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Cowl Vents and Leaky Dorade Boxes

Gline

Member I
I just finished up a 2 week long project and wanted to thank Christian Williams and Footrope for their detailed posts! I've attached a pics of the finished job (in hindsight I should have taken pics of the damage and the repair process).

The 2 forward dorade boxes on my 1984 e38 were in bad shape. Years of water and termites had damaged the plywood flooring (I can't believe Ericson left exposed plywood). The previous owner had sealed up the cowl vent covers and the small drain hole with silicone, but as a live aboard he usually had hatches or port lights open for ventilation. I don't live aboard and I badly wanted some passive airflow, so it was time to get dirty. I know I could have used solar vents or something else modern, but I like the idea of keeping things original.

Note: I've only owned sail boats for about 8 years, so my repair skills and knowledge are basic DIY. Hopefully I didn't make too many mistakes!

Dorade Box Fix
Step 1: Remove the Cowl vent base. This allowed me to fit my hands more easily into the boxes.
Step 2: Strip old paint on floor of the dorade box (a PO had attempted to fix this leak years ago with paint). Wipe with acetone after paint striper.
Step 3: Dig out rotten plywood. Some came out easy. Some wood had a rock hard surface (maybe a previous layer of epoxy from PO) but was soft underneath likely from termites, so in those areas I drilled small holes.
Step 4: Prep 12 ounces of West System unthickened epoxy per dorade box. Footrope was spot on with the 12 ounces (one box soaked up all 12 and the other 10 ounces). Inject epoxy into the drilled holes. Pour epoxy onto the floor of the dorade box and brush around so that it covers all the surfaces and fills the voids left behind by the rotten wood. Gravity pulled the epoxy toward the drain hole, so I did my best to brush away from that low spot to minimize future drilling out of that hole. Christian recommend using something like a rubber tube to keep that hole clear (I wish I would have done that, oops).
Step 5: (Could maybe skip this step) Fair the uneven spots with 407 thickened epoxy. I then put a small amount of unthickened epoxy over those areas to seal up any small holes in the fairing epoxy (recommend by West System tech support, but probably overkill).
Step 6: Drill out the drain holes. I was able to keep one free during the epoxy step, but the other needed drilling. This step could be avoided with some better foresight.
Step 7: Wet sand to remove amine blush.
Step 8: Create a UV protection for the epoxy, I know there is no direct sunlight on this but I don't want to do this repair ever again! I primed with 2 coats Interlux Primekot and then used 2 coats interlux brightside.
Step 9: Have a beer (maybe 2)

Cowl Vent
I went with the Vetus Jerry Style Stainless Cowl Vent. These vents are pretty slick and you can add a little screen on the inside (which I need to keep the termites away). The only issue (I was pretty annoyed at this point because I thought the epoxy work was done), is that the base for these is a male ring that is too small for the existing opening. I used some epoxy thickened with some 406 and chopped fiber glass to decrease the size of the opening. I then created UV protection for that epoxy (maybe overkill). I then drilled the new holes and bedded the fancy new vents with butyl tape.

I may be crazy as I love doing boat repair, but this job wasn't very fun. The biggest nuisance is the small awkward space and having to contiourt your hands. I could have finished this faster than 2 weeks, but work gets in the way plus somedays were sailing days and not work days.

Thanks again fellas for all your posts! I would not have been able to complete this job without all the info on these forums! Time to go sailing!!




Cowl 1.jpgCowl 2.jpg
 

Pats

Member I
Wow, looks good , I too have recently discovered that we been having a leak in the same spot on my 38-200. All the wood is saturated and seems to be weeping to the foam in my head liner from the unsealed vent in the cabin top . Also seems the protective stainless steel railings are leaking a bit . Looks like the previous owner attempted to do something .

I agree with UV protecting the epoxy , as I can see the previous work . The epoxy that the former owner did is all cracked and falling apart .

Im not excited about this , just because of the small space in the Dorade box .

thanks for the your post , and others as this has given me good in-sight on repair ideas .
Little annoying because we live aboard and our saloon is in shambles . And of course now I actually have to deal with the crap zippers that I have been ignoring .
 

Pats

Member I
Big hands

Okay , so I’ve managed to clean out the “storage box” pretty good , but now I’m starting on the Dorade box, lol, my hands are big , any tips on digging out the old epoxy/ gel coat any tools you found useful ?
I was hoping not doing this but I broke a piece off and the wood is saturated underneath , doesn’t seem to be rotten , but it’s wet under the epoxy .

74993366-049C-4D6A-A995-97DC0C4C038F.jpg

EE755F07-3DD4-44D3-9BD4-76ACD392F3B6.jpg
 

footrope

Contributing Partner
Blogs Author
If you can get the dorade box floors somewhat dried out, pouring in penetrating epoxy (CPES) or possibly Git-Rot (I've not used that) could be used to stabilize the wood and fill some crevices. I used the CPES in all three spaces and still wasn't totally successful in sealing up the storage area. it takes time to dry, that's for sure. This year I put a 1/4" Star Board cover over the storage area. That seems to be working. The dorade stand pipe in your second picture seems to be pretty solid although I only see a tiny bit. Re-bedding the dorade rings and sealing around the base of the cowls will help. I have threaded bronze cowl rings and I can put covers in them over the winter, with grease or Lanacote on the threads. I have also covered them with the inverted dinghy and that kept the area dry over the recent winters when I've been trying to get all that dried out.

