Boatbuilding Blog

October 2, 2007


Filed under: Building - Before Flipping, Building - Cabin, Building - Interior — tomlarkin @ 1:37 pm

We flipped her over yesterday. With the great help of two friends – Jim and Eric, we got the task done in just a few hours. Not even any injuries!

There were some challenges – mostly that the tent it’s in is only three feet wider than the boat and only 18 inches higher than the beam of the boat. And the tent frame is too fragile to fasten anything to for lifting. So what we did was to spin it more-or-less in place, using ropes and come-alongs.


Here’s a sequence showing the whole process.

(Link to full-size images, hosted on Microsoft SkyDrive.)

Saturday morning I raised the stern with a hydraulic jack, set it on sawhorses, and dismantled the strongback. The bow is resting on the stem piece.


Then I swept and vacuumed below.  I built a sled from a sheet of plywood with steel eyes to hook 2 come-alongs to.


Then I slowly lowered the stern to the deck. I jacked up one side of the boat so most of the weight was on the sled.  Meanwhile, I ran four lines (2 on each side) from the internal bracing around the boat and through holes punched in the tent walls to solid points on either side. The South side mounted to the house, and the North side went to a canoe rack I’d installed a couple of years ago.  I replaced one of the South lines with a webbing-style come-along because I knew that would be the line that needed most of the lifting force. You can see the lines below.


Early Sunday afternoon the guys showed up and we jacked the North side up bit by bit until all the weight was on the sled. We took up the slack on the South side lines and removed the supports and the boat stayed up like we hoped it would.


More lifting. You can see the temporary diagonal braces bolted to the bulkheads. At this point we couldn’t raise any more because the side of the boat hit the tent poles on the South side. So we slid the bottom corner of the boat North using the come-alongs hooked to the sled.


More sliding. We’re approaching the point where she will want to fall to the left instead of the right, so we tightened up the North side lines.


I’m testing the line as the others stand wisely out of the way in  case she slides or falls.


Adjusting the blocks on the sled.  She was pretty stable in this position with all four lines tight. As far as I could tell she didn’t flex at all while we did the turning.


A little further…


Once she was fairly stable on her side we moved her over on the sled by rocking her forward and aft until she was in the right spot.


Jim and Eric lowered her down by letting out the lines a little, one at a time. Each line went through a pulley to a cleat, so they had pretty good control all the time. 


Moving the sled over to keep her centered in the tent.


Almost down! You can see Jim on the right letting the line out while Eric and I steady.


She’s upright! I’ve never had such a complicated series of tasks work so well, with few unforeseen problems. A lot of that is due to the thought and safety-consciousness of the guys helping.


After flipping, we had a great meal made by Meryll, drank lots of beer, and sat around for a while. Jim had to leave, so Eric and I spent a while leveling her with jack stands and various blocks.  Then we drank some more beer!

Bottom Paint

Filed under: Building - Before Flipping, Building - Painting — tomlarkin @ 12:47 pm

I rolled on 2 1/2 coats of red Interlux Micron CSC bottom paint using the ‘Rollerfoam’ rollers. It went on well, although pretty thick. The last half coat was as recommended on the can – adding extra protection to the high-wear areas at the stem and keel. I saved about a cup from the gallon for touchups when I launch.

I made the waterline about 1 1/4 inches above DWL. I hope it looks OK when the boat is in the water.

Bottom  Stem

September 16, 2007

Notes About Epoxying, Priming, and Painting

Filed under: Building - Before Flipping, Building - Painting — tomlarkin @ 11:04 am

(From spending way too much time searching on the internets 🙂 Your mileage may vary.)


  • You don’t need to prime epoxy, but it helps make a really smooth surface.
  • You really, really need to wash the surface – even if your epoxy says it’s no-blush.
  • Adding pigment to the epoxy makes it easier to see how fair the surface is.
  • Alternating epoxy pigments and primer colors makes it easier to see if you’ve sanded through a layer.
  • Wash each layer well, and give the epoxy lots of curing time before topcoating.
  • Learn how to roll & tip paint for a great-looking finish.
  • EasyPoxy, Awlgrip, and Interlux are the most popular paint brands, and all seem to work well.


