Dorade Box Design Failure -

More
14 years 6 months ago #232 by Andrew Schoenberg
Hello All Fellow Whitby Owners,
I bought Possum Magic In April of last year and the survey indicated wet core on the coach roof.
I was getting water leaks inside the cabin dripping into either the drawers or along the cabin roof
sides. I have now found the cause of the water leaks and the wet coach roof core. The two
Dorade boxes on the coach roof were improperly designed and installed on my hull 148. I have
now removed about 2ftx4ft from both port and starboard sides including both dorade boxes and
have found substantial flaws in the original design and installation resulting in core destruction due
to water intrusion. It is very clear looking at the stains on the lower skin that the water came in
thru the bottom of the dorade box which is a false bottom poorly bonded laminate and migrated
down the slope of the cabin roof to the sides and into the cabin. Using a Fein Multimaster and
Rockwell sonicrafter (by the way a very interesting comparison) and both wonderful tools, I have
corrected the problem. I plan on installing two nicro solar vents in place of the two dorade vents.
I would be more than happy to share with anyone interested the picture of the deconstruction
of the cabin roof. PLEASE take a look at your dorade boxes, the leeward side of mine had the
drain holes 1/4 inch above the deck surface so that water always stagnated inside the box. This
simple issue was probably the main root to water ingress over 30 years.
It is also very interesting to see that even wet core has good adhesion to the top and bottom
skins of the deck. Only saturated core was completely devoid of structural integrity. Using a
good moisture meter and drilling test holes I was able to locate the worst of the water intrusion
and I have now mapped my decks for moisture to use as a tracking system for future evaluations.
If you want more info or pics you can contact me at: aschoenb@netzero.net

Sisu

Please Log in or Create an account to join the conversation.

More
13 years 8 months ago #555 by Alan Lindsey
I would love to see photos of this. I have looked into our dorades a few times and noticed how the water would just pool and not drain out the holes. This might explain some of our mysterious water intrusion. Did you peel back the top skin and replace the core?

Thanks,

Scott

S/V Honu Lele
Kemah, Texas
Hull# 141

Please Log in or Create an account to join the conversation.

More
13 years 8 months ago #556 by Andrew Schoenberg
Hi Scott

I removed the top skin completely - would only come off in small sections - none salvageable.
The core was black under the dorades and you could trace a trail from the black core under
the dorades to the edge of the coach roof by the line of black core. All the core in these
areas were removed and replaced with new balsa and then epoxy glassed back into place.
I will try to attach a picture for you.
Andy

Sisu

Please Log in or Create an account to join the conversation.

More
13 years 8 months ago #590 by Alan Lindsey
Hi Andy,

Upon further inspection I found wet core around our bow dorade box. As with yours the bottom of the box is below deck allowing water to pool in the box. Add to that the fact that the corners have mysterious deep cracks where the laminates meet I suspect water has an unimpeded access to the core. I removed the thru-hull to the cabin interior and found black rotted away core material. Unfortunately I am just finishing up painting the deck or I would do some destructive surgery as you did to replace the wet core and make the dorade removable.

My remedy was to add a layer of 1/2'' okume plywood epoxied to the floor of the dorade with lots of filler in the corners to raise the floor of the dorade above the deck level. This should force all the water to drain instead of pool. I am also going to take this opportunity to enlarge the cabin air hole. I was thinking of using 4'' PVC pipe with female threads to allow a plug to be inserted in rough wet weather.

Scott

S/V Honu Lele
Kemah, Texas
Hull# 141

Please Log in or Create an account to join the conversation.

More
13 years 8 months ago #602 by Guy C. Holbrook III
Hi Andy,
Catching up with this thread long after your post. Very interested in your solution. I have what seems to be a similar situation with my starboard dorade. With your experience do you think that a non-viscous epoxy adhesive solution sluiced into the box area might be a solution? I have been pondering this for some time and thought this winter during layup I would visit this problem.
Thanks for your thoughts.
Guy

Please Log in or Create an account to join the conversation.

More
13 years 7 months ago #608 by tom jones
capns: i would like to rekindle this discussion re: dorades. perhaps those who did the repairs successfully could update us. we are currently searching for the cause of a starboard roof leak down the cabin side and into the cabin at the nav area. after rebedding the hatches and deck hardware around the mast and checking ports we are narrowing it down to the dorades. any update would be appreciated. thanks tom BlueJacket Brewer 12.8.

Please Log in or Create an account to join the conversation.

Time to create page: 0.190 seconds
Powered by Kunena Forum