Replacing plywood below the cockpit fiberglass on Oday 28 suggestions please

May 12, 2005
8
- - Burlington, NC
I have a Oday 25 1985 Anniversary Edition I recently purchased. Got the motor out for repairs and decided to repair the plywood below the cockpit floor.The floor is a bit spongy and the plywood has de-laminated. My plan is to remove the Pedestal steering, remove the de-laminated plywood which may require removing the fiberglass lip under the plywood, chipping the plywood out with a combination of putty knife, wood chisel, grinder, screw driver, roofing crowbar and anything else I can think of. Once the bulk of the plywood is gone, I will sand the balance away with a 4" grinder and a sanding disc until the fiberglass is clean. With clean fiberglass I will buy 3/4" marine plywood (I am assuming it is 3/4" thick) and fiberglass the plywood to the fiberglass cockpit floor. Once that glass dries, will fiberglass the under plywood lip back in place. May very well put a layer or two of cloth on the underside of the plywood, effectively sealing it between the cockpit fiberglass and this new fiberglass. I will then redrill the predestal support holes, rebolt it in place with some sealant (this is where the water came from in the beginning).Thats my plan. If you have done this before, can you suggest how I can improve on the method I have outlined. I have done fiberglass work but have not tackled this particular job before so any suggestions or shortcuts appreciated.
 
Mar 1, 2012
2,182
1961 Rhodes Meridian 25 Texas coast
Only the plywood will NOT be 3/4 inch. Doesn't happen here anymore. The actual plywood sizes are metric, because no other country in the world will buy US sized ply. So they CALL it 3/4, but it's actually slightly less, like a 64th.

Welcome to the woodworkers world. I had to resize dado sets for this in my shop.
 
Jan 13, 2009
394
J Boat 92 78 Sandusky
Okay procedure but you will be doing it again someday. Had my sole replaced and FG guy put a solid fiberglass section where there are any sole penetrations. Rock solid 6 years later
 

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Sep 23, 2009
1,475
O'Day 34-At Last Rock Hall, Md
Sounds like a good plan.
Another way would be to run a router around the perimeter of the cockpit floor and remove the upper skin to replace the core.
Another way would be to simply fill the area with epoxy and rebed the pedistal with buytl tape.
I used the third approach three years ago and it is still solid so far. At the same time I replaced the rusted out idler wheel bracket and powder coated the pedistal which made it better than new.
Good luck.
 
Jun 21, 2007
2,117
Hunter Cherubini 36_80-82 Sausalito / San Francisco Bay
Many years ago, more than I care to remember, I wrote and posted my cockpit sole repair experiences. And later added some variations to the theme as the topic arose again later by other poster. I found my posts again using this site's search function. I cut-and-pasted them as below. My own approach was per njlarry's. That is go at it "from the top".

The cut-and-paste has resulted in a disjointed presentation here. But read through. Might give you a few ideas for alternatives before you start your project. In particular, read the "Alternative Idea" section below. It might be possible not to even replace the core. If the plywood hasn't rotted, and its the bonding between the laminations that has failed, injecting thinned epoxy, then vibrating, inject more, might reinforce adequately without needing to removing the top or bottom skins. A lot less time and effort.
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Plywood Cockpit Core in Cherubini 1980 H36

