Hull work and barrier coating

[minaret]

Originally Posted by Idle

Just educate me.
Isn't barrier coating also an epoxy material?
Why do we apply it over a layer of epoxy?

Because its much more moisture resistant.

[hellosailor]

minaret-
Sorry, I assumed alternate colors meant bottom paint, not the barrier coat. You'd put on alternate colored layers of barrier coat??

[laika]

The job is done! Truly almost went a bit bananas towards the end living on this thing in the boatyard, but looking back it somehow all seems totally worth it.

For the sake of posterity and to help anyone else dumb enough to do this to their boat here's the full breakdown...

The peel in progress..


After the peel, a small crack was discovered underneath the bilge. Once the gelcoat was peeled off, the water in the bilge from a recent engine washdown came gushing out. A bit scary to think that the gelcoat was all that stood in the way of unknown water ingress...


There was also a small crack near the bottom of the stem, presumably from a hard grounding in the past. Another angle of the hull halves..


After peeling, a few hundred small delam zones were ground out. The rudder skeg was the worst area..



Another angle...


A good amount of juice came out over the course of the next few weeks. I washed down twice weekly with a hard bristle brush and Ajax to facilitate the drying process.


Left for winter with boat skirted to protect against UV damage..

[laika]

After drying out in NC from Sept13 thru Mar14, work began to revert the hull back into an actual boat again. First step in my case was to patch up all the delam zones. The deepest of them I added a layer or two of cloth to and then filled with cabosil (west 406)..



The Vancouver27 is a very well built boat, but I was a bit surprised how little attention was given to where the rudder skeg joins to the hull..



I first laid on some 406 to provide a better angle for glassing...


The 406 sanded down and a close-up of the 36 grit soft pad toothing into the hull..


Two overlapping layers of 12.5ounce biaxal cloth laid up to hull/skeg join..




Rudder skeg/strut/shoe glasswork...


Close-up of biaxal layup on skeg...




One layer of 12.5ounce biaxal covered by one layer of 15ounce s-glass (aft-most part of skeg where outboard rudder is fitted)..


Rudder shoe after biaxal layup and 404 high-density fairing compound..


I ran a few layers of biaxal below from the rudder shoe fore of the prop, which substantially stiffened up the strut and skeg..

[laika]

Onto the leading edge...

At first I was apprehensive at the thought of using kevlar, but it ended up not being any more difficult to work with than regular fiberglass cloth. I staggered the lay up in stages to make things easier on myself and less time-sensitive in terms of cure windows (see pic below). I started with strips of 12.5 ounce biaxal approx 5ft long by 24in wide, wrapped lengthwise across the leading edge. I then used approx 24" long pieces of 10ounce kevlar from a roll of 6" kevlar tape and staggered them 3" apart on top of each other (essentially creating a double-layer of kevlar). I then wrapped another layer of 5'X24" biaxal over the top of the kevlar, then another 2.5'X24" layer of biaxal on top of that, followed finally by a thin layer of cabosil squeegeed on top. The kevlar is well buried and the cabosil allowed me to sand after the cure without taking away any of the biaxal, while also leaving the surface free of pinholes or voids.
A more pro job would have been to use peel ply throughout, but I had some difficulty with using peel ply and biaxal..the biaxal liked to snake out and leave voids underneath the peel ply when I squeegeed it out. Perhaps I should have used a finishing layer of regular cloth or s-glass on top of the biaxal to avoid this.

You can see in the below pic the lower section is cloudy from the cabosil top-layer and the upper more clear. I had not yet added the cabosil to the top section..





This is the stem finished and sanded, ready to be prepped for fairing compound..



Filling thru-hulls...

I got rid of 5 thru-hulls and added one, making for a total 3 all within a few feet of each other on the portside: Kingston, raw-water sink intake, and sink drain. I removed 2 head holes (went composting), 1 knotmeter, 1 depth (went in-hull depth sounder), and 1 forward sink drain (two sinks in a 27' boat seems a bit silly).

