How to paint
a boat

... Sanding to remove varnish on large areas is not recommended; use chemicals or a heat gun. ...

The heat gun is a great idea, especially for long flat runs. I caution against waiting for the varnish to bubble though. Not very long after bubbling is burning, and if it is your first time, you have a large chance of burning the wood. (If you think your moisture-blackened mahogany looks bad now, try charring it.) I recommend holding the heat gun in one hand, and the scraper in the other. Warm the varnish over a 1 foot area and keep test scraping every 15 seconds. You will feel the varnish soften, long before it bubbles. As it gets warm enough, it will peel off easily with a soft rubbery texture. The older the varnish, the more heat required. Keep the heat gun moving. Don't wait for all of the surface to bubble. Just a few bubbles indicates very soft varnish - scrape it off, and heat what's left. Use a sharp scraper. If the scraper doesn't take nice paper-thin curls of unheated varnish, your scraper is too dull. If the scraper tears at the bare wood, reverse direction, scrape the other way. Always scrape with the grain. ...

Heat gun and 1" red devil scraper to remove varnish. Soften the varnish and it scrapes right off. Follow with light sanding to smooth out. Make sure that you keep a honing stone close at hand and use it frequently to keep the blade very sharp.

Make a "tack rag" to use after sanding and wiping, just before varnishing:
Take a cotton cloth, dip it in warm water, wring out, sprinkle with turpentine, rub gently, shake out excess, sprinkle with a little varnish, wring out, shake out excess, let cloth dry for half hour.
Store in a closed container.
Renew by sprinkling with water and a few drops of turpentine and varnish.

• Varnish on warm, mostly windless days.
• Prepare surface well. Wipe with a "tack rag".
• Don't stir or shake the can.
• First coat should be thinned.
• Work from unfinished area to finished area.
• Use as few strokes as possible.
• Stroke in one direction.
• Don't apply too heavy; it will sag or run.
• Sand lightly between coats, and wipe with a "tack rag".

... I went to a Behr spar varnish - 3 coats on the exterior teak, two on the interior. Looks great and has held up well. About every three months I lightly sand with one of those foam sandpaper pads and reapply - it takes me about two hours total. I know that to some of you this sounds like a lot of work, but it really is not - I guarantee you that I am one of the laziest boat guys at the marina. I learned my lesson in choice of brushes, though. At first I was using those 69 cent throwaways, bu the varnish looks a thousand times better when I use a 7 dollar top of the line brush. Only trouble is the cleaning afterwards.

I use the clear two-part awlgrip polyurethane for varnishing so I often need small batches from larger containers. It makes a long lasting, hard surface brightwork job with just 3 coats, but it doesn't go well over conventional varnish - it has a tendency to bubble. It may not look as good as a fresh conventional varnish job but averaged over the 2 years (or more) I go between refinishing, the AVERAGE appearance over the period is far superior.

The polyurethane mixing ratios are usually not 1:1 so you need to take a tongue depressor type stirrer and mark the depth on it that you think you need - (which can only come from experience) - with a ball point pen. Divide the space below it with a second line in the ratio of the mix, and add a third line above it for the 10% or ?% of brushing thinner that you need. Since it always runs out when you have just a little more to do, the extra % from the thinner will get you through the job (Yeah, right).

In really hot weather I give the mix a head start by cooling the components in the refrigerator before dispensing, and avoid leaving the mix in the sun while using it.

Pour each of the components in slowly to avoid bubbles so each reaches the next mark on the stirrer held vertically in your mixing pail. Have paper towels handy and wipe the screw tops and caps very thoroughly before replacing them. Then stir gently but thoroughly. The manufacturers say to wait 15 minutes after mixing before using and although I usually do this, however I have not had any problems when I skipped it.

When painting with a brush, draw paint from one side of the container, but wipe the brush out on the other side so the bubbles have to traverse the width before getting to your brush.

• Hard finishes last longer, but are more susceptible to cracking from movement, and more likely to lose adhesion if dampness gets under. Soft finishes are beautiful and flexible and more tolerant of movement and dampness, but wear more easily and are more vulnerable to UV and frost.
• Two-part products: hardest and toughest finishes, but hard to work with. One-part polyurethanes: tough finish and easy to apply, but require many coats, and peel off from dampness. Synthetics (Cetol, WoodPro, etc) are easy to use, but require many coats and often impose their own color. Modern traditional varnishes (Epifanes, etc) are easy to apply and build well. True traditional varnishes are soft and easily damaged. Oil finishes are easy to apply but don't build (so don't last) and often alter the color of the wood.
  
