My first hull job. Please weigh in.

[TheLastUnicorn]

(Forgive me if I sound ignorant.... I am.). This is my first time doing a hull. My boat is older and has not had an overhaul in a long time, as far as I can tell. I’ve been doing a bit of research into materials, processes and techniques. Rather than take the easy way out and rush the boat into the water, I have decided to put the extra work in, sand the entire hull down too the gelcoat below the waterline and apply a barrier coat. I am completely inexperienced and the project is happening in my front yard, totally unsupervised, so I could really use some guidance.

1) Between the two options of A: giving her a light sanding and then just re-painting her with bottom paint or B: Putting in all of the additional labor and expense of getting her stripped to the gelcoat, two coats of barrier paint, a tracer coat of bottom paint and two final coats of bottom paint (IS THIS FOR REAL???), is it worth it??

I’m told that taking the time to get down to the gelcoat and do the extra coats of barrier paint will pay off by basically never really having to do a major hull job again, as long as I stay on top of my regular maintenance. I’m told I am giving myself insurance against a waterlogged hull. My future annual maintainance will consist of a light spot-sanding and touch-up.

Its A LOT of work. Fortunately, my boat is only 20’, but handling that Festool sander is like wrestling an alligator (I imagine). I am a slight, but strong, woman. I can get through it, but first, I want to make sure I’m not being stupid or doing anything that is not going to pay off in the end.

2). I have shopped paints and primers at West Marine, but even in my short span of boat ownership, I recognize that they do not have good pricing. Any recommendations of good places to shop online to save? Products that are the best bang for your buck?

3). Take a look at my photos. I spent a good number of hours scraping and am now sanding with 40grit. I’ve made it down to gelcoat. I’m a little squeamish.... Have I sanded far enough?? I imagine I want to NOT sand through the gelcoat... is that even a thing?? The guy at West Marine warned me to make sure I get ALL of the paint off and then clean it well with acetone.

4) My boat has a double keel. Its clear the previous owner didn’t address the bottom of the keels where they sit on the skis in quite some time, if ever. My keels are cast iron and fiberglassed over. How important is it that I get under there and if so, any tricks? I don’t have boat stands but I do have house jacks and all manner of bottle jacks...

Any advice? Anything I am not thinking of?

[Don C L]

Is that a Signet 20?
At first blush your hull looks fine. First, did you have blisters on the hull? It doesn't look like it and the older boats rarely do. The barrier coats are usually needed for those who have some issues, like blisters in the gel coat or initial layers. If you have no issues, the barrier coat is nice, but not required IMO, but I am not a professional in the field, just a fellow boatowner. On my own boat, also older, I have no issues like those and it has never been taken down to the gelcoat for a barrier coat.
Cruisers & Sailing Forums - Don C L's Album: 1962 Columbia 29 MK 1, hull #37 - Picture
Last time I took it down to its first coat, added two coats of the hard stuff and one of ablative. That was four years ago, my boat is not cleaned every month and it was just cleaned the other day and the hull was fine. The boat was built in '62.
btw yes, you will want to get under the keels to put a couple layers of paint or else you'll be dragging a beard of growth around with you.
Is there any indication of damage to the keels and/or rust coming from inside the keel(s)?
I feel your pain! which is why I try to avoid any more than necessary on these types of things
Welcome aboard by the way!

[JBP]

I'm with Don, if you don't have severe blister problems in over 50 years, there isn't really any point to doing all the extra work for a barrier coat. Especially since your boat is small and on a trailer so you can let it dry out in the off season.

TotalBoat from Jamestown Distributors is my new favorite for less expensive bottom paint.

[Pete7]

If your not sure about sanding it, then use one of the chemical paint strippers for GRP. They are not great and need work but safer than sanding. I did a 24 for GRP Rib with £75 of stripper from International paints. Needs cool weather ideally so it doesn't dry out and covering with cling film once applied for the same reason. Do a section, cover and move onto the next section. Once the paint has softened you then use an ordinary paint scraper. PPE needed as it gets everywhere, and a ground sheet to collect the old paint. Multiple coats of stripper will probably be needed depending on the thickness and number of layers. Finally a lot of water to wash it all clean.

It was a god forsaken job, but sanding would have been much worse. Took four days graft to strip and then repaint a 24 ft boat on the trailer. Chock the trailer properly and then the boat so nothing moves whilst you are underneath.