I did repair this past summer the cockpit sole section under/around the pedestal of my 1980 Cherubini H36. The core was a mosaic of individual plywood squares. The plywood itself was not rotted and was still firmly attached to the upper and lower fiberglass skins. But probably because of years of H20 ingress, the glue holding the plywood layers together had failed. Took several hours with a sharp wood chisel/hammer and then an orbital sander/grinder to get the all plywood off of the fiberglass. I'm a newbie to sailboat maintenance, so best to make your own assessment about the following which is how I went about my repair. I'm sure that others have better methods, but maybe you can find some nuggets of info that might help. I don't know if the Cherubini 37 cockpit sole is constructed similar to the Cherubini 36. On my 36, after removing the pedestal and other mounted hardware from the sole, I used a cutting bit on my dremel tool to neatly cut around the top layer of fiberglass at the interface of the non-skid and smooth surface. Then I was able to peel off the top section... (didn't come off easy). Cutting out the bottom from the limited space underneath the cockpit floor seemed just too difficult. I removed all the old plywood core and roughed up the new mating surfaces. I put duct tape over the holes into which the pedestal and grab rail bolts went, both on the top and bottom skins. Maybe not necessary, but from underneath, I attached several long/straight 2x4's using deck screws through the wood into the lower fiberglass skin. I did this to bring the lower skin to a reasonably flat condition since the pedestal and steering sheaves are mounted in this area. I cut off the portion of the screws that protruded up through the fiberglass. Later, after the epoxy work had been completed, from the bottom I was able remove the screws and then the 2x4's. I drilled lots of 1/2" holes in the replacement wood. Then I flooded the bottom with West Systems' epoxy and layed in the new wood. Pressed it down until epoxy oozed up through the holes. Then flooded over the wood with more epoxy. Then brushed a layer of epoxy to the underside of the top skin to wet it. Then layed and centered the top skin on. Jiggled it around for a while so the epoxy would flow and adhere. An issue was deciding how much epoxy was needed to flood the space so that all plywood/fiberglass would be mated everywhere, but that lots epoxy wouldn't ooze out. The fact that the boat was not completely level also complicated. I put heavy stuff on the top skin to keep it compressed and level on the new core. After the epoxy had set up, but was not yet rock hard, I shaved back the high spots that had oozed out. I found that having some syringes on hand loaded with still wet epoxy was useful to neatly fill the gaps where epoxy had not filled to the top. Since the orignal cut to remove the top was at the smooth/non-skid interface, and with careful shaving the excess epoxy, and sanding with a small block, and with two-part polyurethane paint to finish it all off, the repair is not noticeable at all unless really trying to notice it. One item that I would vary if I ever do this repair again (hope not), is that I should have made the core area around the pedestal maybe about 1/8" thicker than at the edges of the repair area. After a rain or washdown, I have noted a small 1/16" deep puddle in the center around part of the pedestal base. If the center thickness hd been bowed up a bit, the water would run off and into the cockpit drain. regards, Rardi

Pedestal Removal and Cockpit Sole Core Repair - Cherubini Hunters

I have a 1980 Cherubini Hunter 36. A couple of summers ago I posted some info about my cockpit sole repair. I have gone sailing on the boat about 150-200 times since the repair. No signs yet of any gaps or stress cracks around the repaired seam on the cockpit floor and the pedestal is firm and rigid instead of loose and swaying in the previously spongy sole. (Just a note about working with epoxy. Make sure to wear protective gloves at all times. You may not have a reaction to epoxy yet, but exposure is cummulative. Once one becomes sensitive, then the rashes and other skin conditions can be very difficult to treat. Read all the manufacturer's instructions and safety info.)

Below is a cut-and-paste of my first my post about my repair experience. Then a copy of a post about my experience removing/reinstalling the Yacht Specialties Pedestal on my boat. There will be more than one way to skin this cat. So the last section below is yet another possible alternative.


An Alternative Cockpit Sole Repair Idea


(Just re-reading the following today July 18, instead of cutting "trenches" maybe large many large 1"-1.5" holes cutting into the top layer in a pleasing geometric pattern would be another way of getting lots of epoxy into the core)