  
• Always wet-sand; less messy, and won't get floating duct landing on wet varnish later.
  
  
• Within reason, quantity and frequency of applications are more important than quality. Build thickness; don't worry about perfection.
  
  
• In general, don't try to keep horizontal surfaces varnished; traffic, sun and damp abuse them.
  
  
• Aim for 9 or 10 coats. Lots of thinner in the first coats. Wet-sand between sets of three coats.
  
  
• A quick coat at the end of the season protects during the off-season.
  
  
• Varnish while in the water: little dust around. Avoid windy days. Avoid very hot days (if you can't, thin even top coats). Don't apply in damp air.
  
  
• Do the job quickly, using a reasonably big brush, keeping a wet edge.
  
  
• Keep air out of the container before closing it up. Maybe add well-cleaned pebbles to displace air.

... Teak decks require continual maintenance to keep from developing problems. You need to keep a close eye on the caulking on a routine basis, they should be rinsed down with salt water as often as possible, daily is best, twice a day even better. If areas around the edges of the boards or around bungs seem to stay a bit wet longer than the surrounding areas (dark spots), then a problem exists in that area and you need to take care of it, quickly. etc ... etc ... etc ... They need to be washed from time to time to keep the wood doing what it does best, just don't use a scrubbing brush ... They need sanding generally once a year, maybe every other year, depending on how you want them to look, etc ... Luckily, most people learn very quickly that trying to "finish" them is more than just a waste of time, so they let them "age" naturally, but that does not eliminate the required maintenance ... On the other side of the coin, for all that attention / effort / sweating, you will end up doing, you will have the most beautiful decks around ... Just don't walk on them in bare feet in the hot summer sun, unless you just rinsed them down with salt water ... :-)

Solid teak decks only need oil when you are trying to sell your boat and want to impress the uninitiated. Otherwise they should be allowed to get that grey weathered look that only requires a daily wash with salt water for maintenance. Veneer teak over FG may be another question.

There's a problem with not oiling: When you leave teak decks exposed to the sun for years on end, without oiling them, the natural oils in the teak start to dry out. Eventually, enough oil is lost to cause the wood to shrink and crack. The soft pulp in the grain washes away and you are left with ridges and cracks. There is a limit to how much sanding you can do to smooth out the ruts. Replacing teak that has been worn and sanded too thin is a very costly option. When the teak planks shrink, it opens up gaps in the black caulking between the planks. Fresh water can settle here, and eventually find its way under the planking. You know what follows.

You don't have to oil very often, but you shouldn't ignore it altogether. Also avoid washing teak decks with any soap that contains lye. The lye will eat away the soft pulp. Don't use a stiff brush to scrub the teak as it too will destroy the soft pulp. The best way to avoid these problems is to avoid having a boat with teak decks.

I have found that the white oxidized layer that develops on teak exposed to the sun for long periods protects the wood underneath just like the oxide on exposed aluminum. I don't believe that the natural oils are lost because you can take an old bleached piece of teak and sand off the oxidized layer which is about 1/1000 inch thick and the wood underneath is like new.

This is based on personal experience, not a scientific test, and I will retract my position if proved wrong. Adding "teak" oil is only a very temporary change since the surface oil rapidly evaporates if exposed to sun and the natural bleached look returns. Teak is so dense that not only are the natural oils retained but added oil has little chance of penetrating, and if it does, then it is into cavities from which it will just as easily evaporate in the sun. I agree about avoiding all types of chemicals or soaps. If you really have to clean the surface, I use a low pressure, pressure washer with plain water.

I like the rough finish produced by the softer wood escaping from between the harder ridges - it is the ultimate non-skid surface - and I think it is a crime to keep sanding the hard ridges down to match the soft, to retain a smooth surface.

Wash your [teak] deck with saltwater and dishwashing liquid ... wood doesn't like fresh water. I leave my deck bare ... oil will only darken the wood and collect dirt ... and dark wood will get too hot to walk on barefoot in the summer.

