Do bottoms really need to be painted?

Discussion in 'Wooden Boat Building and Restoration' started by LP, Jul 9, 2012.

  1. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I have a little runabout I built back in '88 that hasn't a drop of paint anywhere. It's stored indoors and hasn't seen any issues because of is only varnished bottom. You don't need bottom paint, unless it's in for extended periods, which your boat appears to have avoided. As you well know it's all about upkeep. If you stay after it, the maintenance isn't so bad, but let it go and you have to pay for it in time and materials. A bit like my first wife.
     
  2. LP
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    LP Flying Boatman

    Getting to the bottom of it all.

    At last, my situation that prompted this whole pictorial essay. A boat on a trailer that needs new paint on the bottom side. So rhetorically, do bottoms really need paint. Fortunately, my bunks are removable and a little WD40 and a bit of elbow grease and an hour later, the bunks are out of the way. We'll talk about what is holding up half of the boat later. Then there is all of the sanding. Then there is laying to waterline that has not been done on this boat. And then, there is the painting. Boating is fun, right!? :rolleyes:

    I has tired of the multicolored bottom, so necessity is a mother of something, I think. The original paint on the bottom only covered the very bottom of the boat where I had used SWP and it contrasted too much with the cedar strips of the bilge and sides. I was going to pick another plank line to follow with the new color, but it would have carried to high on the bow and given an more amateurish(sic?) appearance. In the end, I was going to have to bite the learning curve bullet and put on a real waterline. All of my builds have always had psuedo-waterlines that are referenced to some feature on the boat, be it a plank line, chine or whatever. This was my personal cheat to avoid the waterline issue and it helped to hide construction details or emphasize others.

    I chose to go with the tube filled with water technique. Simple enough, right? It was an interesting journey to say the least. I used a 20' long 3/8" diameter clear tubing. I went with a larger diameter as I felt it would offer lower resistance to water flowing inside the tube. One end was taped to the transom and the other was held nexr to it. the free end was adjusted until the water in each end was level to each other. This level was marked and became the reference for level. I think this would be a simple procedure if the boat sides were plum, or nearly so. Portions of my hull are nearer to horizontal than they are to vertical and this makes for some difficuties in choosing the level point on the hull. Laying the tube over to lay against the hull make you level line unusable and holding the tube vertical requires and estimation of the actual level point on the hull. Of, and don't drop your tube as this causes a loss of water and you have to recalibrate your water level again.

    I put a waterline mark on my hull every foot to foot and a half. I put these tape markers on the lower side of the waterline so that when all was adjusted, I could mask on the top side of the line and pull the marker afterwards. I would place the markers but viewing the tube from the side with a best guess of level. Once these were on, I went back and view the markers verses the tube from a fore-n-aft vantage and adjusted the markers accordingly. I felt this to be a more accurate estimation of level while the side-to vantage was easier for the initial marker placement. In the process of all of this, I was continually going up and down (fore-n-aft) the hull rechecking the other markers on the hull and checking the calibration of the level. When I could go along the entire hull without needing to adjust any of the marker, I felt I could make the choice to call it good.

    With all of the markers in place, I was ready to start the actual masking of the waterline. I went with 2" masking tape thinking it would bee less likely to give me a squiggy line. I think now that on a hard-chined, developed hull, this would be the case. On my round-bilged hull, I think the wider tape resisted the curvature ofthe hull too much. I made it work, but on the other side I will try 1" tape instead. I might even venture to suggest starting the masking task one side of midships or the other and working past midships to the opposite end of your boat. I think the the masking is easiest to set in place at midships and then it serves as your anchor for setting your masking at the ends. It also give you two ends to work from in setting one half of your waterline. The second half is setting the same way except that you only need to match and fair into the first portion of your masking on one end.

    There was some damage on centerline forward of the keel caused primarily during launch and/or retrieval. I added two layers of glass tape in this area and filled and faired it all. I also had some abrasion on the leading edge of the keel where it did some talking the an oyster bed on the Texas coast. This was also filled and faired and preped for paint.

