first, then red over blue, and then blue over red to monitor the wear areas.

Naked gel coat looks different from hard paint which looks different from ablative paint. The first is "white", the second is colored and doesn't rub off on a paper towel, and the third rubs off easily.

The previous owner should also know what's on the bottom.

Edited by - on

glivs
Admiral

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USA
836 Posts

Response Posted - 10/20/2011 : 11:50:23

I am also looking to paint the bottom of our '89 this next spring and have watched this forum for some time regarding the use of a no sand primer. I don't recall anyone yet taking that approach. Other '89ers have tried soda blasting or sanding but I'm going to try the Readi-strip approach and "no sand primer". Currently we have an ablative paint put on by the PO and there is not a lot of buildup. It has lasted six years with only minor touch ups needed, but these past couple of summers the slime buildup has been noticeable (especially post-Irene). The areas where the polyester vinyl bottom are occasionally exposed, e.g. under the cradle pads, are a light grey color and very smooth - but a different feel altogether from the gelcoat on the topsides. Please keep us posted - I'm very interested to learn how you approach your project and what you find. Am also interested if anyone has any experience with the new no copper bottom paints from Pettit.

Edited by - glivs on 10/20/2011 11:54:22

dmpilc
Master Marine Consultant

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USA
4593 Posts

Response Posted - 10/20/2011 : 12:16:36

Last October I repainted the bottom of our C-25, "Recess", after pressure washing and light sanding the existing paint. Sanding the waterline scum and deposits took longer and required more elbow grease. My existing paint was Interlux Ultra, a hard finish paint, and it lasted almost 4 years. The paint I used this time was Interlux Ultra-Kote, very similar, which I got on sale. I like that paint a lot. I put on 2 coats and used less than 1.5 gallons, maybe 1.2 gal. The can feels almost full, so I have a bunch left over for touch-ups. The first coat will use more than subsequent coats. also, I did not paint under the 6 pads and I have a swing keel.

If you are taking all of the bottom paint off, i.e. going down to the gelcoat, many here recommend using one color for the first coat and another color for the second and/or third coat. Then, when the top coat is wearing thin, the contrasting color underneath will show up as a wear indicatior. Also, if you are taking the paint all off, consider applying a good barrier coat before applying the anti-fouling paint. In retrospect, I wish we had gone that extra step.

The main thing is to get a good quality paint that is appropriate for where you will be keeping the boat. Some work better than others in particular geographic areas.

Also, I'm told that ablative paints can be applied over hard finish paints, but not vice versa.

Edit: For the first painting after we bought her, I bought 2 gallons plus a quart. We used almost all of it. for the second painting, as indicated above, I used maybe 1.2 gallons. Perhaps I applied it thinner than the guy who did the first painting. Time will tell.

Edited by - dmpilc on 10/20/2011 12:34:30

dmpilc
Master Marine Consultant

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USA
4593 Posts

Response Posted - 10/20/2011 : 12:33:38

Hey C255885,
In the thread about removing the rudder, you indicated that you dry sail your boat. Are you getting it ready for a wet slip, or an extended sail? If not, why would you go to the trouble to put anti-fouling paint on it?

Edited by - on

WesAllen
Navigator

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USA
222 Posts

Response Posted - 10/20/2011 : 16:43:48

I used just over a gallon and a half of the Micron Extra last winter on my swing keel version. First coat of blue and next two coats of brown. That didn't leave any brown left for touch up. Stinky stuff if your inside use lots of ventilation. (P.S. one coat each day) Easy to put on but prep was where the work is hard and dirty (worth it in my opinion) It took about a week in all.

Edited by - on

pastmember
Master Marine Consultant

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2402 Posts

Response Posted - 10/20/2011 : 17:12:11

I used no sand primer on my '89. I tend to be a little more emphatic about some things than some on this board. If there is any way for VC 17 to meet your needs then you are making a huge mistake if you do not use it. Your remark about worrying about taking an epoxy paint off shows that you have not put the right info together in your thought process. Don is absolutely right, VC17 goes on so thin that it wears away better than the road tar called ablative paint so many are forced to use because of their circumstances. VC17 turns annual bottom painting into a trivial event provided you have pressure washed the bottom when you hauled the boat and only a fool does not pressure wash their hull when they haul their boat.
Back to the no sand prep, first I used a gasoline powered pressure washer to remove years of lime built up over the POs bottom paint, (I am the guy that uses photos), This was the bottom when I bought it

this is what your factory barrier coat looks like, if you screw it up by sanding it will be a tragedy, if your PO already screwed it up his karma is in a world of hurt. BTW this photo was minutes before a 100 mph wind blew the boat on its trailer across the parking lot and almost into the lake, it was very entertaining).