• Oil on exterior teak turns black.
  
  
• Teak oil doesn't keep in storage.
  
  
• Teak oil can rarely be found/purchased outside USA.
  
  
• Cover exterior teak with 8-10 light coats of varnish, topped by silver-gray paint.

> We have way too much exterior teak that we don't want to continue trying to maintain during the cruise. ...

If you want nice, shiny teak, then sand and prep it, build up LOTS of coats of fresh varnish, then apply one coat of WHITE paint or undercoat over it, protecting the base from ultraviolet degradation. When doing normal maintenance you would sand the first coat of old varnish off, anyway, so there IS NO ADDITIONAL WORK involved. When it's time to "show off", sand the white stuff off with 180 grit, apply a "shine coat" of varnish, and accept the compliments. Then, splash on another coat of white "cover coat" until you feel compelled to flaunt your brightwork again. The white looks like it belongs there (for most boats with basic white trim).

[Re: adding more coats of Armada every year:]

The trick is to keep a sufficient thickness of Armada on to avoid exposing the wood.

We put ten coats on initially and this has held up very well for the past three years except where it was rubbed off by some object such as a piling. (we have no rub rail yet)

Armada slowly disintegrates in the sun. Adding more is simply a matter of washing with a mild Scotch Brite and water, then brushing on new Armada. We have had no adhesion problems, overcoating has been trouble free.

... The hard part is blending the new with the old to avoid a blotchy appearance. I would guess, in Florida at least, three coats a year would keep up.

... in my final prep after sanding, I first wiped the teak with regular household bleach (which brought the color out beautifully), let dry in the sun, then prior to the application of the finish itself, did one last wipedown with acetone and fifteen minutes or so later applied the Armada.

Varnish is absolutely beautiful but Sikkins Cetol looks great and is far less labor intensive. After 3 initial coats 24 hours apart, one coat per year is all you need. Approx $25/qt. but goes a long way. Practical Sailor gave it a rating of number one for looks and durability a couple of years ago but I'm not sure if its rating has changed. ...

Cetol is really easy to use and lasts very well. On my 72MOI41 I applied five coats of cetol and 5 coats of cetol gloss over a year ago. It still looks like I did it yesterday. Including all the teak in the sun every day. In warm weather you can apply 2-3 coats of cetol a day. I've used cetol on several boats and have never had a problem. One trick, frequently stir the cetol (not gloss) when applying. It won't look orange when you're done.

If you put finish on grey teak it will turn black. You need to get rid of the grey; either sand it or use a teak cleaner (two-part cleaner is best, but is harsh and hard on the teak. It will eat out the soft grain, requiring you to sand a bunch anyway).

My opinion is: Cetol, Cetol, Cetol, or if you like, Armada. The new Cetol Light has done away with the orange coloration. Cetol (or Armada) simply can't be beat for overall value: price/performance/prep required/maintenance/quality (ie protection)/looks.

Cetol is the way to go. Try ammonia to get the gray out. Easier on the teak than the two-part commercial cleaners and it won't stain the FRP as you drip it everywhere.

We have some really high end teak furniture on the patio which has been discolored by grit grime and dirt. While not a boat situation, nevertheless I will tell you what did the clean up and restore trick for us. On bare teak! Ready? Windex! Wet it down first with water, then then spray with Windex and brush. Rinse off. The effect should be immediate. We follow this with one of the standard teak treatments.
[Windex contains ammonia; just buying ammonia probably is cheaper.]

Put down 4 coats of Cetol Marine, then 3 coats of Cetol Gloss, allowing 24 hours between coats. No sanding between coats; wipe with mineral spirits to clean before applying next coat.

Each year, sand lightly with 220-grit, then apply a fresh coat of Cetol Gloss.

There is a known chemical incompatibility between CETOL and Boat Life 2-part polysulfide caulk. The CETOL when applied over the caulk eventually breaks it down. You end up with a sticky mess, the caulk "bubbling" out of the seams like tar on an old ship. Heat (hot days) seems to accelerate the problem.

When I bought my M-383 last October, her Cetoled teak was a mess. About 50% was peeled off and the rest was cracked, brown and dull, a good candidate for a "before-and-after" case study. The previous owner advised me to power-wash off the remainder, which is one of the advantages of Sikems by Cetol.