Barrier Coating, Finishing and Tips

Apply a minimum of two coats of WEST SYSTEM epoxy for an effective moisture barrier. Apply three coats if sanding is to be done. Moisture protection will increase with additional coats, up to six coats or about a 20-mil thickness. Complete all fairing and cloth application before beginning the final coating.

Wash the surface with a Scotch-Brite pad and water to remove amine blush. Dry with paper towels.

Let the epoxy cure very, very well, wash the surfaces with a 10% solution of ammonia and water, then get it very clean with plain warm water…then sand it…and if the epoxy is completely should have no paint adherence problems without a primer. Without a good cleaning with water/scotchbright scrubbing or ammonia/water then water scrubbing…you just sand in any blush that might be around on the surface.

If a high-build or filling primer is to be applied, 80-100 grit is usually sufficient.

After you are satisfied with the texture and fairness of the surface, rinse the surface with fresh water. Rinse water should sheet evenly without beading or fisheyeing. If rinse water beads up (a sign of contamination), wipe the area with solvent and dry with a paper towel, then wet sand again until beading is eliminated.

Then shell coat the part with pure epoxy and allowed to dry for 3 days. Don’t skip the 3 day part or you will be sorry.

The pigment makes getting a good finish on the epoxy much easier. Tiny bubbles and slight irregularities show far better when there’s some color in the epoxy. And white will show this best.

Too much epoxy is not really any better than not enough. With 6oz cloth I have usually found that the second or sometimes third coat rolled on is enough.

For the first two coats I used FLAG Resin and slow hardener, then after getting a little smarter, I switched to MAS Low Viscosity Resin and slow hardener for its better self leveling characteristics (all things being relative, the latter was a breeze compared to the FLAG resin applications –don’t do that for barrier coating unless you have a lot of patience and flat surfaces only). After each barrier coat application I sanded by hand, my best sander, with 3M 220 Imperial (stikit – the newer purple stuff).


Process for Applying High Build Primer –

There is nothing in most primers that sticks any better to properly sanded epoxy resin than there is in the paint itself.

There is a difference between sanding raw laminating epoxy, which doesn’t cut well at all, and sanding primer, particularly a high-build primer which cuts like silk. Drudgery is in the gland of the laborer.

Primer doesn’t add anything unless your filling/sanding job isn’t very good and you have a lot of small irregularities to hide. The paint goes on and sticks just as well to properly sanded epoxy as it will to primed epoxy. If you did properly fill and sand the surface, it should be just as smooth in the epoxy state as it would be with multiple coats of sanded primer. You can prime if you really enjoy more sanding and like to watch your sandpaper fill up, but is isn’t going to do anything to improve the paint jobs texture or adhesion.

WEST 105/205/barrier coat additive, topcoated with plain 105/205 then sanded to 120 on a random orbit with no primer and Brightside rolled and tipped over it. Work done outside in the summer, no thinner added. I have had good luck with Brightside in years past. I used a foam roller and a very good badger hair brush on fancy jobs. Need to move fast and keep the wet edge. Experiment with thinner to help it flow and keep wet edge. I rolled vertical and brushed horizontal and except for one spot where I lost the wet edge, people thought it was a spray job.

Sandable primers, as what was told to me were only to be used for minor surface imperfections and microfairing and were thus sanded semi transparent as to not shrink and move at different rates than their compatible top coats and was in no way to make up for fairing work of the substrate.


Pettit’s Easypoxy Primer covered the epoxy very nicely, and sanded out easily.

I used to use Interlux, but I now use Petit EasyPoxy. The EasyPoxy is really tough.


Two coats of Awlgrip 545, which stinks like hell and probably gave me cancer, but is the best paint I’ve ever worked with. mixes easily, rolls on evenly with great coverage and sands like a dream, especially when compared to sanding epoxy.

The industry standard these days is Awlgrip 545 primer. This stuff is works really well, but it ain’t cheap. I used some System 3 epoxy primer on a multihull last year, and I was not happy with the application or the result. The advantage of that epoxy primer is that it has low VOC’s, which is great….but the performance was really lacking, so back to the respirator and the 545…or this new stuff.

