Bottom Painting Question

rh320

Member
Mar 2, 2018
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good evening, all. This is my first offseason with a bigger boat that stays in a wet slip. My boat was hauled out in November and pressure washed and blocked for winter. I’m now ready to get it prepared for its splashing and I have a question about bottom painting as this is new to me.

I noticed that some of the bottom paint has flaked off. I don’t know if that was a result of use and age or pressure washing or a combination of both but regardless some spots are missing paint and exposing a different color. Not sure if that’s like a base primer or it was a different color from a previous year paint job. It’s gray if that matters.

So my question is how do I know what type of paint to use. I’m assuming it’s an ablative paint since parts are flaking off? But are there different types of ablative paint? How would I know which to choose.

Also, do I need to repaint the entire bottom or can I spot paint the areas where it has flaked off? Do I need a to apply a primer in those areas?

Any help would be greatly appreciated!

Ryan
 
tiara in the snow 01.JPG
Bottom paint should not flake off. Ablative paints wear off evenly when properly applied. It is really hard to know what you have without seeing the bottom or maintenance records. Paint failures like you describe typically result from the surface not being properly prepared prior to painting. Painting over poorly prepared surfaces will be an annual exercise in frustration. The best solution is to strip the bottom and apply a paint suited to your local conditions while following the paint manufacturer's instructions.
 
View attachment 66577 Bottom paint should not flake off. Ablative paints wear off evenly when properly applied. It is really hard to know what you have without seeing the bottom or maintenance records. Paint failures like you describe typically result from the surface not being properly prepared prior to painting. Painting over poorly prepared surfaces will be an annual exercise in frustration. The best solution is to strip the bottom and apply a paint suited to your local conditions while following the paint manufacturer's instructions.
I bought the boat last year so I don't know anything about previous paint jobs. I assumed I might have to strip the old paint and reapply to avoid the annual frustrations you mentioned.
 
When in doubt, a hard ablative can be painted over any previously applied paint. Different color under coat is done with ablative paints as the “tell” when the paint has worn away.

Quickest solution is a maroon scotchbrite pad, scuff the areas, wipe down with Dewax, and paint on 2 coats of modified ablative in the same color. Done....
 
tiara in the snow 01.JPG
The type of paint varies by region and water conditions. Local service people will know what works best for your location. Bottom paint lasts 2-3 years in many locations. Power washing is typically done when you lay up a boat or pull it for annual maintenance. It does not cause paint to flake. Our boat has three year old paint on it right now. I'll post a pic of its condition so you can see what a proper paint job looks like.
 
tiara in the snow 01.JPG

IMG_3574.JPG

Three year old bottom paint after power washing. It takes 1 quart of ablative paint to cover the bottom of a previously painted 32 foot Tiara.
 
When in doubt, a hard ablative can be painted over any previously applied paint. Different color under coat is done with ablative paints as the “tell” when the paint has worn away.

Quickest solution is a maroon scotchbrite pad, scuff the areas, wipe down with Dewax, and paint on 2 coats of modified ablative in the same color. Done....

Thanks for the reply. So you are saying regardless of what paint was previously used I can lightly sand and apply a modified ablative?
 
tiara in the snow 01.JPG
Nice boat. Always loved tiaras!!
Thanks. You need to keep in mind that paint compatibility is only part of the issue you are facing. If the old paint is flaking off, your newly applied compatible paint will fail when the paint it is adhered to flakes off again. Best to start with a freshly prepared total bottom so you don't have this problem every year. Unless ordered with no paint, Tiara boats come from the factory with one coat of paint properly applied, and more paint in unopened cans to be applied before the boat is sold to a customer.
 
View attachment 66582
Thanks. You need to keep in mind that paint compatibility is only part of the issue you are facing. If the old paint is flaking off, your newly applied compatible paint will fail when the paint it is adhered to flakes off again. Best to start with a freshly prepared total bottom so you don't have this problem every year. Unless ordered with no paint, Tiara boats come from the factory with one coat of paint properly applied, and more paint in unopened cans to be applied before the boat is sold to a customer.

Yeah I was afraid there was not going to be an easy way out so I was prepared to hear I may have to go back to the beginning. I am in construction so I have many orbital sanders and dust extractors so can I use them to sand as much back to the original as possible or do I need to hire a soda blaster? Also, do I need a primer coat?
 
If the bottom paint flakes off it is usually do to poor prep before applying the bottom paint to the hull. On my 260da I had to have the bottom paint scraped and sanded and a barrier coat put down before the paint. On my 340sda the PO had the bottom soda blasted and prepped with and interlux barrier coat in grey before putting on the ablative. Never had flaking and you could see the grey when it wore down. I typically get 2 to 3 years but play it safe when I start seeing the grey.

-Kevin
 
If the bottom paint flakes off it is usually do to poor prep before applying the bottom paint to the hull. On my 260da I had to have the bottom paint scraped and sanded and a barrier coat put down before the paint. On my 340sda the PO had the bottom soda blasted and prepped with and interlux barrier coat in grey before putting on the ablative. Never had flaking and you could see the grey when it wore down. I typically get 2 to 3 years but play it safe when I start seeing the grey.