That, right away, raised a red flag. That told me that #1 the adhesion was poor, and #2 power-washing, if not done carefully, with just the right pressure, can scour out the soft teak low, and leave the hard grain high, requiring you to sand the high, hard grain down to the level of the low. Every time you do this with the Cetol product, which appears to be quite often, you wind up with a lot of thin teak, which was my case, and my boat is only 18 years old.

I chose the heat gun method of removal as least damaging to the teak and, I must say, the Sikems came off rather easily, which, in my opinion, was another nail in its coffin.

The directions say five coats, minimum if you're starting from scratch. Sounds like a lot but, you can re-coat after one hour and you don't have to sand for up to 24 hours so, those coats can go on really fast. For me, it took three days to do six coats. That was in October, when the days are getting pretty short.

Hints:

#1 If outside, on bare wood, don't apply in the morning before the sun heats up the wood or else the air inside the wood will expand and create a mass of tiny bubbles on the surface. This stops after 3 or 4 coats. It's best to apply after the sun has reached its zenith when the wood starts to cool down and the air inside the wood is contracting. "Double-coating" within two hours of sundown will result in a cloudy surface.

#2 Round off all sharp edges as Bristol Finish tends to pull away from sharp corners. Or, you can lay an extra brush stroke or two, let it dry for a couple of seconds and go back and finish applying to the adjacent flat surface. Remember, a generously radiused corner will reflect a wider high-light than a sharp one and be more resistant to wear and nicks. Looks professional too.

A hint of how tough this catalyzed, acrylic-urethane is, is in the removal of accidental drips beyond the masking tape. I've tried acetone, paint remover, easy-off, and shaving with a razor-blade. It's very hard to do without damaging the gel-coat. (I'll try heat next.) It's very important to avoid drips or wipe them off immediately.

#3 Occasional "fish-eyes" must be sanded and built up to the surrounding level. Its high surface tension must, also, give it its remarkable leveling and high gloss qualities.

I told myself, 'If I'm going to put in this much effort, I'm going to use the best looking, most durable product with the least maintenance out there because, at my age and this quantity of teak, I'm going to do this just once.' (I really can't knock Sikems. The condition and the huge amount of teak may have lowered the price of the boat.)

#4 Use a foam brush for the final coats, for you can put on a thin, smooth coat on a hot surface without re-stroking back over it. Replace the foam brush every 10 minutes as it swells and loses its stiffness. Someone will come along with techniques that will make it even easier to apply.

In conclusion, there is only one Sikems job I've seen that was acceptable and that was on a Sea-Ray with a thin toe rail and a little teak on the anchor/bowsprit. He used mostly the clear coat. Most other jobs I've seen, could have just as well been done with a cheap brown paint.

It's only been 8 months but the heavy traffic areas have stood up well. (It's supposed to have 10 times the wear resistance and 100 times the UV resistance of ordinary varnish). I've had to build up a sharp corner and some small fish-eyes but, so far, so good. It's well worth the extra cost, both in time saved in application and in longevity. The true affirmation is the many, rave compliments the boat gets. Looking forward to lots of varnish-free sailing.

The only negative comment that I've heard about Bristol Finish is that if you use it on an edge, you'll start to get water underneath the Bristol Finish and it will start to separate the teak from the varnish. When this happens to my regular varnish (I use Epifanes), I take the damaged area down to bare teak and lay on new coats.

The problem with Bristol Finish is that it's EXTREMELY tough to take off. You can't use a heat gun with it, because the amount of heat you'd have to apply would damage the wood underneath. You can't just scrape it off, either ... because it's super-tough. At least, that's what I've heard. Basically, once you put the stuff on ... there's no easy way to get it off. This can be a major problem if you damage the finish (with water intrusion as described above, or gouge it with an anchor, or whatever).

I talked with the president of Bristol Finish at the Miami Boat Show last month (he had a booth). I listened to his pitch. He claims to live on a wooden sailboat in Ft. Lauderdale and has been using his product for 10 years on his boat. He claims that it needs a simple sanding and two coats every year. I told him about the objection that I'd heard about how difficult it is to remove, to which he responded that if you maintain it right, you'll never have to remove it! This might be true, but damage WILL occur to brightwork no matter how it's maintained ... things will happen that are beyond your control. Therefore, you need a solution (in my opinion) that can be easily removed and re-applied when necessary.

