To my mind, there is nothing that looks as good below as a finely finished teak and holly sole. Unfortunately, not all boats come with one. In the case of a 34-footer I’m helping restore, the cabin sole was molded nonskid fiberglass. After years of use the non-skid was chipped, dirty and hard to keep clean.
The fiberglass cabin sole was part of the inner hull liner, bonded in place as part of the basic construction of the hull. So any solution had to work around the existing cabin sole. The sole was also curved in a few areas where it conformed to the shape of the hull.
The traditional cabin sole material is “teak and holly” and comes in the form of plywood. The wide teak strips and narrow holly strips are 1 mm thick veneers bonded to underlying plywood. Nowadays the holly is a tropical hardwood look-alike called Koto.
This plywood is available in several different thicknesses, 6mm, 12mm and 18 mm. When used by itself, the plywood would have to be at least 18mm thick or more to provide adequate stiffness.
The solution chosen for this project was to use 1/2” MDO plywood bonded to the existing cabin sole with 6mm cabin sole plywood bonded to the MDO plywood. MDO plywood was developed for use in outdoor signs, is void free, and waterproof. The combination of 6mm cabin sole plywood over 1/2” MDO plywood would give a very strong and stiff floor over the existing fiberglass sole.
Layout and Design
The first step in the project was to make a sketch of the cabin sole. The edges curved up where the sole followed the curve of the hull and would have to be accommodated in the design and layout. The panels were divided into flat sections, or “facets”, that allowed for the curve of the sole. Spending time figuring this out on paper before cutting the actual plywood saved a lot of labor and money.
Fabrication
As I cut the pieces, I marked both the piece I had just cut and the sketch so the proper location is documented. I was sure to indicate fore and aft directions, too. It sounds simple, but it is better than standing there with epoxy mixed and wondering where this piece goes. I sanded adjacent panels at the proper angle to leave no gaps.
Finishes
At this stage of the project it’s time to consider finishing options. It is much easier to finish as much as possible outside the boat. I wanted all surfaces of the plywood sealed with several coats of epoxy. I have had bad experiences with unsealed plywood wicking up water and rotting.
There are several good epoxy systems out there. Make sure any epoxy system you choose has the additives you need for the jobs at hand. What is more important is how the epoxy is applied, especially to the top surface of the cabin sole plywood.
Bubbles in the epoxy are the enemy of a smooth finish. I mixed the epoxy smoothly, without beating any bubbles in the mix, allowing a little time for any bubbles to break or scoop them out of the mix. The epoxy was applied smoothly with a brush, trying to add as few bubbles as possible.
I gave the plywood two coats of epoxy, paying particular attention to the edges of the panels, as that is where water first tends to wick up. The panels were sanded between each coat making sure there were no lumps or bumps to complicate bonding the panels in place. I also wanted to varnish the top surface to protect it from UV rays, even though it would be inside the cabin.
A word to the wise, not all varnishes are compatible with all epoxies. Read the product literature for both the varnish and the epoxy to ensure compatibility. Then do some test coatings on scrap pieces. The varnish will remain gummy if it is not compatible with the epoxy.
Once the 6mm panels were coated with epoxy and cured, I washed them with water and a cleaning pad to remove any amine blush on the surface. The epoxy surface was then sanded with 220 grit sandpaper to provide a smooth surface with enough roughness to hold the varnish. I applied six coats of a satin varnish to the sole pieces.
Another option is to use the Ultimate Sole products, designed especially for use on cabin soles. The result is a varnish-like finish with excellent non-skid properties.
Installation
I used 60-grit sanding discs to sand the existing fiberglass cabin sole and give the fiberglass some “tooth” to bond to. I vacuumed up all dust and then wiped the sole down with acetone to remove any remaining dirt or grease. SAFETY NOTE: make sure you have adequate ventilation below decks. I use a 20” box fan in the vee-berth hatch running at full speed.
I then dry fitted all the MDO panels back in place, marking the proper location on the fiberglass cabin sole. The panels were bonded in place with epoxy, using colloidal silica additive to make an epoxy mix the consistency of peanut butter. The bottoms and edges of the panels were washed and lightly sanded to eliminate any amine blush and provide a good bonding surface.
I started by bonding the center panel in place. The epoxy was applied to the cabin sole and spread evenly with a notched plastic trowel. The panel was then placed in the epoxy, lined up with the alignment marks and weighted down to ensure good contact with the epoxy. I checked the alignment marks several times as the panels tended to slide around in the wet epoxy.
I took particular care to clean up any squeeze-out from under the panels. Once the center panel was in place, the other panels could then be epoxied in position.
Once all the MDO panels were in place and the epoxy cured, it was time to go over all the surfaces with 80 grit sandpaper. All seams needed to be smooth and even so the 6mm cabin sole would go down smoothly.
I then bonded the center panel of the 6mm cabin sole in place, using the same notched trowel technique to get an even epoxy coating. I again weighted it in place and rechecked the alignment several times. I also took great pains to clean up any errant epoxy drips or squeeze out.
Once the center cabin sole panel had cured, the rest of the sole pieces were epoxied in place. I carefully cleaned up any excess epoxy with paper towels and a small amount of thinner as I didn’t want to harm any of those six coats of varnish.
Conclusion
Was the result worth the trouble? Yes! The cabin sole looks great and, with the epoxy and varnish, should wear like iron. The project took 2 sheets of MDO plywood and two sheets of 6mm cabin sole plywood. No more cold dirty fiberglass cabin sole, just a traditional and warm looking teak and holly sole.
The layout of the cabin sole panels.
An overall view of the fiberglass v-berth cabin sole.
A close up of old cabin sole showing the dirt and dings.
A view of the 6mm Cabin sole pieces epoxied, varnished and ready to install.
Close up of the 6mm Teak and Holly plywood on top of the MDO plywood base.
Whether you are simply working on a minor fiberglass repair, a complete refit, or even a new build, we have all of the boating supplies to complete the job.
http://www.merrittsupply.com
Posted by: merritt Supllies | January 16, 2010 at 03:19 PM
Dear Sir/Madam,
I am looking for some Cabin-Sole plywood’s for my newly build passenger ferry boat, therefore kindly provide me your product catalogue along with other detailed information.
Should you have any other materials to make the finishing of ship cabins, kindly let me know about?
Looking forward to hearing from you and I remain.
Regards
Abdul Hannan Ibrahim
Email: hannan@villatravels.com
Posted by: Island Fibres, Maldives | December 12, 2009 at 04:14 AM