Interlux 404/414

I have been using Interlux Epoxy Prime Kote 404/414. It is a multi-purpose two-part epoxy primer for use above and below the waterline and it makes a great sanding surfacer. Sprays and brushes very well. Alternate color of primer surfacer to help pick up low spots/scratches. Epoxy primer can be easily tinted with resin colorant.

I’ve been using the Interlux 401/404 epoxy primer with good results. It’s a bright white color with a flat-ish finish, so you can use it as a finish coat for some interior applications–lockers, bilge, etc. It’s a lot less expensive than the Awlgrip product. The 404/414 is a good surfacing primer. It sands well. It’s a bit porous, so it takes stains easily.

I’ve applied gallons of the stuff with the small foam rollers from home Depot: “rollerfoam “” ultra fine foam for the smoothest finish ” “all paints and coatings “. I’ve always added the maximum thinner recommended; 25% of the 2333N Brushing reducer .This has lain out smoothly for me ,though I carry a foam brush to tip if needed. Answer – Used the “Rollerfoam” that Bill Perkins recommended–worked like a charm. Used one roller cover for the whole bottom and topsides of this 18′ ft. boat. Coat tended to stipple, especially as the 404/414 began to cure–so used a foam brush to tip it off.

Answer – don’t roll and tip the primer! Just roll it on with a tight foam roller cover, let it cure, then sand it smooth before topcoat. Sand it down to 220 or 360 grit


Roll & tip instructions:

I think the key is not loading too much paint on the roller pad… apply an even thin coat of paint but not any more than necessary on the roller. This fairly thin layer of paint… when tipped just layes down very smooth and uniform. I found that the badger brush works better because I think the tips of the brush seem to stay more wet than the foam. Brightsides is good too. I prefer Easypoxy and am used to it.

Epoxy Bond Failure

Filed under: Building - Before Flipping — tomlarkin @ 10:33 am

When I put the 6 oz glass layer on the boat I followed the standard advice to fill the weave of the cloth the same day. The rule is to add a few more coats of resin on the same day, adding each coat when the previous one was tacky. This is supposed to create a great bond between the layers, without the need to sand or to wash off any amine blush. I did exactly that, rolling on two layers the same day I added the glass. The final coat was complete at about 9 PM that night – a long, difficult day. The boat looked great! The weave was filled. I had dreams of turning the boat over in Mid-July.

A few day later I washed the hull and sanded the whole thing with a longboard and a random-orbital sander. While I did that I noticed a few areas with a strange feathered-looking edge where I had sanded the top layer pretty thin. One day I took a putty knife to one of the areas. To my horror, the putty knife slid under the layer and peeled off a long strip of epoxy!

Putty knife scraping off epoxy and fairing compound

I was shocked, but hoped it was just in the one place. It wasn’t. Everywhere I tried, I could do the same. Some places adhered better than others, but most could be peeled off the same way. Some areas had two distinct layers. It took a lot of time to do even one square foot, and I occasionally gouged through the glass layer into the wood. The good news is the glass layer itself seems to be attached well.

This was the largest piece I scraped off I spent weeks scraping the hull, from mid-July to early September. It was incredibly depressing, moving backwards instead of turning the hull upright and starting the interior. By September first I was done, and the hull was stripped down to the glass, sanded, and ready to move forward again. 

I still don’t know what the problem was. When I was adding the fill coats I reused the mixing buckets and the foam roller. Maybe the partially-catalyzed resin contaminated the mix. Maybe I didn’t mix the epoxy enough (although the layers cured fine). Maybe the humidity changed and dampened the hull between coats. I have no idea. I don’t think it was a bad batch of epoxy. I tried some tests with the same 4-gallon container and didn’t see the same problem.

June 20, 2007

Hull is Glassed

Filed under: Building - Before Flipping — tomlarkin @ 2:36 pm

After a week of preparation I completed the glassing in a single long day of work. I finished the last filler coat just after midnight Sunday night. I’m very pleased with the results. Aside from a few bubbles and runs the surface is smooth and fair. I did the bottom in two long strips and the sides in a single long piece wrapped around from the bow.

Starting the side glassing at the stern. You can see the epoxy from the bottom sheathing bleeding through the new layer. The bottom epoxy got very tacky half way through and made if very difficult to pull out the wrinkles as I applied the sides. Before I discovered the painting hood I had to cut out chunks of hair after every glassing episode. The coveralls are from an auto body shop. The front is waterproof ripstop nylon and the back is thin cotton. They last a lot longer than the Tyvek ones from the hardware store. The gloves are from the same store and are extra heavy and long to keep epoxy off my wrists.