We've not used Bristol Finish on our boat, but did help a fellow out last year who used it on his boat.

Bristol looks very good, with a rich, deep, fast-building gloss - that's the good news.

The bad news is that it was an utter PITA to apply on a vertical surface, because it's own weight would tend to make it sag and drag.

On flat surfaces, BF's fast cure and tendency to rapidly form a surface film really did work well and gave a good finish with minimal sanding. But on verticals the uncured product would slough away under the surface film - it was very frustrating to finish a bulkhead, and then watch the BF start running and crazing 15 minutes later.

The vertical bulkheads required us to thin to nearly 5:1 and apply many coats to small areas. This process was as much - if not more - work than a more traditional varnish, and I'm not in love with the end result which was neither as deep or as glossy as the other surfaces.

I'd use it for small vertical or horizontal/sloping surfaces but would hesitate to do an entire doghouse in it.

We're currently using a two-part Canadian varnish 'system' called Tuf Shield, which is working very well and is proving to be as tough and tenacious as the manufacturer claims. We're quite satisfied with the results, although it would have been somewhat cheaper to have simply saturated Nonchalant in good single-malt Scotch ...

I tried Tuf-Shield ... what a disaster ... be sure it is what you want cause you'll never get all of it off.

Close to true, Tuf-shield is remarkably tenacious - the only thing worse to remove is a European product called Coelam which will seal almost any deck, but is a total PITA to remove. There is one product which will remove both Tuf-Shield and Coelam without a major heat/scrape/sand session: starten

I subscribe to Professional Boatbuilder. They say that the real problem is that the increased heat will push the catalysis of the polyester a bit farther along. This resin shrinks a bit and that's why you get print-through of the fabric. This continued cure occurs even on decades-old boats. Except aesthetic, it's no inherently serious issue.

We've read about shrinkage of fillers; lots of the lighter weight fillers carry that admonition against overpainting with dark colors.

I awlgripped my boat last winter and spent a lot of time considering a dark hull. For me, it was a medium dark blue, but not the blue/black flag blue that you see a lot. I talked to a dozen dark hull owners and a half dozen paint shops. One guy clarified the decision for me:

He said there is only one reason to paint your boat blue: It looks good. All the other reasons are against it. The paint costs more, it will show dirt and salt more, it is hotter, shows scuff marks more, is more difficult to repair, and will show it's age sooner.

Sigh. Maybe next time. I painted it white.

... Under the summer sun in Florida, a white hull may only reach 100 F to 110 F. However, under the same conditions, a dark-colored hull can easily reach 180 F. In some fiberglass boats, the higher hull temperature can cause post-curing, in which the resin in your hull cures further, revealing a fiberglass mat pattern that was until then invisible. ...

Through the years latex paints have developed to the point where 100% acrylic latex paints are better than oil paints on all counts. They are more durable and tougher. They resist chalking and fading, retaining their color especially well when exposed to bright sun. They are easier to apply, going on more smoothly and with less brush drag. They have less tendency to grow mildew. They have almost no odor and no fire hazard. Cleanup is with water. They can be recoated in as little as one hour.

The 100% acrylic latex is the key to the outstanding latex primers and paints now available. The weather resistance of these polymers parallels that of the acrylic molding powders that make red automobile taillight and stoplight lenses that last forever without fading. I checked out all the top-quality exterior primers, paints, and porch and deck paints at both Lowe's and Home Depot - they are all 100% acrylic latex products.

[From same section, not sure if any are from Dave Carnell:]

You want to be sure to brush or roll coats of latex paint out well. Resist the temptation to put on a nice thick coat; it may lead to trouble.

... a further note on thickness: A painter told me to roll the latex on first, then brush it in with a good brush.

Exterior latex is designed to use without a primer. ...

From MikeLongshore 9/2011:
From earling2 9/2011:
From ron II 9/2011:
From Soundman67 10/2011:

Traditional oil based (alkyd) enamel paints are a favorite coating of mine. They brush on nicely, are inexpensive and work great for painting the old metal mailbox on a 75 degree, blue sky, summer sort of day. For use in cooler and wetter conditions many people will add a drier to the enamel ...