This is what VC17 looks like after 1 season and a power wash, note the places where it has worn off completely.

painting in the spring takes less than an hour

and if nothing else convinces you... if your bottom is shinier than most people's topsides you know you have done the right thing.

Edited by - pastmember on 10/20/2011 17:19:32

Steve Milby
Past Commodore

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USA
5895 Posts

Response Posted - 10/20/2011 : 17:37:33

Gerry, if fresh antifouling hasn't been applied in 6 years, it's likely that the anti-slime properties of the paint have bled out and are no longer effective. That would account for the recent increase in slime.

Also, after 6 years, I'm surprised that any ablative paint remains. The idea of ablatives is that they ablate over time, and that's what keeps the bottom fairly clean. If anything tries to attach to it, the paint dissolves out from under it. I usually put one coat of good quality ablative paint on my boat every year, and it begins to get thin by the end of the summer. That's why it's hard to imagine one application lasting 6 years. I'm wondering if your PO gave you mistaken information about the paint.

The light gray patches under the cradle pads sounds like a barrier coat. If so, I would recommend you not remove it.

You said there is not a lot of buildup of old paint. If so, I would recommend against stripping off the old paint. First, stripping off all old paint is a nasty, dirty, unpleasant job, and it's hard work. You should only have to strip the bottom when the old paint is built up so much that it has started peeling, like the paint on an old wooden-sided house. I would suggest you wet sand the bottom, to smooth the surface, and then apply a fresh coat of antifouling.

Edited by - on

GaryB
Master Marine Consultant

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USA
4303 Posts

Response Posted - 10/20/2011 : 18:38:28

I've owned my boat for 4 years now and the bottom paint was almost new when I bought it. It's been out 2 or 3 times long enough to pressure wash it and then right back in. The last time was Spring 2010. At that time the paint was getting thin but was not completely worn through.

I'm thinking seriously of putting her on the trailer for the first time in December and storing in a covered dry boat stall so I can polish the hull and do various repairs. I'll probably have a bottom job done before going back in next Spring.

Edited by - on

glivs
Admiral

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USA
836 Posts

Response Posted - 10/20/2011 : 19:18:21

Frank...my apologies...should have known you used the no sand primer on your boat.

Steve - I haven't done anything but spot touch up the bottom over those six years in hope that either due to the fall power wash or the nature of the paint it would get thin enough to make removal easy. Each season there are more areas to touch up but none larger than a quarter. The fact that it has lasted so long may attest to our short seasons. IIRC the paint is Micron Extra and is functionally ablative as it comes off readily both in the yard or in the water when you brush against it. I have to bag the rudder before removing it to keep clean. As for stripping....I appreciate your thoughts...I'm not a racer but do want to address a substantial ding in the wing keel where it appears the PO had a close encounter (perhaps cradle) at some point...cannot apply filler without removing existing paint. How eager I am to get her wet in the spring will determine which route I take.

Edited by - glivs on 10/21/2011 07:12:16

OLarryR
Master Marine Consultant

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USA
3440 Posts

Response Posted - 10/21/2011 : 03:22:57

The PO had an ablative paint for approximately 4 years and I got another year out of it before repainting it with Micron Extra, a copolymer that functions similar to an ablative paint. Similarly, I have gotten 5 years out of it and it is due for repainting ...right now.

My boat is in the water year-round and only comes out for an annual pressure wash in the Fall. Last Fall, I noticed there was an increase of slime on the bottom and so I knew the multi-year paint was on it's last legs. Therefore, I had it pressure washed after only 6 months, done this past Spring. This was so I could re-evaluate if I should repaint in the Fall...and I was also keeping an eye thru the years on blisters and if there was an increase, then I was going to consider waterproofing in addition to the repainting with a multi-year paint.

When it was pressure washed this past Spring, the slime was not that bad (well this was only after 6 months since last pressure wash and the winter months when slime buildup would be expected to be low). But during the pressure wash, there was the absence of a blue tint in the water run-off and checking by running my finger on the paint that remained (some past hard paint that was applied many years past), there was no characteristic blue finger and so the ablative paint was completely off. Now some alternate paint colors so they can tell when the most recently applied ablative paint has come off but observing the water run-off from pressure washing and the finger rubbing test is as a good an indicator as well.