Glassing - small

After the glass but before the first fill coat. The flat effect is from squeegying out the excess epoxy to bind the cloth tightly to the hull.


The additional coats of epoxy filled the glass weave well and left the finish pretty glossy.  Now I need to wash it down to remove the amine blush and start sanding and fairing. 


June 16, 2007

Miscellaneous Progress

Filed under: Building - Before Flipping — tomlarkin @ 1:41 pm

To prep for glassing the hull I had to sand a flat spot along the centerline of the bottom for the keel to lay onto:

Sanding the flat for the keel.

I laid on a couple layers of biaxial tape to strengthen the joint. I did the same for the bow, sanding a 2 inch wide flat to add the external stem and glassing it the same way.

Glassing the bottom centerline.

I added the final layer of the inside sheer and the inside longitudinals at the rubrail height that the decks will mount on.

Sheer laminations

Now I’m sanding and filling to prepare the hull for glassing. I realized that the way I was going to install the glass cloth would leave about 7 feet on either side with only one layer of cloth at the side-bottom joint so tonight I added a single layer of biax tape the joint all around. Again, more fairing, but a stronger boat. At the joint where the stern meets the hull side I did as the book suggests and made a 3/32 inch deep notch 6 inches wide and laid in 2 layers of biax. The power plane let me make both notches in less than an hour. The top of the cloth came out flush with the hull surface and I faired it in easily.

Next steps:

  • glass the hull – this weekend
  • add the center keel strips
  • add the stem – inside the hull and outside
  • add the twin skegs
  • add the rub rails
  • fair the hull
  • prime and more sanding
  • bottom paint (probably copper flakes mixed with epoxy)
  • flip! Now I’m hoping for this by the end of July or early August.

Butt Lift

Filed under: Building - Before Flipping — tomlarkin @ 1:15 pm

I made a serious mistake when I assembled the boat. The aft part of the bottom panels lay against each other in a way that made them lift in the center instead of coming together flat across the stern. The pictures will make that statement more clear. All the parts fit so well that I assumed the hull had to look like that so I glued it all together that way. I wasn’t until I laminated the stern on and sanded everything that I realized that the shape was really wrong. Instead of a smooth horizontal sweep about 4 inches above waterline the stern dropped down to the waterline in a gentle vee shape.

I spent a couple of weeks trying to rationalize that it was OK – that maybe one in a thousand would notice or care, but I couldn’t convince myself. I knew I’d see it every time I looked at the stern and it would always bother me.

So I fixed it. Actually it was pretty easy. I just cut out a wedge on either side and pulled the bottom plywood down to the new location. Since these cuts weakened the stern joint I added two layers of biaxial tape to the joint. It’s going to cost me some time to fair it all, but I’m really happy with the results. Now it looks just like the plans.


Before the butt-lift

During – the removed wedge was about 3 inches high at the inside corner:

During the operation - wedges cut out of the stern and motor well sides.


After butt lift - ready for glassing.

Motor Well Planning

Filed under: Building - Before Flipping — tomlarkin @ 12:45 pm

The plans call for an inboard diesel but I’m going to use an outboard instead.  Diesel fumes – both exhaust and raw fuel – make Meryll sick. Also, removing the motor from the center of the boat adds interior space and isolates the noise and fumes away from the living quarters. Not to mention that installing a motor looks like hard work! Another factor is the prop shaft through the keel adds at least an additional foot of draft that I can avoid with an outboard. I want to take this boat in very shallow water and beach it on sandbars once in a while.  See the ‘Twin Keels’ entry for more detail.

The decision to make the motor completely inside the motor well was easy – I didn’t want to make a huge hole in the stern! I think the round stern is one of the most beautiful parts of the boat. Therefore I had to mount the motor forward enough to be able to kick up inside the cutout. The cutout dimensions I ended up with were 18 x 40 inches. I have some half-baked ideas on how to mount a kicker in-line with the motor but I won’t be able to see if they will work until the boat is right-side up.