I've done the spongy sole fix project on my 1980 Hunter 36 and have posted my experience on a few occasions. Looks like you are thinking outside the box for alternative ways. The core material sandwiched between the top and bottom FRP cockpit floor layers on my boat (which won't necessarily be the same as your 5-year later vintage) was a checkerboard of individual plywood squares (about 4" sides) laid in. This plywood was wet (water dripped out when I removed the pedestal and guard rail bolts from their holes). But when I did peel off the top skin, I found that the plywood was not at all rotted. The wood grain itself was still like new solid. (It had a green color so maybe it had been pressure treated?) And it was still very firmly glued to the fiberglass skin. Instead, the glue bonds between the plywood layers themselves had delaminated and were oozing with water. If your core is the same plywood and has failed in the same way as mine, then perhaps, as you are thinking, there might be a way around completely removing the top skin. I do think that if the core is compromised, adding another layer of flooring might improve things a bit, but the floor will still flex and if the core continues to degrade, it will need to be fixed right at some point. I'm not an expert, but I'm a reasonably creative DIY'er. The following might be something I might have tried on my project in hindsight. I'm thinking of the layout/construction of the cockpit sole on my boat, which may not be applicable to yours. Also please get other opinions. I don't think the below would be an optimal solution, but as you seem to looking to avoid removing the whole sole skin and rebuilding, here's my idea: - When you remove the pedestal, there will be a large hole and you should be able to readily see the type of core material and its condition. If it is plywood and the wood looks to be only separated continue to read below. If the core is rotted, my inclination is that removing the skin and replacing the whole core and then rebuilding is the way to go. - In a transverse direction (across the cockpit floor rather than in the fore/aft direction), cut out say a 1" wide strip of the upper (non-skid section) of the cockpit floor, say about 4-6" aft of where the sandwiched cored section start. Cut all the way through the wood to the lower fiberglass skin, but not into it. Don't go all the way to the beam-to-beam edge of the cored area. Leave say 1-2". Remove the top skin and the wood core from the cut. There will be a 1" wide trench in the floor. Again look at the core to determine its condition. If the wood is good but delaminated... - Then another 6-8" aft of the first strip, cut another transverse trench, and then more trenches until the aft section of the floor is reached. Think out the spacing of the trenches so that they don't intersect with the pedestal and guard rail bolt holes. And the last cut aft isn't right at the edge. - At this stage, there will be a number of transverse trenches in through the non-skid surface of the sole. But the majority of the sole's surface will still have undisturbed non-skid FRP in place. All the uncut non-skid top FRP skin will leave plenty structural strength to the floor. - Let the core dry completely... this can take days or more. Obviously can't be rained on. From underneath, think about drilling some holes into the bottom skin at the very lowest point aft to that any pools of water that remain can drain. - Cover the non-skid surface between the trenches with tape to keep it free of epoxy mess. Starting with the forward-most trench (which presumably will be up slope from the others), fill it with West Systems type epoxy. I think that it is possible to thin the mixture a bit so it will be a somewhat more "runny"; which you would need to check with the manufacturer. From within the trench and the next aft trench, stick in a pry bar here-and-there to work around to flex and open up the delaminated wood, which will help whisk the epoxy into more of the gaps/voids than just plain gravity. Lay in the trench some sort of reinforcing rod or hardwood to give some added transverse strength (and so you won't need as much epoxy). Maybe put some weighted object over the undisturbed non-skin surface to help compress the epoxy into voids and gaps. - Carry on until all the trenches are done. - You might have to go back several times as the epoxy level in each trench is likely to sink as the epoxy works its way into the voids. - After the epoxy sets up, then mix some more epoxy with West Systems' colloidal silica thickener and add a final coat into the trenches so that its level with the non-skid surface. If the thickness of the mixture is correct, it can be dimpled to a rough looking surface. - Remove the protective tape from the undisturbed non-skid surface. Finish the entire cockpit floor with the non-skid paint of your choice. If the trenches were cut nicely and uniformly, even though their new surface texture will be different than the existing non skid, I would think they would have the effect of intentional and pleasing design rather than collateral damage of badly executed repair job. - Undoubtedly there will be variations on this theme depending on your situation, imagination and reaction of other advisors. One variation would be to initially cut only the first two trenches. Go through the drying and epoxy fill steps to verify that the epoxy does in fact whisk into and repair the delaminations. If not then move on to "Plan B" (what ever that might be!) - Don Casey in his book "Sailboat Hull and Deck Repair" does cite a deck delamination repair method of drilling lots holes in the top skin in/around a delaminated area, and after drying out, filling the holes with epoxy. (See the book for details.) But this is for a delamination between the fiberglass skin and the wood with no other damage or rot to the core wood. I think this method would have only minimal effect in the case of delaminated layers of the plywood. Hence my "trench" idea. - Plan on lots of hours no matter which way you go. I spent better part of a week to repair my sole. Your idea of trying to drill long horizontal holes for reinforcing rods and then laying up new fiberglass, and final refinishing would also be time consuming I would expect. And another advantage of leaving the top skin largely undisturbed is that the big hole for the pedestal and all the other bolt holes are still where they were, making reassembly that much easier.