-Kevin

Thanks for the reply! So I guess it's possible the grey that I see in random spots is a barrier coat? If not do I need a barrier coat? Can I use an orbital sander to get back to square on instead of paying someone to soda blast?
 
Thanks for the reply! So I guess it's possible the grey that I see in random spots is a barrier coat? If not do I need a barrier coat? Can I use an orbital sander to get back to square on instead of paying someone to soda blast?

All depends on how long you want to keep the boat. If you're planning on keeping it a while a full strip and then barrier and bottom paint will give you less aggravations and maybe even a little bit of performance. If you're only keeping it a few years this cost may be prohibitive compared to quick annual touch ups.

Without seeing it it hard to judge but a touch up might be all you need with some good sanding before paint.

With your size boat I don't think I would want to sand it myself not to mention spending all that time in a tyvec suit and respirator.

-Kevin
 
All depends on how long you want to keep the boat. If you're planning on keeping it a while a full strip and then barrier and bottom paint will give you less aggravations and maybe even a little bit of performance. If you're only keeping it a few years this cost may be prohibitive compared to quick annual touch ups.

Without seeing it it hard to judge but a touch up might be all you need with some good sanding before paint.

With your size boat I don't think I would want to sand it myself not to mention spending all that time in a tyvec suit and respirator.

-Kevin

Ideally I'd like for it to sell and upgrade to a 400 da this year or next year at the latest. So I'd prefer to put less money into it than need be which is why I would consider doing it myself.
 
tiara in the snow 01.JPG
If you don't mind doing a really crappy job, then do the prep work and painting yourself. I've only painted a bottom once and that was enough. Various boats I've owned have been sand blasted, walnut shell blasted and soda blasted. Soda would be my preference because it is the easiest on the hull of the three. Each will expose or produce voids that must be repaired. One of the best paint systems I've used is VC paint. The barrier coat is called VC Tar. This is followed by VC Teflon. I used that on a new 1986 Week Ender that was poorly painted by the selling dealer who went out of business. The VC system held up very well in Lake Michigan and looked great for the several years that I owned the boat. If you sell your boat in a year or two, the surveyor will note the quality of the bottom paint work. Cutting corners will be documented and the buyer will likely ask for a price concession to have the job done properly. I generally do things once and enjoy the outcome while I own the boat. No one ever said boat own ship is inexpensive.
 
What percent of the bottom area is flaking?
If you are talking about 5-10%, scotchbrite and touch up with modified ablative like Pettit Hydrocoat.
If a significant percent of the bottom area is affected, then sand, use a tie coat, and repaint.
I have done all my boats, and plenty for friends. It is simple work. Tedious, but simple. They all looked perfect afterwards, and none ever failed.
 
Thanks for the reply. So you are saying regardless of what paint was previously used I can lightly sand and apply a modified ablative?
That varies by manufacturer, but for the most part, yes.
 
View attachment 66583 If you don't mind doing a really crappy job, then do the prep work and painting yourself. I've only painted a bottom once and that was enough. Various boats I've owned have been sand blasted, walnut shell blasted and soda blasted. Soda would be my preference because it is the easiest on the hull of the three. Each will expose or produce voids that must be repaired. One of the best paint systems I've used is VC paint. The barrier coat is called VC Tar. This is followed by VC Teflon. I used that on a new 1986 Week Ender that was poorly painted by the selling dealer who went out of business. The VC system held up very well in Lake Michigan and looked great for the several years that I owned the boat. If you sell your boat in a year or two, the surveyor will note the quality of the bottom paint work. Cutting corners will be documented and the buyer will likely ask for a price concession to have the job done properly. I generally do things once and enjoy the outcome while I own the boat. No one ever said boat own ship is inexpensive.

Well I restore old houses so I'm no stranger to lengthy and tedious prep work and painting old plaster walls and trim so I feel up to it. Most marine "professionals" in my area are not very professional at all. I probably will pay to have the hull blasted instead of my sanding though. I've read soda would be the most preferable as you mentioned.
 
What percent of the bottom area is flaking?
If you are talking about 5-10%, scotchbrite and touch up with modified ablative like Pettit Hydrocoat.
If a significant percent of the bottom area is affected, then sand, use a tie coat, and repaint.
I have done all my boats, and plenty for friends. It is simple work. Tedious, but simple. They all looked perfect afterwards, and none ever failed.

Yeah 5% is probably a pretty accurate percentage of the flaking. It's definitely way less than 10%. I bought it last year and told the broker who I bought it from that I wanted the bottom repainted because it had very little flaking. Well it's flaking off in those exact same areas but even more so now. That's why I'm hesitant to pay someone to do it again.
 
If you really want to get rid of the boat within the year I would just scuff up the flaking areas and touch them up.

If you do blast it I would go with a minimum of 2 coats of interprotect barrier followed by another 2 ablative coats.

Kevin
 

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