after removing my old Ideal windless I discovered that at the drive shaft hole the core in my fore deck is water damaged and the deck has pulled away. After sounding the deck with a mallet I am going to need repair approx. 3 sft. of deck. INTRIM was built in 76, does anyone out there know if the foredeck core is plywood, balsa or something else. I want to have all the proper ingredients on site BEFORE I cut into the deck. Thanks
The core appears to be balsa. That is what I found on Phantom when doing work there.
This is as good a time as any for me to post pictures of my deckhouse core repair. Before you launch into any major deck core repair work you must ask yourself a couple of questions: First, are you concerned about loosing your nonskid pattern. My answer was no. With this being third major hole in my deck skin, any hope of preserving the nonskid pattern was over. Plus the enamel paint that was already applied to the deck by a PO had to be ground off everywhere. And Second: are you going to stay with polyester resin or just bite the bullet and go epoxy. I can't think of any reason to stick with polyester resin especially considering that you no longer care about saving the nonskid. Great, you just made the job 10x's easier with these two decisions.
Using an oscillating saw remove the skin and all the rotted core. Getting this all to dry out after being water logged for 20+ years may take some work with a heat gun. Notice the two 1" holes aimed to help with this process.
(http://i1121.photobucket.com/albums/l505/banjoband/deckhouse1.jpg)
Someone asked about balsa core. My opinion unless your laying up a new boat with lots of curves you don't need or even want balsa. Balsa is weak, absorbs water like a sponge and is candy to termites. On a flat deck, plywood from home depot which comes in three thicknesses was the answer for this job.
(http://i1121.photobucket.com/albums/l505/banjoband/deckhouse2.jpg)
I only use one kind of cloth and that's the bi axial stuff. It's thick like mat and strong like weave. Its the only kind of cloth you will ever need.
(http://i1121.photobucket.com/albums/l505/banjoband/deckhouse3.jpg)
I skipped a couple of steps which were the next layer of plywood, the top layer of cloth and epoxy resin. While that top layer of cloth and epoxy is wet, put the skin back on. I used drywall screws to pull it down flush around the seams. When that is hard remove the drywall screws, grind a vee along the seam and fill the seem with a silica structural epoxy mix. When that's done spackle the whole thing flat with epoxy and colloidal shere mix that can be faired with a sander.
(http://i1121.photobucket.com/albums/l505/banjoband/deckhouse4.jpg)
Here is the finished deck. The enamel is gone and the deck was painted with epoxy prime coat. This is your barrier layer between the old gel coat non skin and your new bulletproof epoxy deck. With a salt shaker I add coarse nonskid to the epoxy primecoat after its rolled on. Us alot and lay down a beach. Brush or vacuum the loose stuff after the epoxy is hard and start applying your epoxy color coat. I like to bury the nonskid in 2+ layers of epoxy color coat. That cuts down on the road rash incidents.
(http://i1121.photobucket.com/albums/l505/banjoband/deckhouse5.jpg)
sv "Tartanic" Pearson Ketch old #6
Nice write up Pete! Thanx very much for the info.
Divinycell or any of the closed cell foam products used in boat building are superior to balsa and plywood. But expensive, and if you can't pick it up locally the freight charges can double the price.
Plus if there are screws or bolts that hold the repaired area in compression, I'd preffer a hunk of plywood in there.
http://boatdesign.net/articles/foam-core-properties/index.htm
Pete,
Looks like you did a great job. Questions...
1) I am assuming the water got in to the balsa from fasteners on the mast collar ring?
2) Did you remove deck/core all the way to the end of the wet core?
3) Was there some sort of band in the core that went across the boat just forward of the dorade box?
Thanks...
Dale Tanski
Dale,
There is probably not a Peason out there that has this problem to some degree. When you eye across the deck, the area by the mast collar and tensioing rod should be the highest spot you see.
