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Deck and stringer repairs
Submitted By: fixb52s
Date Created: 02-28-2008
Description: I knew the rear decking aft of the firewall needed to be replaced. I was only going to replace just these sections. The deck forward of the aft seat was already replaced. I saw the deck under the rear seat was falling through, so I decided to pull it out. After finding the deck was installed by someone who really doesn't know the meaning of a solid boat, I decided to rip it all out. I was not happy to find mushy stringer wood and bulkheads. They are being properly replaced and reglassed to restore the structure. Many boats from this era were made with wooden stringers and decks wrapped with fiberglass. Over the years, water gets into them through holes and rots the wood out. There are many boats out there that were improperly repaired because it is so much easier to throw new wood in and screw it all together. It looks great with new carpet, and actually feels solid. It is what is not seen under the deck that is important though. Fiberglass really is not difficult to work with, but is very messy. Fiberglassing in new stringers and the deck is the only proper way to repair the structure. This boat will wander out in Tampa Bay and I don't want a questionable structure under my feet. While all the hard work will not be seen in the end product, it is important to do it right. I also spoke to the retired Ocala boat repair guy who replaced the transom and engine mount in this boat. It was done in 2001 because the engine was flopping around. The owner at that time did not want to spring for new stringers and deck that needed to be replaced at that time. At least I have been saved a LOT of work. To replace the transom, the engine would have to come out, and that is something I am not in the mood to do.
Related Projects: 1986 Chris Craft Scorpion 178 BR
    (Deck and stringer repairs)
    Sea trial
    Hull restoration
Tools / Materials: Go to the Boating Store

Old plywood deck out
This is some of the decking that was torn out. It appears it was replaced already once before the previous owner got his paws on it. I found old gobs of sealant and old unmatched paint everywhere. The previous owner must have decided to replace it again from the rear seat up with this. The factory decking bonds to the hull is about 8 inches from the gunwales. This unpainted 3/4 inch plywood was installed butting up to the gunwales so it was higher than what it need to be. Wood shims (scraps) were installed on top of the stringers to raise the support, and 2X4s were placed directly on top of the fuel tank to support the middle. I did not get any photos of this, and I kick myself. It was all screwed together and screwed to the stringers. Not only is this stupid, it is not safe. Since the sides of the deck were not bonded to the hull on the sides, the boat would not support the forces imposed while underway. The deck is designed to distribute the loads along with the stringers. It appears this was all fresh work. Who knows how long the boat was used with this setup. At least there is no stress cracks in the hull, so all is good.

This is what was used for a forward bulkhead. Someone did not have the concept of what makes a strong boat. A 2X4 was just sitting on the hull on one side. It was cut where the fuel hoses came through and did not tie to any side stringers. In fact, there are no stringers here. It appears they were cut out at one time. The inner stringers forward of the fuel tank were found to be mush. This boat would have probably twisted under extreme turning and rough seas.
Nice bulkhead

Another view
The front stringer caps were worn away, exposing the top of the wood. This could be from them never being properly attached to the deck in a previous repair. The hull flexing would move the deck from side to side, gradually grinding the fiberglass away. The fuel tank has a few pinhole leaks on the top and the hose is brittle. The tank is going to a shop for repairs and the hose must be replaced. Fuel fumes under the deck is VERY BAD. Check for some photos on the net and see what fire will do to fiberglass.

Here is what was left of the front bulkhead after removing the tank and the old "repair". The mush that used to be wood was chipped/scooped and vaccumed out, leaving the fiberglass sides.
Front bulkhead cleaned

Rear bulkhead
The rear was a little better, but the wood was all broken up and wet. A lot of garbage was under the fuel tank and it was clogging the rear bulkhead drain, trapping water under it in the bilge. The tank sits above the hull, allowing any water to drain to the rear where the bilge pump is located.