    So finally, do bottoms really need to be painted? I think so. Even if it is a pain in the backside. :p

    IMG_1513.jpg IMG_1514.jpg IMG_1525.jpg IMG_1524.jpg
     
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  3. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I've long ago given up on water levels. They suck and aren't as accurate as you might like. A moderately priced, self leveling laser is the way to go. You can get one for about 30 bucks and you'll never go back to a water level again. The nice thing is you can "shoot" both sides of a boat at the same time, depending on where you place it. I use three locations typically for a waterline, dead on the bow and at the 3/4's position just aft of each side of the stern. The stern positions lets me hit one whole side and across the transom, so I can check both athwart and fore and aft level during setup. The bow shot will send a line down both sides of the hull, until the hull bends away some place aft of midship. The sweet thing is the line is on the hull, no guessing or using another level to take the mark on a water level under a curved hull, just shoot, mark it and go.

    Tape is a different story, I use the green "fine line" from 3M and the regular blue painter's tape too. On round bilge hulls you need a flexible tape, but one that can be held relatively straight too, so 1/4" to 3/4" fine line is used. Being a vinyl tape it holds an edge like no other (I see some bleed through on yours Greg :)) and far better to shape and bend, than crape painter's tape.

    Once I have a WL shot and marked, it's just a reference line. My usual sequence is to place a painter's tape above this line, with the bottom edge touching. This too is a reference, for the actual boot or WL top. Depending on the boat, I'll pick a thickness, 1.5" to 3" again depending on the boat and how it loads down. Finally I can lay on the boot or WL tape. I start in the middle of the boat and work towards each end. On boats like that one, I'd have a significant sweep or sheer at both ends. I eyeball this approaching the ends, on you boat probably 1/2 as much sweep at the stern than the bow. Powerboats about 1/4 as much, double enders maybe 3/4's as much. If it's a bottom paint line, then the sweep is fairly dramatic, but if it's the bottom of a boot stripe only about half as much sweep as will be used on the top of the boot stripe. This sweeping of the bottom paint line or boot stripe really makes a huge difference when on the water with different trim loads, especially in small craft or light displacement boats. Before pulling the reference tape, which is on the actual WL, I'll scribe a line in the primer with a scratch awl. This will remain visible under the topcoat, for future reference.

    After the green line tape is applied, it's eyeballed to check for fair, adjusted if necessary. Then a painter's tape is applied over it to hold masking paper. I suppose any tape would work for the masking paper.

    As usual, you look to have done a fine job of it and thanks for posting the photos for us.
     
  4. LP
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    LP Flying Boatman

    Thanks for your remarks, Paul. Many things to think about.

    Does your level shoot a line, as opposed to a point? I just acquired a laser level from a neighbors garage sale. It only shoots a point, but can be mounted and rotated. I was planning on upgrading on the other side of the boat and try the laser there. Once the boat floats with the new bottom paint, I may evaluate the need or ability to add a bootstripe based on available bottom paint. With adequate bottom paint, I could work in the sweep to both sides of the stripe. Time and energy will tell on this one.
     
  5. LP
    Joined: Jul 2005
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    LP Flying Boatman

    Floating your boat withoout water.

    The trick to painting your bottom is removing all of the bottom supports without having your boat fall on your toes. The best I could do was to float one side at a time and have most of the boats weight picked up by the other. A small amount was carried by a couple of support struts rigged to freed side.

    The first strut was easiest to rig. A carraige bolt through the strut and chain plate and a little bit of line to hold the base of the strut to the boat and your good.

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    The second strut took a little thought, but the solution was sound and mildly elegant. The adequately sized piece of wood that I found on hand was a superior piece of Southern Yellow Pine with a grain count of about 20 growth rings per inch and straight grain. I didn't want to unjustly cut or drill holes in such a fine specimen of wood. All I had to do was to radius some grooves in one end to let a support line cradle there and the rest of the piece was left unmolested.