I'm pretty sure this failure started many years ago with water getting in around the tensioning rod hole. At some point the core around the tensioning rod failed and collapsed either from over tensioning of normal deck pumping. That also caused a crack in the skin which created a visible low spot for water to sit and migrate. It had also rotted the wooden collar that covers the mast hole inside the cabin. It had been leaking there for decades. Which also explains the rotted steel mast step.
There is a lower structural rib that goes starboard to port in line with the mast. You can see that as the bump-out in the head liner down below. Water never got to what from the piture looks like the 3rd layer of balsa core which you can see in the picture as the bottom layer of the rib. The second layer of balsa which appears to be also part of this rib was rotted around the mast along with the top layer of balsa which extents over the entire deck.
Foornote: The Pearson house is structurally very stout. Recall that it was only after this repair that I jacked the mast with 2 ton bottle jacks sitting on the deck. With the mast lifted to the point were that standing rigging was once again tight (with probably 1/3 ton of pressure pushing down), I measured 1/2" compression of the deck from the keel to the headliner. And thankfully during this stress test, I never heard a creek or worse a crack.
There were additional voids I cleared out mostly to the port side and an maybe 5 " to the starboard. I knew there would be because I cut the skin slightly less that what appeared to be the affected area through soundings. I dug out rot til I hit hard wood. Then I cut plywood pieces to go in there and the larger pieces were cut oversize to go into the voids like tongue and groove. They were wrapped with glass wetted down with epoxy and driven in there. I filed other voids through holes in the skin to make the repair contiguous.
Incidentally I have repaired loose or squeaky deck skin simply by drilling 1/4 holes and pumping in 105 that has some silica fibers added to it. It works like rivets.
Pete
Pete,
All good info. I ask the question about a cross stiffener because my deck has a noticeable band crossing the deck about 6" or so wide. I see the underdeck support but this is visible in the nonskid. I was curious if you found anything in the upper deck structure that would cause this. It became very noticeable when I repainted the nonskid. I will look for a picture that shows the hump.
Thanks again & good sailing!
Dale Tanski
Dale,
My Pearson was probably part of the pilot run, hull#6. This part of the assembly may have changed over time. From what I saw it looked as if this rib consisting of 3 layers of balsa core 6-7" wide might have been layed up and preformed in a jig. Then that piece was put into the layup of the deck and remaining pieces of core placed forward and aft from that initial piece. When the rib was glued together in the jig it created a very good moisture barrier between the them. And they probably sealed the sides with polyester resin in the process. This may explain why the 3 rd (bottom) layer remained dry.
The balsa core they used was typical balsa endgrain glued to 1/16 plywood, which is what allows it to bend, but in only one direction of course. The balsa evaporated but the plywood base holding it together was solid. So the plywood you see in the picture is the bottom of whats left of the second layer of balsa core. It remained glued to the exposed balsa endgrain of the bottom layer, miraculously.
No rib is visible to me from the topside on my 365. Perhaps on later assemblies instead of pre-forming the part in a jig they formed all 3 layers in place with clamps or weights to save time. This shortcut left impressions visible on the topside especially if the skin lay-up was not completely cured. Your deck was probably layed up on a Friday before the 3 day of the 4th of July weekend. Hows that for detective work?
Pete
Pete,
Here is the band (lower left corner). I never really noticed it until I painted the deck. I accept the concept of "not completely curred" but I would think this would be a problem if it was removed from the mold too early.
Dale
(http://i153.photobucket.com/albums/s233/dtskibo/Maruska-starboarddeck_zpsd0b84047.jpg)
I noticed that on Shadow's deck (for sale on Yacht World) she has the same band across the deck at the mast... Interesting.
How many of you have the band?
Dale
Dale, I have no band but I have hull #18. Allen
OK, so now we have found out that some boats do and some boats don't have the band. I am personally relieved as I was beginning to think my boat was the only one, and because of this disfigurement, I was ready to cut her up for scrap. I am going to call the self help group I was attending and cancel out for the additional six weeks of therapy.