Yacht Specialties - I took Mine Apart


..... this past summer I completely removed and reinstalled the Yacht Specialties pedestal on my 1980 Cherubini 36. The steering mechanism was operating fine, but its removal was necessary to repair the cockpit sole's water saturated wood core through which the pedestal is fastened. By the picture that Ian McGain posted, the mechanism looks to be the same that is on my boat. As already posted by Grizz, although Yacht Specialities is defunct, Edson is a source of info. On the web page Link submitted by author you can find a pdf file entitled, ".... Planning Installation and Maintenance Guide." Its for their newer products, but it looks like many of the principles are similar to the Yacht Specialties system. Hopefully your cable just became loose over time and finally it slipped out the quadrant cable channels or off the sheaves that angle the cable from the pedestal to the quadrant. But if you do need to take your system apart here's some info about my experience: I did find it useful take close-up photos and make notes of each section before disassembly so that I would have better chance of later remembering how to put it back together. I can’t give you step-by-step guidelines, since I didn’t retain my notes or pictures. But how it fit back together is rather logical. Took a few hours to remove the system and reassembly took me a full afternoon. You probably will be dealing only the the cable/chain/sprocket system, but if the whole pedestal needs be removed, throttle and transmission cables need to be removed/re-attached from the engine side as well. (About a loose cable, before my cockpit sole repair, my cable was somewhat looser than I would have expected as normal ... "not to loose, not too tight". Perhaps this was because as the wood core rotted/delaminated between the upper and lower fiber-glass skin, the pedestal was depressed downward from normal which loosened the tension? My tip-off about the core damage was that the top of the pedestal/wheel assembly would move from side an inch or two when pushed ... it didn't feel solid.) One thing that I did do wrong on my first refitting of the steering cable is that I hadn't noticed that the cable crosses over itself inside the pedestal. That is: If you are standing to the aft of the pedestal looking forward, the chain/cable that drops from the starboard side of wheel chain sprocket crosses over to port sheave that angles the vertical drop of cable back to the quadrant. The other side crosses from port to the starboard sheave. Also although its not readily noticeable, one of sheaves is a bit forward of the other. This is so the cable sides don’t rub against each other as they cross inside the pedestal. This routing inside my boat was hard to see on my boat, but I probably would have missed the cross-over even if it was right in front of me. So best as you can, try to observe and record the routing from the chain sprocket to the sheaves and also the routing quadrant/attach points before you take the steering chain/cable off. If the cable doesn’t cross over itself inside the pedestal, the steering works, but turn the wheel to port and the boat goes right and vice-versa. While I was at it, another item that caught my attention was the molded plastic housing into which the gear shift and throttle handles are set. This is the piece that Ian McGain photographed and was unable to remove the four screws from. I had better luck as my screws came out. While I was researching Yacht Specialties pedestals in preparation for my disassembly project, I read somewhere (probably deep in this forum’s archives) that people have had problems with the plastic housing breaking inside where the shift and throttle lever shafts and cables are anchored to the housing. The accounts cite that if a cable anchor or throttle handle breaks free inside, one might not be able to (say) shift out of forward into reverse. Or the throttle might get stuck at full (or idle). Or the broken-loose part could jam in the steering chain. Any of which would be a heart stopper for sure if the failure occurred (say) after committing to the final turn into a berth. When I had my part removed from the pedestal, I did discover the beginnings of a stress crack near one of the cable anchor points. The web references said that this pedestal part is no longer available and a casting shop would have to custom-make a replacement. I decided instead to reinforce all the potentially suspect areas by encasing/epoxying them with custom bent u-channels I made from stainless steel sheet metal. Then I poured in lots of West Systems epoxy all around to ensure that nothing could possibly ever break apart.