Getting these 'oils' to dry in a wide range of conditions and over chemically active surfaces can be a challenge for the manufacturer and a disaster for the end user. ...

...

BIG WARNING FLAGS with enamel over a fresh (less than a few months old) epoxy base. Most (not all) epoxies contain a chemical called Nonyl Phenol that will slow the drying of enamel to a crawl (tack for weeks!) under certain conditions. ...

Acrylic latex paints weather very well, don't tolerate mechanical abuse very well, and are tough to sand with the finer grits.

Oil (Alkyd) paints don't weather as well and will chalk sooner, tolerate abuse better, and sand more freely.

Porch and deck alkyd enamels are formulated for a little extra toughness.

Boat enamels (e.g. Brightside) are glossier than ordinary alkyd paints, don't cover as well, and are more costly.

Peel versus Bead Blasting:
I had my '85 Pearson 303 bead blasted last spring [2000]. It had all the original bottom coats and looked like a "Moonscape". Two professionals did a good job right down to the bare gel coat - looked like there was NO original barrier coat - just paint. They didn't overdo the blasting and left remnants of paint without damaging the glass. However, the blasting exposed a few hundred small voids (air bubbles) from the orig glass lay up of the hull. These were NOT blisters, no trapped oil or gunk in the 1/32 - 1/16 inch sized holes. I had to squeegee/fill the voids with Interlux watertite epoxy (good stuff for sanding - not hard like Marine-Tex), then sand, fill, etc several times. Then barrier coats + bottom paint, etc. Final verdict - The blasting cost me $650+ and a lot of additional work that I don't think I would have to do if I peeled it!!! If I ever have to do it again, I would take the slower peel route and probably do a better job in the end. The yards like the blasting 'cause it's faster - not better.

I used Peel Away on my Hunter 35.5 and it was great. It took several years of hard finished bottom paint right down to the fiberglass. I bought a five gallon bucket of the stuff from West Marine for about $300. But we had to buy more paper to cover -- they didn't provide enough paper for the 35.5 hull size. However, we worked in cool northwest spring weather and left it on overnight. Scraped off easily the next morning. I agree with Practical Sailor -- it appears to be the best on the market at this time.

Good luck on an unpleasant task.

I stripped 24 years worth of bottom paint with PeelAway last spring.

I tried both PeelAway marine strip products: PeelAway Marine Safety Strip and PeelAway Maine Strip II. One was about $100 per five gallons and the other was $230 per five gallons.

Each worked well; I almost think the less expensive one was better.

You will need more paper than comes with the five gallon drum, so be sure to pick that up ahead of time.

I went through a five gallon container of each product (10 gallons total) and could have used another gallon.

The product is very temperature sensitive - the warmer the better. I used it when nights dipped into the high 40's/low 50's and did not get the full effect of the chemicals. If you can wait for the warmer days/nights you will have better results.

My technique was to apply it on a Friday evening then scrape on Saturday.

One big mistake I made when using it was when I started to scrape the paint off I tackled a large section - the paint was loose and it left a watery residue. By the time I went back to wash down where I first started scraping, the paint residue dried almost harder than before I started. This meant more PeelAway! So I got smarter and worked on smaller sections and washed off the paint residue before moving on to the next section.

It is a very labor-intensive and time-consuming job. If I were to do it all over again I would consider having the bottom sandblasted or professionally peeled.

I figure with the peelaway materials, drop clothes, applicator brushes, etc it cost me $500 plus three weekends to get a 26 foot Pearson with 24 years of bottom paint down to bare gel-coat. It was my first boat project - so I probably was a bit slower / less efficient than most people.

Other tips:

• The more airtight and fewer air bubbles between paper and chemical the better.
  
  
• Paper comes in 3 feet by 6 feet sheets. I cut them in half.
  
  
• The more expensive product has a thicker consistency. I applied it with a six inch paint scraper.
  
  
• The less expensive product I applied with a wide paint brush (cheap throw away kind).
  
  
• The thicker the coat the better it worked, but the more product needed. Need to balance this with time and money constraints.
  
  
• I would plan on two applications, unless you do not have many layers of paint.
  
  
• A painters jump suit is a must - buy a couple for $10 each and throw away when done.
  