Now the other question, what did the good people at Pearson do differently between the haves and the have nots and when did they start doing it? Some where between hull #18 and #35 Pearson started to so something different and I can't help but wonder what it was???? My hull is five older than Sailaway being hull #40.
I will say when I read Pete's statement regarding water in the core material "There is probably not a Pearson out there that has this problem to some degree." I mentally agreed but thought... around the mast area? I have no signs of delam or water in the core at the mast pass through, but that is my boat and I guess I am lucky in that regard, but I wonder if they did something in the structure to minimize the possibility of that occurring. If the band was a reinforcing of some nature to minimize movement of the deck at that location, this could explain why some boats experience water issues in that location and others don't.
Garner, your boat is much younger, do you have the band? All the rest of you out there, give it a look and let us know, band or no band?
Thanks...
Dale
Dale,
I suspect that the good engineers at Grumman Allied Boat Works knew their statics, and understood the problem. Consider what occurs when under beam reach in heavy wind. The tension on the rigging forces the hull to compress laterally. This loosens the rigging. This lateral compression also causes the deck to heave upward. At this point the only thing keeping the mast from popping out of the step is that tensioning rod. Yikes!
So although the deck is very strong in compression (downward), the balsa core is probably not that good under tension which comes into play in the upward vector. Perhaps some work was done to strengthen the deck/hull to resist laterall compression. This would relieve the tension under sail on the tensioning rod.
Pete
Dale,
1982 367, no band, but do have teak plywood running for and aft on foredeck about 12" to 18" wide for a core material.
I don't think there is an inherent problem with water intrusion causing soft decks houses or soft decks.I believe the problem is poor matinees.Some of these boats are over 35 years old.How many times have these boats changed hands?On my own boat the deck house is solid no soft spots around the mast or anywhere else.But I have taken great care to keep the water out.The problems I have had is on the foredeck. The P.O. had a windless installed,the yard didn't properly seal the work.The factory installed hauls pipe got minor water intrusion around it.Next I bent a station on the bow pulpit that caused the base to crack the glass,so for a temporary fix I silicone the crack.It was almost two years before I did a proper repair.The good thing is that the repairs aren't difficult just labor intense.It is probably time to do something about your slick nonskid anyway. As for the tention rod being the only thing that keeps the mast in the step I can't buy that.If that were the case I would never leave the dock. Allen
I hit the wrong key in spell check,it wouldn't let me change it.The correct word should be maintenance.Sorry Allen (but I did go to public schools)
Dale,
I can report hull #69 has no band. However, reading what may lie ahead (SV Jeanie - new to me last fall - has yet to be fully inspected) I would like to sign up for the therapy sessions you gave up.
I have yet to play with this epoxy stuff - anywhere on the boat - and dread the thought of cutting holes here and there. I envision bands, humps, horrible surface finish post my work so plan to start 'epoxy' fun inside the port water tank. I see anti slosh baffles that may have at one time been epoxied to the bottom of the tank, now sitting about 1/2" above that. How bad can I mess up the finish and shine in there! :)
Back to the thread; I am installing a new windlass so will report at that time ('future - maybe later this month') what deck/core issues I find when drilling and filling up there. I was thinking I had 3/4" solid fiberglass, guess not.
Ok guys, I'll weigh in. Hull #284. No visible band on the cabintop, but seems to be a one inch thick by six inch wide "beam" molded on the inside across the cabintop liner at the mast. I assume this is to accommodate the actual thicker laminate in the deck. Do the older boats have this feature? Jim
Jim,
Yes my hull number 40 has that inner liner band.
Dale
I realize it's been 7+ years since this post but I've appreciated the discussion. We have the "banding" or extruded areas on both topdecks and below (#297) and I've wondered if it had a specific purpose and if so, what it was. Interesting to know it's included on some 365/7s but not on others.
Cheers