Starting 87 SN Floor/Stinger Repair

farmer wrote: Skibum,are you using pine for the secondary stringers and doug fir for the main stringers?

I purchased the wood at a local lumber store. Used the fir 2"x8" for the main stringers. Using #2 pine for the secondaries. Perhaps the same as what came out. The big difference is that I have applied epoxy resin and multiple layers of gla$$ and resin to each individual piece comprising the secondary stringers, then a$$embled them with epoxy and gla$$. I just finished bedding the observer side with 403 filler. The final preparation step will be application of an epoxy resin with fairing compound to smooth out the lines and accentuate the water channels.

The last stringer is installed. It is bonded on a bed of resin and two layers of 10oz gla$$. I used resin and 4" then 8" wide strips along the seams with the hull this morning. Once cured, I'll come back and bead the seam with 403 filler and resin. The picture wont post, I'll try again.

Used a level and a hand plane to adjust the height of the secondary stringer so that the stringer is 1/4" lower than the edge of the floor. This will allow water to move toward the bilge once the new floor is complete. The driver side stinger will be cured by morning so I can do the same on that side.

Started by cutting a cardboard template to fit in the bilge. Used two pieces of 1/2" plywood. Applied epoxy resin and two layers of 10oz gla$$. When cured I laminated them together with resin and 10oz gla$$. Used a jig saw followed by a drill operated drum sander to make the holes. Set it into the hull on three layers of chopped strand and gla$$ed it into place.

Cleaned up the battery box. Replaced the drain fitting. Used 5200 on the connections at the battery box. Installed new vent hoses. Cleaned the 4" pipe and set everything in place.

Used cup holders as thru hull fittings for the vents. Just cut out the bottom. For each thru hull fitting (thru hull into the bilge) I used epoxy and chopped strand mat inside the holes with epoxy and gla$$ all around.

When I removed the floor to begin construction I found major water saturation in this area. The new bulkhead is much thicker and totally encased in epoxy resin and gla$$. Each hose is clamped, each connection sealed, and every fitting gla$$ed to prevent future problems in this area.

Poured 4lb foam. Started in the bilge area. After several pours I worked my way up into the bulkhead.

SkiBum -
The 403 filler info is from the material data sheet.The pictures of the job you are doing ; speak for them selves. You're a craftsman!   

Once I sanded the foam I applied a thick layer of resin. Used a layer of chopped strand mat followed by two layers of 10oz gla$$ to repair this area. On top I did the same where I cut two holes to facilitate removal of foam and application of the new stuff.

For the floor under the bow I added more foam and cut a gentle slope from bow toward the bilge to help prevent water from pooling.

Also used the hand plane and level to trim the driver side secondary stringer to the right height.

This is the concept I am using for the floor. The origional floor was several layers of gla$$ and resin over foam.

I am using 3 ply, 1/4" floor under layment. The bottom of the 3 ply is laminated with 10oz gla$$ and resin. All of the edges are saturated with resin. The top of the 3 ply is epoxy resin with chopped strand mat followed by 10oz gla$$. Both the top and bottom are laminated and cured before application.

The floor piece rests on the foam and is bonded to the secondary stringers on an epoxy resin mixed with 2-3 layers of chopped strand mat. Once cured, the edge next to the hull is bonded using 2", 4", then 8" strips of 10oz with epoxy resin. The same for where the floor and the stringer meet.

This will provide a water tight, strong bond between the stringer, floor, and hull.

The piece for under the bow is curing on the bottom right now. Hopefully I can apply the gla$$ to the top tonight and it will be ready for installation in the morning.

SkiBum
        You do pretty work ! No offence about the filler - just the facts. It’s very difficult to make change without a$$igning blame. I’ve got my motor & trans ready to go in (look under general “ how fast is fast “) I ripped up the carpet & floor to replace the foam . Can’t wait to crank-it. In your profile your Army I was Navy
now silly service w / USMC with all the hours your putting in the Marines would say Sleep is for the Weak. Keep at it !!!

Hollywood wrote: Bill, you got the double "s"-$$ thing going on with the file name.

Thanks Hollywood. I would have beaten my head against the wall for hours on end and still never figured it out.

