How to seal plywood dinghy skeg before repainting?

[OrangeCrush]

Hello,

I need to repaint my new (old) Chesapeake light marine-ply dinghy. The previous owner used Interlux Brightside which I plan on doing as well.

I'm wondering what I should do to seal up the exposed ply before painting. The worst spot is the aft-bottom edge of the skeg (keel?), which is a single sheet of marine ply now thoroughly roughed up and showing its layers. This is the spot where the dinghy gets the most abrasion as it is dragged out of the water on to rocky beaches, etc.

My first thought was to use some west system epoxy with aluminum powder as a barrier coat. I would also consider drilling some shallow holes at odd angles so the epoxy doesn't get chipped off when it drags over a rock.

Another approach would be to sand and paint it as normal, then cover the skeg with some metal sheeting.

What would you do?

[Cotemar]

I would coat and soak the damaged area with epoxy.

Paint with bottom paint.

Add a SS Rub Strake 3/4" x 12" long, so you never have to worry about the skeg repair again.

[OrangeCrush]

Funny how sometimes lacking a bit of nautical vocabulary like "strake" is the only thing holding me back. That sounds like the perfect approach, many thanks.

[UNCIVILIZED]

I'm curious, which dinghy do you have, & what are your thoughts on it? I've wondered about CLC's boats for quite a while, & thought about building one.

On yours, since the fix is in a high wear area, while it was drying out, I'd perhaps get some dynel cloth & epoxy so that I could add some reinforcing overtop of the wood. Including pigmenting a layer or two of the extra material in a skid plate a different color from the cloth & resin covering the entirety of the area being beefed up. That way I'd know when the first outer layer had worn away, down the road, so that I could patch this extra outer layer before things got wet again.

Once the epoxy had cured, I'd prime & paint as normal after removing the amine blush, & scuffing the surface up a bit.

Here's a link to some dynel. Trying it would/will be a switch for me, as opposed to using standard fiberglass & epoxy, or one of the exotic reinforcments like kevlar, or carbon fiber. The writeup on it's interesting. And I gether that it's somewhat akin to polyester cloth used in adding reinforcing skins to wooden surfaces.
Southern Industrial Dynel Laminate
Southern Industrial Flexible Polyester Xynole Fabric

I can't imagine that it would hurt to add a stainless or bronze rubbing strake to the skeg. And if the skeg is wide enough you might want to epoxy bond the fasteners that hold it on in place. That way you'll avoid having water get into the wood. The other thing is that such strakes needn't only be on the boat's centerline. On some dinks you'll see a few on their bottoms running parallel to the one on the keel.


Another word that people sometimes use to describe adding a protective metal strip along the keel or skeg is shoe. And often they run them for a large percentage of the length of the keel, anywhere that it will routinely be in contact with abrasive materials & surfaces. Though it needn't always be metal. As sometimes it makes sense to simply add ectra layers of reinforcement (glass/fabrics or wood) to said area.

If you don't have it already, the book The Gougeon Brothers, On Boat Construction is a good one to have. And you can download it for free via the linked website, along with the WEST System user guides. It's one that's good to have around. Including the section on epoxy bonding fasteners into wood. The Gougeon Brothers on Boat Construction, 5th Edition | Epoxyworks
There are some other good ones below, some of which can be downloaded via the link, ditto (gratis) elsewhere. Books & Videos on Composites, Surfboards, and Boats

[Suijin]

I like Cotemar's idea. You can get the SS strokes in different lengths, single ended or double ended to make it as long as you like. It will also look kinda spiffy.

In my experience anything but metal will just look like crap after a few trips up and down the beach.

[OrangeCrush]

Originally Posted by UNCIVILIZED

I'm curious, which dinghy do you have, & what are your thoughts on it? I've wondered about CLC's boats for quite a while, & thought about building one.

Thanks for the very thorough response, it will take me a while to make a plan but overall I think a epoxy, then paint, then a strake sounds like a nice permanent fix. The idea of adding more strakes on the sides is also intriguing.

It's a Chesapeake Light 8'4" Dinghy. I think the previous owner built it from a kit. Here are some pics... if you know a more specific model name please let me know.