To start the planning I mocked up a motor well on the back of my runabout in the driveway. The runabout has a 45 hp Honda four-stroke. I’m planning on using a similar (or maybe even the same) motor on the Godzilla. 

Motor well cutout planning.

Once I had minimum dimensions, I laid out various plans on the bottom of the boat in blue tape. I had to make the cutout and install the sides of the well before I glass the hull, so I couldn’t put this step off.

Stern layout marked with painters tape.

Once I had the plan I wanted I cut a huge hole in the bottom of the boat.

   Hole in the bottom. 

Then I realized the prop wash would splash inside the well so I made the hole even bigger!  I glued in the sides of the motor well and called it a day. The cross-bar is just to brace the plywood while gluing. The small hole on the centerline of the bulkhead is on the waterline. The draft at that point is about six inches.

Big hole in the bottom.

May 10, 2007

Progress: Two Tasks Completed (almost)

Filed under: Building - Before Flipping — tomlarkin @ 2:02 pm

I’ve got the bottom sheathing on. It’s a layer of 1/4 inch ply over the 1/2 inch bottom panels. This layer really stiffened the bottom. I can walk on it without a bit of flex.  I was really concerned about having voids under the layer so I predrilled lots of 3/16 holes. I covered the holes with tape so the epoxy wouldn’t run out, but any trapped air would have an escape path. After wetting out both sides I pressed the panel down and then drove washer-head screws through many of them. Then I put a lot of weight on top in the form of big bags of mulch and some large rocks.

Now I’m laminating 1 x 2 boards as the sheer clamp. I think I’ll add four layers for a total thickness of 3 1/2 inches. I may add a teak sheer caprail if I have the cash when I get there.

I’m starting a mockup of the stern, built to scale on the back of my runabout. The runabout has a 45 horsepower Honda outboard and a 10 horsepower kicker, about the sizes of motors I plan on putting on the boat. I need to decide how wide to make the hull cutout and how to mount the kicker.  I have an idea of mounting the kicker inline with the motor, toward the stern. I need to see if it will fit. I’ve never seen a layout even remotely like it.  I’m trying to minimize the amount of hull (and flotation) I need to remove when I make the cutout. I don’t think it’s safe to go on the water without a backup means of propulsion.

I’m also in the process of sanding the bow and the bottom seam flat, and rounding the hull/side edge to glass the hull. Then I’ll add the stem and keel deadwood and rub strips. After putting on the rubrail (and priming?) it will be ready to turn over. I don’t expect to make my self-imposed deadline of July 4th to turn over, but it should happen sometime in July.

April 4, 2007

Wrapping Up the Stern

Filed under: Building - Before Flipping — tomlarkin @ 11:42 am

Here’s a set of pictures of the stern being sheathed. The round stern is made of two layers of 1/4 inch plywood laminated together. Quarter inch ply is surprisingly uncooperative when bent to such a tight radius. It took a lot of encouragement and a little coersion to make it conform.

The first sheet:

First sheet

Inside of the first sheet:

Trimming to fit. I pre-trimmed the rest of the sheets which made them easier to bend and install.

Outer layer. The drips are from holes drilled so you can see if there’s enough epoxy between the layers. I didn’t thicken the laminating epoxy enough and it started dripping out from between the layers along the bottom. Plastic tape and lots of clamps held the glue in place long enough for it to cure. The vertical 2×4 left of center is the clamp bending the ply to the boat while the screws are driven. It’s braced at the bottom and pulled tight with a line running to a cleat screwed onto the bow.  This outer layer lays into a 4 inch wide dado in the 1/2 inch hull plywood. This makes the joint more fair and spreads out the forces. The notch was easy work with a power plane. What a great tool!

I added this layer on the stern last Saturday. I hope to laminate on the last piece on Thursday. We’re having a ‘morale event’ at work on Thursday – the whole team is going bowling. Laminating plywood is a much better way to raise my morale! 

Next: Clean up the stern, laminate the 1/4 inch bottom sheathing, sheer clamps.  Then glassing the hull, adding the bow pieces and the keel(s) and rub strips. Sand, fair, bottom paint, flip it! I’m still aiming for the turnover around fourth of July – three months from now. Possibly feasable, but a lot of work to get done by then.

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