Pete

[TheLastUnicorn]

Don, she’s a 1971 Vivacity 20.

I see nothing that looks like I would call it a “blister”. There is a bit of “crazing” bus seems to be mostly limited to the keels. I uploaded another photo so you can see what I am talking about there.

I have learned about “ablative”; what do you mean by “the hard stuff”?

I have taken apx 10% of the hull below the waterline down to the gelcoat at this point.... Have I screwed myself? Can I abort mission on the barrier paint and instead just sand off down to a smooth layer and repaint? Do I need to do something additional to the areas that are already taken down to the gelcoat?

Having spent a good number of hours underneath her, I see nothing on the hull or keels that I would call an “indication of damage” and certainly no rust. Just the crazing, as mentioned.

[Don C L]

Nah, you haven't screwed yourself. If the paint coverage was good, the original paint has good adhesion, then it was probably prepared well and is fine. For the area that you have taken down, and for any other areas you are not sure of, I'd apply a primer intended for the paint you get. The crazing is common to gelcoat and does not indicate any problems. It SOUNDS like you can sand off most until you get to the last layer and if all the adhesion of the original paint is good then it should be fine to cover with new layers. That's one person's humble opinion.
Those Vivacities look like nice little boats! I sailed a Signet 20 down the California coast once with a buddy. 240 nm in 48 hours non-stop
BTW, here is an article about hard vs. ablative paint.
https://www.bottompaintstore.com/blo...-bottom-paint/
The only reason I put ablative over my hard stuff was I had some left over from somebody else. I figured, why let it go to waste?

[TheLastUnicorn]

AAAHHHHHH! What a relief! TThanks for saving me from a time-consuming, back-breaking and expensive mistake!

I’m researching Interlux products. That’s the product line I am leaning toward, for no particular reason other than they do a great job of making instructional material accessible to the newbie. I’m looking at at the Interlux Watertite 2-part epoxy for the areas where I sanded down too much and any areas that look cracked or crazed. I’ll follow this with one of the anti-fouling paints, 2-3 coats for the waterline and one of the topside paints after. They have som many anti-fouling paints and top-side paints that I will need to do some more research into which particular product is best and most cost effective... But I figure I have time since I definitely have at least a few more prep sessions before I get to painting!

I’m so looking forward to the adventures. I have a 13yo step-daughter who is the same kind of game chick I am and we have big plans to find places where we can sail off and camp; hopefully catch some fish to cook and eat and do an overnight or two in the cozy cabin.

Once I’m done researching paint and my various other refitting projects, I’m looking forward to planning some sailboat exploration and camping.

I was warned by the old WWII merchant marine who sold her to me “She’s NOT fast”. I’m all set with speed. II’ve been running fast horses my whole life and I’m ready to slow it down, but I’m definitely looking forward to getting out there... and not coming back til I am good and ready!

[Don C L]

Interlux is fine and the watertite is fine as a filler, but you won't need much, I bet the 1/2 quart will leave you with leftovers. If you have any divets or holes to fill anywhere else on the boat, have those prepped and ready to fill too, just in case. Make sure you are ready to fill all the areas in under 10 minutes, so smooth it on fast, you'll sand it smooth later. Maybe your step-daughter can help you! Sounds like a great adventurous plan you have! Best of luck!

[Greg Mason]

Unicorn, it's all relative. I had my 40' hull soda blasted last year to the gel coat because I had no bottom paint history and it was flaking. Did the Inter protect 2000 system in 2 different colours, (so I could tell) and Micron CSC for paint. Hauled last week and the lift guys were marvelling at the cleanliness of the hull. Was very easy this year, zincs and one coat and splash.

[AndyEss]

Looks like you are progressing well with your hull work. What did you decide about the rub rail repairs?
Try to involve your 13 yo stepdaughter with your boat work, it should be a good bonding experience. I guess I would not have her involved with bottom paint sanding or working with solvents/epoxy, even with PPE. Have her clean and prep cockpit and cabin interior?
Your plans for camping and fishing with her sound excellent.

[LouK]

My guess is that a bottom is a very unsuccessful way to bond with a teenager. That said, I offer the following comments having recently finished my 2nd bottom job.

-40 grit is much too aggressive & you may wind up going deeper than you’d like.
-Given the cost of Interprotect & the age of your boat, if the Gelcoat does not have blisters (flat bubbles), pock marks or pinholes at this stage of life, I personally would forgoe the barrier coat.