Like the front, it too was chipped and cleaned, leaving the fiberglass sides. The fiberglass is still solid, and will be left in. It will be trimmed down prior to adding new glass. Note here the front engine mount. It is also very solid and does not have to be replaced. Since it is good, the engine will stay in place.
Rear bulkhead cleaned

Front stringers
The front stringers are now being cored out. The wood was reinforced with resin poured into holes drilled into the tops of the stringers at one time. All this did was helped solidify the tops of the stringers, but did nothing to the remaining wood. The top of the wood was semi solid, but the rest of it was mush. The stringers under the bow were also cored from the rear. I could have removed the cap to get it from above, but since I could reach everything, I left it in place. I pulled a cap before, and really don't want to do that again.

What was thought to be good turned out looking like this. It was dug out to the rear where dry solid wood was found just behind the rear bulkhead. For some reason, the wood is extremely solid from the rear bulkhead back. The transom is also very solid and does not have to be replaced. Core checks done to the stringers and transom were done to check the condition.
Side stringer mess

More mess
What was once solid wood 22 years ago is now this. Got to love these old boats. This is only a very small sample of what came out. A lot of trash bags went to the curb containing this. The Shop Vac did a good job of sucking up a lot, and the wood kind of broke up into dust in it.

All of the work was being done outside (got to love the Florida weather). Rain is in the forcast for the next 5 days so the cars were kicked out of the garage. I wish this garage was 3 feet deeper. The boat JUST fit this way. If I didn't have so much crap on the side, I could have put it in sideways. My next house WILL have a nice deep garage/shop.
Rain in the forcast

All the old foam is coming out. It has some water in it, but not bad at all. It had to be removed to glass the stringers in. I seen foam totally soaked before, and it adds weight.

About 3 40 gallon trash bags of foam went to the curb. New 2 lb. foam will replace the old after the structure is restored. One note here: It seemed that I caught a cold the day after pulling this out. Mold? Maybe.
Foam gone

Stringer channels trimmed
New stringers were cut and fitted. The old channels are being trimmed to bed them down. Normally, they would be totally cut out at the bottom, but I am leaving most of it there because it is in good shape, and will only reinforce the new glass "caps" that will cover the new wood, forming the solid stringers. If I was to do this again, I would remove the foam first then cut the stringers about 1" from the hull. It would have been much faster. Live and learn.

New stringers were made from 3/4 cabinet plywood. The channels were sanded and cleaned up. The new stringers and bulkheads were bedded in the channels with polyurethane adhesive. At the rear, a "Z" cut was made to splice the old with the new.
New wood bedded in

Glassed in
The stringers and bulkheads are glassed in. The surrounding fiberglass that the new glass would bond to was ground and cleaned with acetone. This created a lot of dust and makes one itch. For glass, .75 oz matt was first used, followed with 24 oz roven cloth. 2 layers of mat and woven were used on the stringers, and one layer was used on the bulkheads. this is where it gets really messy, and the fumes will take you to the moon if you are not careful. 3 gallons of resin was used for all of this. mixing the resin and hardner is a hit or miss depending on the temp. I had a few batches gell up within 10 minutes, and others that took over 1 hour. After all the glass work was done, the boat came out of the garage and sat in the sun. These stringers are now strong again.

The boy and I took the boat out to the lake to check for leaks. Before pouring foam and replacing the deck, I want to ensure the hull is leak free. We launched it and tied it to the dock. It was not a busy day, and there are 4 ramps, so we were not in anyone's way.
Out to the lake

Oh snap
Found a leak on the starboard side of the transom. While it is not too bad, it would leak directly into a closed foamed area. Other than that, the hull seemed well sealed up. At least there was no water coming from the transom around the lower unit.

The speedometer pick up looked like this. It seems it was replaced before, and the old holes were not sealed. Better to find and repair these little things now than later when the foam gets wet.
Leak source

After cleaning the holes, they were sealed with Marine Tex. After this was dry new holes were drilled and the pick up was screwed back on with expanding sealant on the screws. The hose support mid way up the transom was also repaired the same way. The hose coming through the transom was sealed with 3M sealant.