Last week, I brought my boat over to a marina that can accomplish the waterproofing after squaring away the blisters and then will repaint with anti-fouling paint. Right now, I am leaning toward repainting with a hard faced paint and then putting probably Micron Extra or another ablative/copolymer paint over it. It is best to always check the specific mfrs instructions regarding prep work necessary and compatibility of paints when repainting. generally, there is no issue when putting a copolymer/ablative paint over a hard faced paint. Some light sanding and that is about it. But if desiring a hard paint to be put over a copolymer or ablative paint...that would probably require removal of the multi-year paint first since the multi-year paints degrade with time and would therefore not be a good base for a hard paint.

Edited by - OLarryR on 10/21/2011 03:27:53

Dave5041
Former Mainsheet Editor

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USA
3758 Posts

Response Posted - 10/22/2011 : 04:33:08

Pettit/West Marine CPP , 3 quarts and one left over for next year. I actually repainted last Spring with with accumulated remains - ugly, but it got me through until I change colors next year. I usually get 2 - 3 years out of a base coat with annual touchups. I get under the rollers by throwing a line around a utility pole, attach to the stern cleats, loosen the safety chain and winch strap, and pull forward a couple of feet. Don't unhitch the trailer with the boat pulled back.

Edited by - on

wegman
1st Mate

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USA
35 Posts

Response Posted - 10/22/2011 : 13:45:00

Frank, I noticed that in your photos (above) of your trailer there was no carpeting on the keel board. My understanding is that carpet serves an important function in that when wet, it provides a lower friction surface. This is useful if the boat needs to be winched in to the V blocks. It also would be useful to have a lower friction surface when using Dave's system (in the previous post) to move the boat a few feet to paint under the rollers.
I have read that some people even go so far as to put soap on the carpet, to reduce friction further. Others with more experience may wish to confirm or discredit the importance of carpet on the keel board.

Edited by - on

pastmember
Master Marine Consultant

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2402 Posts

Response Posted - 10/22/2011 : 15:04:40

Thanks for the tip Jerry, It was the PO that had no carpet, I redid the carpet with special foam padding under it to both drain water away to reduce the osmotic pressure and to add a skosh of conformity to the curves of the hull and keel. I am lucky though, we use a crane that we all have a key to so my keel never slides; and my bearing never get wet! I don't want to hijack this thread so I will put some photos of the carpet upgrade in another thread.

Edited by - pastmember on 10/22/2011 15:12:24

GaryB
Master Marine Consultant

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USA
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Response Posted - 10/22/2011 : 19:35:12

Frank,

What's the name of the special foam padding you use and where do you get it?

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pastmember
Master Marine Consultant

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Response Posted - 10/23/2011 : 13:39:32

I found it among the work area floor mats at Home Depot, I imagine it is a standard product.

Edited by - on

GaryB
Master Marine Consultant

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USA
4303 Posts

Response Posted - 10/23/2011 : 16:22:28

Yeah, I actually have two myself. Front and back doors.

I'll get some fresh ones to install on my trailer before I pull Andiamo in December.

Edited by - GaryB on 10/23/2011 16:22:58

Stinkpotter
Master Marine Consultant

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Djibouti
9076 Posts

Response Posted - 10/23/2011 : 19:05:09

Back to paint... Keep in mind that responses here tend to be divided between fresh water and salt water owners. The differences are significant. Even in either environment, there are differences based on water temperatures, salinity, run-off, invasive species, etc. Local opinions are valuable. And quantities vary substantially between VC-17 and co-polymer/ablative paints.

Edited by - Stinkpotter on 10/23/2011 19:08:19

OLarryR
Master Marine Consultant

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USA
3440 Posts

Response Posted - 10/24/2011 : 03:24:27

One thing to cnsider when going to the boat shows...well ours just ended. I took the time to talk to the paint mfrs that were represented at the Annapolis show and it was quite helpful. I would have to review the notes they and I jiotted down for reference but as I sail in freshwater and slime is the big issue not barnacles, etc growth, the mfrs had other options for me to consider when I repaint with an ablative or copolymer paint this year. Since slime is the main issue, the copper content is really of little importance. It is the anti-slime bio content that is important. So, having the choice of two products both with anti-slime additives, the one with the lower copper content will work fine for freshwater and will be less costly. I jotted down a few addl notes from both Petit and Interlux mfrs. So, it is a good idea when browsing these sailboat shows to stop by and discuss your specific sailing area and what they reoommend. Of course, it is always a good idea to check with those sailboat neighbors at your marina and see what has worked for them or go by past experience that has worked for yourself. In my case, I know Micron Extra has worked well for my boat in freshwater but I now know there are other options that may be equally as good, maybe better and at same time less costly.

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