This is just more of planing the secondary stringers to the correct height. Despite my best efforts I could not yield a precise pattern from the old ones. Anyhow, this is the best way to get the right height .

Alan,
This is what the boat looked like when I started. When she looks that good again I'll call this project complete. I try to post only useful photos. I would be happy to put together a summary of the project for others to use as a reference. I learned everything I know from this site. I'll put the photos from the blooper reel in the off topic forum.

Waterdog,
I wish I would have known earlier about the 403 filler. That is good information that people who look to this site need to know. Marines - Army, hell, when the bullets start flying it's all the same: set a base of fire and manuever.

This is the floor panel under the dash. Once again I under estimated the difficulty level of what appeared to be a simple operation. I intentionally left a sloping downward curve from the bow to the bilge. This meant I had to use weights on the floor panel while leaving enough room to gla$$ around the edges and do all of this under the bow. To make it funner, I keep the garage temp at 80 deg for the epoxy to cure properly. End state, the floor panel is installed. Alternated chopped strand 2" wide, 10oz 4" wide, and 10oz 8" wide for a good bond. Filleted the edges to keep water from standing at the edges. Also, right at the center of the bow the CC boys randomly sprayed chopped strand creating small humps that would be great for holding water. I removed these clusters, sanded the area, and filleted all the way down to the floor. My philosophy, if you can see it, it can get wet.

Besides obscene wakes at slower speeds another symptom the 87 SN displayed before I started this project was excessive vibration. When I removed the carpet I discovered that on the pa$$enger side from the front of the bow back to the front seat the floor was separated from the hull. Both secondary stringers were separated from the hull as well.

When I removed the floor I cut it a safe distance from the hull. Today, I went back and trimmed along the edge of the hull to remove the lip from the floor. The pieces in the foreground are what I cut away. Some foam was still attached. If you look closely you can see the final cut along the hull.

In some places the floor was separating away from the hull already. This is a delicate operation - not much suited for an infantryman. Anyway, I managed not to cut into the hull. I must still sand about a foot up the side of the hull and clean it in preparation of the new floor.

SkiBum,You're making great progress.I'd like to thank you for all the great pictures. They will be a big help to any of us who will go through this process in the future.
                     
               Farmer   

SkiBum, I know Im not the only one who finds this project interesting. Thanks again for contributing your project to this site.

I have performed a floor/string repair on a much smaller scale than yours, documented in this thread, in case you havent seen it. It has a good discussion on my approach to the floor.

I used a method that emulated the original floor construction of gla$$ over foam. Alternating epoxy mat and 6 oz gla$$, it took me 7 layers to build up to the original floor thickness of 1/8". This was by far the least enjoyable part of the whole miserable project. In comparison, the stringer repair and foam pouring were easy- almost enjoyable.

I went through a lot of gla$$ and about 3 gallons of epoxy resin. I would imagine you would use closer to 8-10 gallons. I know if I were replacing the entire floor, I would stick with your original approach of using the wood.

Hopefully someone with much more experience will share their opinion!

I know, another boring photo, sorry. My focus has turned to working on the bilge in preparation of the new floor. I applied a thick layer of fairing compound to the stringers, channel between stringers, and bilge. I intend to eventually produce a smooth as gla$$ bilge where all of the water flows toward the drain plug. Again, an attempt to keep the new floor and stringers dry for more than 20 years this time.

I had planned to hold off so I would not scuff up the bilge while I do the floor. I just can't stand having free time to work on the boat but not get anything done. No better way to use that time than sanding fibergla$$.

I was staring aimlessly at the boat trying to think of what to do next. That is when I realized that I needed to make te braces that are perpendicular to the secondary stringers. I went back to the photos from deconstruction to remember how to put it back together. Thought these were more interesting than photos of sanding.

The floor is gla$$ed over this foam with 1"x2" supports that rest on the foam and are attached to the secondary stringers


The entire front of the floor was no longer attached to the hull from the observer seat foreward.

Remember in my installation I used two 1/2" pieces of plywood lamintated and saturated with resin. In this photo you can see that at the bottom of the hull the entire area is not connected to the hull. Water in the bilge can seep through into the foam below the battery box. And it did!