Back to the lake. I had the boat in the water for about 1/2 hour and everything inside was bone dry. I would have pulled it earlier, but the kids decided to swim around and have some fun. Besides checking for leaks, this is one huge morale booster. After a lot of work time spent, itching from fiberglass and getting generally worn down and frustrated, it is good to see it on the water. It gives a lot of motivation to continue this project. Move on to the deck!
Leak check good!

New wood for the deck
1/2 inch cabinet grade plywood is being used for the deck. All the pieces were carefully measured and cut. A pattern for the sides were made from heavy brown paper and transfered to the ply. The panel above the fuel tank is a seperate piece and will be secured to 2X2s that will be attached to the stringers and bulkheads. The reason for this is if the tank has to come out in the future, this panel will be removed for access. Too many decks are one piece with the floor and have to be cut to remove the tank.

The holes for the fuel tank sender access panel and ski locker were cut out now, prior to fiberglassing it all in. with the fitting complete, the panels will be final shaped and sanded. The bottom of the deck will be coated with resin for waterproofing prior to it being secured down.
Another shot

Fuel hose
The fuel filler hose and return were just foamed in at the factory. I was not impressed with this.

I ran 3 PVC tubes for the hoses and tank wiring. This way, the hose can be pulled out if required without ripping the floor out. The original hose lasted since 1986, but like to overbuild to help out any future maintenance.
New hose installed

Fun with foam
I never used this stuff before so I mixed up some and went to town. This stuff kicks in about 30 seconds after mixing, so the working time is very quick. I learned that I can pour some, let it rise, then pour more if needed. The excess above the deck level can be "sawed" flush with a saw.

I went a little crazy and now have to trim a lot. All this took just over 1 kit (2 ea 1 gallon part A and B). If I knew what I was doing, I could have done it with just 1 kit and could have taken the rest back for the $91 I paid. Live and learn, but at least I have enough foam left over for my 1960 Starcraft whenever I get to it.

All the foam is trimmed flush with the stringers. The hull is ready for the deck! At this point of the project, I have been at it for a month, putting about 130 hours in it so far. Yesterday I was watching the boats out at Bradenton Beach and hoping I will be joining them soon.

All the decking ply is sanded down and final shaped. It is ready for a coat of resin on the back side. The edges were beveled where they have a little more contact with the hull.
Decking sanded

Deck going in
After sealing the bottom of the deck ply, it is screwed and bonded down. Poly adhesive is used on the hull and stringers, and screws also hold it to the stringers. The edges were held down with some scrap wood until the adhesive set. I put the ski locker door on for the fun of it.

The floor ends were faired to the hull with resin mixed with micro bubbles. Everything was once again ground and cleaned (I really am hating life with all this grinding). The first layer of 1.5 oz mat is down. The heavier mat sucks the resin up and I ended up running out. Another trip to the store (they know my first name now). The neighbor's yard was getting mowed and some dirt and grass got into this, so it will have to be cleaned out first.
Glassing deck

Almost done
The layer of cloth is in. Other than trimming the edges and glassing the fuel tank cover piece, this deck is done. It is sitting outside in the sun to fully cure.

All the deck is glassed in. The fuel panel will be screwed down to a support base and sealed up prior to the carpet going down. I also have a little more clean up around the sides. There is still some of the thick gooey sealant from a previous repair that needs to come out.
Deck complete

A little paint
After some time cleaning up the old glue on the gunwales (after removing the old carpet), removing the remaining "goo" on the side deck and sanding the new decking, I painted it all with Rustolleum oil based paint. This step is not really needed, but I went ahead anyhow to help seal it up a little more. It will all be covered up with carpet so it will never be seen. The small blocks on the bulkhead are temporary supports for the fuel tank access panel. After the tank goes back in the real frame will be added. A note about the gunwales: At the factory, the sides were sprayed with foam, and a thin layer of glass was installed over this.

Now the new fuel tank is in the center panel can go in. Of course, I did a leak check prior to installing the panel.
Fuel tank in

Carpet in, deck complete
New carpet was glued in the gunwales and deck. The fuel tank access door and the ski locker panel support are also screwed in with stanless steel screws sealed with 3M 4200 sealant. After 3 monts of work, the hidden stringers and deck are now fully complete.

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