The "tripod" guard bases should definitely be re-bedded, but you'll have to deal with the headliner. If your upholstery skills are up to the task it is possible to take down the headliner partially and get it back up. My tripod backing plates and bolts were quite rusty. There may be staples going up into underside of the house top (everywhere) and into the core that will let water drip onto the headliner once the core is wet. That fix is hard and I don't have a sure-fire fix.

The ring around the mast base is also a place to look for leaks into the core. I cleaned the deck and sealed around the ring at the deck, and then re-sealed the left 9 out of the 18 through bolts, all with 3M 4200. I will get to the rest of them eventually. The round cover forward of your mast should be checked, if it screws into the deck. Also the small rectangular plate aft of the mast, which is a fitting for a cable that holds the house top down. You have a vertical cable aft of the mast that runs to the plate under the floor? Mine wasn't leaking but it was easy to re-bed.

Hope that helps. I have big hands too and I don't know of any shortcuts for the access problems.
 

tenders

Innocent Bystander
I’ve found a cheap ($20 after coupon) Harbor Freight oscillating saw paired with a better ($10 at Home Depot) bimetallic blade to be very effective in disrupting old plywood or balsa core. The blades come in many different lengths depending on how deeply you need to go into the core.

These are designed for plunge cutting, but they don’t take up much space and are very useful tools for lots of boat projects. A decent blade will shear off the undesired length of a bolt past a nut with ease, even stainless.
 

Gline

Member I
Sadly I found no tool to fit well into the box, the space is so small. But you may not need to remove too much of the old epoxy. I'm not the most experienced, but I'd think the old epoxy could become the floor to your new epoxy. Also, drill a few holes into the old epoxy so you can inject epoxy into the rotted wood below.

Would be nice to dry out the wood, easier said than done. Maybe put one of the small Star Brite No Damp Dehumdifier thingys into each box, seal it up with duct tape and leave for a few days. No clue if this will really dry out the wood, but maybe...
 

mizunoman101

Member I
I know I am late to this discussion, but we simply could not stop the leaks in our forward Dorade box...We are summer liveaboards, so the leaks were just a huge pain, staining the teak around the starboard bulkhead and also in the head. We had a custom sunbrella cover made that snaps over the top of the two dorade vents. Yeah, it stops the airflow, but it's simple to put it on when we know rain is in the forecast. When I am more motivated, I will dig it all out as you did.
 

Pats

Member I
I know I am late to this discussion, but we simply could not stop the leaks in our forward Dorade box...We are summer liveaboards, so the leaks were just a huge pain, staining the teak around the starboard bulkhead and also in the head. We had a custom sunbrella cover made that snaps over the top of the two dorade vents. Yeah, it stops the airflow, but it's simple to put it on when we know rain is in the forecast. When I am more motivated, I will dig it all out as you did.
Ya it Was a horrible project . But I think I got it . It stopped leaking for the time I had it . Sold it about 6 months later .

I ended up clearing out as much of the old bad cracked epoxy as I could and sucked it out with a vacuum, I put a hair dryer in each hole and let it run for hours and did it a few times over a couple of days to make sure the core was dry . I also had the whole thing covered for about a month to make sure that’s where the water was coming from. Thankfully it wasn’t rotten anywhere that I could check.

because it was winter when I did it , Canadian eh ;) , I couldn’t use any penetrating products because if I remember correctly the temp range for curing wasn’t right .
In the end I used a west systems 205 fast hardener , but I did it at low out side temperature, which I feel it allowed time for it to soak in the wood abit making sure the epoxy containers were room temp when I mixed them
( found some good info online about it)
. Over the next couple days I did a few coats and felt I got everything sealed . And then after I painted it with a polyurethane marine paint . When I put the epoxy on I didn’t just do the bottom . I did everything inside the holes I could reach this way I felt it made a water tight bond all around . Same with the paint . As where the previous owner I think just poured epoxy in and hoped for the best.
Only thing I feel I may have not done well on was the drain holes but I have a feeling they weren’t draining well from the last attempt anyways . I ended up putting a wire up them and forcing some silicone up the drain hole . Then after all was done using the wire to pull and help remove the silicone after . I did find a little standing water inside but I would drain slowly with rocking of the boat . The water was mostly me testing to see if I was leaking down below. Put new vents on and put a marine sealant around the the bottom of the base for the new vents .

good luck on your project. .
 

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mizunoman101

Member I
The first picture in your series (with the hair dryer) ... that oval area on mine is completely fiberglassed... you cannot see any exposed wood.
 

Pats

Member I
The first picture in your series (with the hair dryer) ... that oval area on mine is completely fiberglassed... you cannot see any exposed wood.
That’s a bonus , mine was all cracked and looked terrible . It was the easiest area to deal with . The two side vent areas were a lot more difficult.
 
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