To plug the old thru-hulls, I made a sheet of biaxal about 1/4in thick from scraps and pressed between some weights while curing. I then cut to size with a hole-saw and sanded them until they fit snugly in their holes. Used the 12:1 bevel rule to grind out the holes and cleaned the hell out of them with interlux 202 solvent. I then mixed a batch of 406-thickened epoxy and epoxied them in place before glassing over them.



I sanded away the paint on the inside of the hull and laid three layers of 12.5ounce cloth down on the inside..


On the outside, I laid up enough biaxal to make up for the beveling, probably about 8 layers ranging from a diameter of 3" to 3'. Overkill! I laid the largest piece down first, then built back out from the smallest.

[laika]

Fairing and longboarding...

I thought I was nearing the end when I finished glassing, but I could not have been more wrong. The fun part was over, and unbeknownst to me a special place in hell still awaited
Longboarding is like Sisyphus doomed to forever roll a giant boulder up a mountain in some deep circle of hell.

After prepping the hull by sanding, washing down and wiping with 2 passes of 202, I did three layers of neat epoxy followed by 2 layers of epoxy thickened with 407 to a mayonnaise consistency. I did this is stages because I was working alone in my free time. Each quarter of each hull side took about 4-6 hours depending on temps and cure times.



Near the leading edge, I used high density 404 as a filler. It was a real PITA to fair out, but it allowed me to shape the leading edge a bit more than I would have felt comfortable with using low-density filler. It has a higher compressive strength against minor impacts...


I must not have laid the 407 on thick enough, because some of the lows were still too low after rough fairing and longboarding. I had to go back over and fill the some of them out a second time..


After the rough fair, sanded with 40grit orbital and just starting to longboard..


Done longboarding. You can see one of the thru-hulls in the center of this pic..




Rudder shoe taped off in prep for barrier coat. I molded out an exact fit for the shoe by laying out some 404, covering with wax paper, and then dry fitting the SS shoe on top..


This is one of the thru-hull areas. I used 404 instead of 407..


Ready for barrier coat prep..


Rudder work...

The rudder had hundreds of very small delam zones which I ground out. I then added 2 layers of 10ounce s-glass..

[laika]

In the end, the entire bottom job probably cost me about $6000-7000US. I was working a job while also working on the boat, so it's hard to guess the exact time involved. Once the boat was dry, I bet I could have done everything in a month's time if I was working full time EVERYDAY on the boat. I used relatively light cloth and kept an eye on added weight..I feel the weight gains were extremely minimal and easily offset by better hydrodynamics (a much fairer hull). Not a performance boat to start with, so all the more reason I feel...

I hired out the peel and the final barrier coating. I used about 9gallons of west epoxy total, 5 for the glasswork and 4 for the fairing. I;m guessing I probably sanded off half of it in the end. I believe the yard used roughly 8-10 gallons of 2000e. They put 12-14 coats on, as is their standard. They did not hot-bond the final coating of 2000e to the bottom paint, as they claim to have had issues with this in the past (?).

Cost Estimate:
$1000 - peel and grinding out the delam zones (hired out)
$1500 - west resin and hardener
$250 - (3) 10yd rolls of 6" kevlar tape
$750 - biaxal and s-glass (roughly 25yards of 5' rolls)
$500 - 3M longboards and tons of sanding pads throughout project
$100 - nitrile gloves
$150 - (3) quarts of interlux 202 and low-lint rags
$2500 - 2000e barrier coating (hired out w/ minimal prep work included)

The project was long and tiresome, but not technically challenging. I had only minimal experience with fiberglass work before this and did not find anything remotely difficult about it (tedious as all hell at times, yes).

If I had any questions along the way, between the expertise in the boatyard and the expertise online through research and the forums (thanks Minaret!), I feel like I did as good or better a job as any seasoned pro would have done. It just took me longer.

I hope all this may be of help to others out there contemplating something similar. I have no regrets and feel I'd do it again if I had to. The boat is a 1982 Vancouver 27 built to a high standard by Pheon Yachts of the UK.

Ryan

[minaret]

Very nice work! Congrats.