As for performance, I love it. I can't believe how well it rows. My last boat had a 8' Walker Bay plastic dinghy which received jeers from boats when we had more than two guys in it and our gunwales were only an inch above the water. It was also a real pain to row and never kept any momentum. My new dinghy is not much better in terms of overall capacity: one is great, two people is fine back if we sit back to back, three is a bit much but can be done. But boy does it fly! If I get some speed up, she keeps her momentum in a straight line for at least 50-100 feet of distance before needing another stroke.

Even so, I think I need a motor for it before my big trip to Maine and Canada next year. Some of anchorages are nearly a quarter mile from the landing spot at high tide, and with a little current that becomes a real ordeal.

[UNCIVILIZED]

Glad you like your dink. I'm a fan of hard dinks myself, especially given the beatings mine took when I lived aboard. My commute was 1/2nm each way, & 50yds of beach. But my little dory took it like a champ, & only need maint. about once a year, including keel TLC. Rowed great, very stable. Another woody like yours.


On epoxy, I need to get a copy of Russell Brown's book Epoxy Basics. E-Books It's been years since I talked to him, but he does some incredible work, including on his proa, & some AC boats. Plus of course the PT11 dinghy.

[brianlara 3]

All traditional boat builders/ shipwrights (professionals i.e.) in Australia exclusively seal timbers with International Paints product EVERDURE. It is regular 2 part epoxy but formulated ultra thin for max penetration. It is thinner than water when mixed and usually multiple coats are applied until absortion is complete. Normal epoxy doesn't penetrate the fibres to any extent.
If timbers need to be made ultra durable with no chance of rot then Everdure is the most appropriate thing.
For those not wanting to spend the money on Everdure, normal mixed epoxy can be thinned with the approproate thinner, the name of which can be found in the WEST SYSTEM book.
The parent company of International Paints is Dutch company "Akzonobel"
A biece of balsa encapsulated in Everdure will still be perfect 1,000 years after Trump has used the nuclear codes, assuming he will.

[Herb Miller]

There is an article hear that echoes brianlara 3:

Waterproofing Wood

This does work, but intermediate coats do not seem to get past the "tacky" stage. In my case, I put a final full-strength coat, and that did dry fully.

[HopCar]

Here you go, rub strakes. Sea-Dog Rub Strake 304 S.S

[guyrj33]

Gently heating the skeg before applying the epoxy will help expand any trapped air and will lower the viscosity of the epoxy when it's applied. As the skeg cools any air spaces should lower in pressure and pull the epoxy into the wood.
Carbon powder additive will make the epoxy wear longer by reducing friction when the dinghy is dragged on it's skeg.
I favor the addition of a rub strake to the skeg.

[knockabout]

sounds like you have it worked out / clean and dry your skeg / wipe with metho / soak in 180 epoxy (west system would do) / lightly sand once cured / and layer up at least 4 thin strips of woven mat / sanding lightly before each layer/ when you are back to your original skeg length apply your top coat / as suggested above a thin metal plate would save abraiding the skeg on the hard / but then you would have to drill and plug your skeg with epoxy / then small holes to take your skeg armour plate screws enjoy your dinghy

[Rigdaddy]

If you are just going to cover a few inches of the skeg then the strake pieces may be ok, but if you are going to do several feet or if you just like the classic look of brass, then you should go to the Jamestown Distributor site and look at their Solid Back Brass Half Oval stock. I used some to cover the keel and skeg on the 12' cedar strip dinghy that I built this year and was very pleased.

[fatherchronica]

I epoxied with glass over my wooden dinghy keel every few months, a couple layers thick. But you land and drag it up a rocky beach and it would grind to bare would pretty fast. Now I have a 1/4" x 3/4" x 6'6" piece of aluminum screwed on and it has held up well. I am in an area of mostly sandy beaches now though.

[OrangeCrush]

Anybody know where to find longer strakes or lengths of strake-like material? The longest I can find online is 24" but I need closer to 40" (at 3/4" width). Thanks


Sent from my iPhone using Cruisers Sailing Forum