  
• The more expensive product will burn your skin if not washed off. I learned this first hand - a dime size glob landed on my neck and I did not realize it for an hour. Washed it off and was left with a nice red mark for a week.
  
  

Other tools required:

• Utility knife/razor blade to cut the paper and pop airholes.
  
  
• Buckets of water on hand to wash skin and tools.
  
  
• Roll of tape to help the paper stay on the boat in windy conditions.
  
  
• Drop cloths.
  
  

All in all, the bottom came out great!

I haven't used commercial stripper, I made my own and it worked well -- recipe follows.

First a warning -- Gloves and goggles are a must. This stuff is nasty and will burn you or your clothing. Also air temp must be 50 degrees plus (warmer is better).

You need:
1 can lye (supermarket)
1 box cornstarch (supermarket)
3 plastic buckets
Misc. scrapers, rags, and clean up equipment

To start -- add 1 can of lye to 1/2 bucket COLD water (basic Chemistry rule -- add the chemical to the water).

Add the cornstarch to the other bucket 1/2 full of water; stir well.

Slowly add the cornstarch mix to the lye mix with stirring until the mix is about the thickness of pancake mix.

Glob the mix on your bottom paint as thick as possible.

Go get a cup of coffee, can of beer, nap.

Come back in 1/2 hr and start scraping the loosened paint; dump the scrapings in bucket #3 for proper disposal (bottom paint contains nasty stuff).

It might be necessary to go around more than once. Finish with a green pad cleaning thing, rags, and warm water. Flush the whole thing with water when done several times.

I tried this formula. It works well on bottom paint, not at all on epoxy. It is slow acting so you have plenty of time to decide when it is "cooked" enough. I ended up using Dolphinite, which I think used to be known as Nutek. This stuff really works! Near as we couild figure it lifted/loosened about 5 coats in one application. It is very expensive $280 / 5 gallons. I ended up using about 25 gallons for a 37' tri. A word of warning - it doesn't appear to care whether it is paint or fiberglass so you do have to watch your times. 30 minutes was a minimum for me and in some areas close to an hour. Application thickness of about 1/8" worked the best, anything less resulted in a second application.

Be careful who you hire to do grit blasting. I've see 'professional' grit blasters, who contracted with boatyard customers, blast all the way through the gel coat, leaving a very porous surface to repair. I've also seen boatyards quickly paint over those porous surfaces, with bottom paint, before the customers had an opportunity to see what the blaster had done. I'm sure that such operators are a minority, but it is probably a good idea to be aware.

• Ways of stripping bottom paint:
  • Scraping.
  • Wet sanding.
  • Dry sanding.
  • Sand blasting.
  • Soda blasting.
  • Chemical strippers.
  • [Not mentioned:] Peeling.
  
  
  
• Even a chemical stripper touted as "green", environment-friendly, biodegradable, etc produces hazmat sludge and runoff once it is mixed with the paint it is stripping off. The waste must be protected-against and disposed of properly.
  
  
• In the test, Franmar Soy Strip got "best choice".
• Apply stripper starting at keel and working out toward waterline, to keep it from dripping on you. Do scraping in same order.
  
  
• Read directions carefully and follow them; products have varying characteristics, and leaving them on too long can let the sludge re-harden, or can damage the gelcoat.

Soda Blasting:

Like sand blasting, but using baking soda as the medium. Much less abrasive than the usual stuff. Had it done on the Ranger 23 we previously owned. Took the paint right off and left the gelcoat with a slightly-abraded surface, perfect for the barrier coat.

As someone else commented, it's all in the operator. They can leave paint on or dig right down through to the glass. Be there and watch (and wear ear plugs).

Re: sandblasting

Dry / wet blasting remains the only effective choice for perhaps METAL hulls. I assume you have a fiberglass hull, so the following should apply.

Blasting of ANY kind destroys the gelcoat integrity. The difference between dry and wet is simply that wet takes longer for the inevitable to happen. The net effect is to make the gelcoat porous, and a porous hull WILL lead to blisters, even if you want to seal the hull again after the blasting.

Furthermore, the application of the wet blasting media needs to be done at an exact angle. If the operator makes a mistake, they are not likely to tell you and will remedy the result of their errors in another method without advising you - human nature, that's all.