    To attach the support, I threaded the line through the aft docking cleat and knotted it to secure the end to the boat. The line was led up over the support strut and back down to cleat level. A bight (sic?) was taken that wrapped around the strut and cleat and was tensioned to provide lift the the stern quarter of the boat. Once tensioned, the loose end was wrapped around the strut and finally tied off with a series of half-hitches. The half-hitches were undone for photo clarity.

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    The painting went smoother and quicker than expected. My bigest concern was with keeping the wetted edge going while dealing with the remaining obstructions; trailer portions and axles and tires, etc. I was also going to have to stop midway and reposition myself as the axle clearance was too little to work under. The paint rolled on smoothly and tipped out nicely. My first section showed signs of wanting to sag so I immediately hit it with an unloaded paint roller. It was at this point that I started using the size of the paint bubbles left by the roller as a guide tothe thickness of the applied paint. Big bubbles: bad. Little bubble: good. I also found that tipping into the wetted edge caused a the paint to stack up there, but tipping away from the wetted edge made the overlap lay down. This is opposite to what works for me with varnish. I always pull into the wetted edge with varnish. I suppose it's different with varnish as varnish is all brushwork. My concern with tipping away from the wetted-edge was leaving a brush mark where I dropped the tip in. This proved to be unwarranted and the paint leveled nicely. Now, if only I had worked the primer to a finer finish..:(
     
  6. PAR
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    PAR Yacht Designer/Builder

    You need a line or rotating laser. A point isn't good for much, except pissing people off in a bar.
     
  7. LP
    Joined: Jul 2005
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    LP Flying Boatman

    Well, my wife doesn't let me ...

    .... go to bars any more.....so I guess I have to do something with my pointer.:rolleyes::D

    A pointer was still better than the water level. I put the boat to level useing the cockpit seating again. The seating is level to the waterline. Well no luck. The laser point didn't line up with both the bow and the stern. The waterlevel was pulled back into action. I set it to the freshly painted waterline and leveled the boat to those points. If my waterline is going to be off....It's going to be off..CONSISTENTLY! :cool:

    Backing up a bit, I built a level shelf on my garage wall just below my estimated waterline and used various pieces of plywood to work my laser level up to the desired height. This height was adjusted several times while the boat was being jockied around to get the waterline to "paint" properly.

    OK, so now I get the laser point on target at the bow and stern, but at midships, it's painting half a plank, 3/8" too high. Well, nobody can see both sides of the boat at the same time, right. Not good enough. I must have had a slight bank to the right when I was laying out the left waterline. After another hour of tomfoolery, I had the boat "level" fore-n-aft and a slight left bank to match the right bank from the first round of exertion. After all is said and done, I'm going to call it sweep, be it ever so slight. :idea:

    Despite all of the fiddling with the boat to get it positioned right, the use of the laser point was the difference in day and night over the use of a waterline level. It went quickly and accurately. A mark was placed about every foot. I still used crepe masking tape, but went with a 3/4" +/- width. This too went smoothly and more easily than the 2" width. Starting at midships and working forward, I was able to eyeball and reset the tape line easily, accurately and fairly.

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  8. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    See, us old pups can learn new tricks.
     
  9. bntii
    Joined: Jun 2006
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    bntii Senior Member

    Sure sure- but we don't like it!

    I was watching some riggers work & the guy pulled a messenger line through a large bow pulpit by tying a washer on the end and dragging a magnet along the tube to pull it though..
    Neat trick & would have saved me loads of time with the various fish tapes I used over the years.

    I tell him "neat trick", & he says- oh that's nothing, my friend Mo uses a vac to pull cassette tape through..

    Another neat trick and simple as can be..

    Nice looking boat LP- in truth I eyeball waterlines.
    If they look good to me they pass muster for everyone else.
     
  10. LP
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    LP Flying Boatman

    I'm still working on the old tricks!:mad:.................................:)



    Thx. bntii
     

  11. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I've used the vacuum cleaner and magnet tricks before. I've not had much success with the magnets as a fish, but the vacuum clear with cassette tape or string works very well.
     
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