- another disadvantage of 40 grit is that it becomes all to easy to put a gouge in your bottom, something you’ll need to by more expensive chemicals to fill

- I’ve used micron csc for many years & have gottten decent service in both Long Island Sound & now in the Chesapeake. You’ll have to touch up the second year but as far as I can tell it seems to be as good if not better than most.

- WM is not cheap but will price match Defenders or other on-line pricing, give it a shot.

Good luck, it’s miserable work but you’ll be oh so happy when’s it’s over.

[Tusitala]

Good morning,

Yes, that's a hard nasty job but you're going about it the correct way. 60 grit would be the most aggressive grit I used, my standard go to is 80. But for this I'd use the 60.

While blistering may not be an issue with the vintage of your boat excessive build up over the years could be, I can't really tell from the photos if the paint remaining on the hull is in good condition or is cracked and peeling and not firmly attached. If it's in reasonable shape it would be good if you knew what brand and type the last coating of bottom paint applied was for overcoating compatibility. The areas you have sanded to bare gelcoat look fine. I would apply a couple of coats of International Interprotect 2000e over the bare gelcoat. It's not really more $$ than any of the primers meant to be used below the waterline and pretty much sticks to anything. I use it under most paints, interior, exterior and below the waterline. It has the added benefit of not sanding between coats or before applying the antifouling. It also has a longer potlife than the similar products from competing manufacturers. If you have a reasonable sunny day you could get 2-3 coats of it on without sanding between coats, and overcoat with the bottom paint of your choice also w/o having to sand the next day. You can go up to 6 months from applying Interprotect to overcoating with bottom paint without sanding it.

Definitely use a multiseason ablative paint. most other types of paint, like epoxy or vinyl based, need sanding every season to overcoat. If you do decide to strip the rest of the old paint off your hull apply a different color for the 1st coat, say black, followed by the color you desire for the finish coat. that way it's really easy to see when the finish is getting thin. The current trend is for water based ablative. I've used stuff from a bunch of manufacturers and it seems good, very easy to work with. Talk to people where you plan to keep your boat and see what's working for them

As for suppliers, shop around, see what works for you with shipping included. Defender is a good source, as are Jamestown Distributors and Hamilton Marine. West Marine will price match against most, but no longer with Defender .

Sorry to get so long winded. Good luck! Think of all the money you're saving on gym fees!


Pat

[skipmac]

Well, here's my two cents worth.

1. Stripping ALL the paint? The reason for this is because some paints are not compatible so you paint some new paint on top of old and the new may not stick or might even peel off.

2. Ablative or hard paint? Ablative as the name implies, is soft and designed to slowly erode away preventing the slime and barnacles from growing. Hard paint is, well hard, stays on the boat and prevents growth by leaching the active ingredient (usually copper). Hard paints generally aren't designed to be hauled and dry out so if you plan to keep the boat on the trailer most of the time you will want an ablative.

3. Gel coat and barrier. Again if you leave the boat on the trailer most of the time then probably won't need a barrier coat. If you keep the boat in the water for the season and only haul in the fall then I would maybe consider a barrier especially if you've sanded through the gel coat and exposed the glass fiber beneath.

4. Pertaining to #3, 40 grit may be a bit too aggressive but can make the job go a lot faster. Maybe 40 for the initial but quickly switch to higher numbers as soon as you see any gel coat.

[MartinR]

If there are no blisters, there is no reason to take the paint down to the gelcoat, like the other posts said.

I would never sand down antifouling. There are antifouling removers available, that do this without risking your health. Apply - wait - scrape off. Then you can sand the gelcoat lightly IF you want to apply a barrier coat. The gelcoat itself is in most cases good enough.

[Tusitala]

Like I said, if there's too many layers of paint and it's in bad shape it needs to come off before anything else will adhere. you can't just keep putting paint over cracked peeling paint without getting more cracked peeling paint, and I can't tell the condition from the photos.

I've seen those antifouling removers used, they don't work very well and make a huge sticky mess. The Festool sander she's using is an excellent dustless sanding system.
I'm not talking about using the Interprotect as a barrier coat in the event of no blisters, it's an excellent below the waterline primer that adheres very well and bottom paints adhere to it excellently. I've seen too many patchy failed bottom jobs to not prime over bare glass or gelcoat. A quart costs $40.

Pat