Jeff- all the core in the deck and also the liner, is end-grain balsa, not plywood. Ccompared to plywood, it's much lighter, less prone to delamination, but unfortunately more prone to dry rot. Keep everything sealed (hardware) and it can't dry rot.
The cabin sole, however, is NOT cored. We bonded the sole directly to the bottom of the hull. We would wet out several layers of fiberglass mat, set the liner and weight it down with about a thousand pounds of sandbags. Nothing in there to rot, but a delamination obviously is possible. Jerry jerrymontgomery.org ----- Original Message ----- From: "RandyG" <[EMAIL PROTECTED]> To: "For and about Montgomery Sailboats" <[email protected]> Sent: Friday, April 06, 2007 8:56 AM Subject: RE: M_Boats: M-17 Spongy Floor Jeff, We had a similar situation with a portion of the cockpit floor on our 1988 M17. A large area between the mainsheet traveler and companion way began to feel spongy shortly after we replaced our mainsheet traveler track. Upon close examination I found the top layer of fiberglass had separated from the plywood core. The cockpit floor is a fiberglass-plywood-fiberglass sandwich construction. I don't know, but maybe the cabin floor is constructed in the same way. In our case, the plywood core was dry and fine. I talked with Jerry, and one other owner who was experiencing the same problem. In our case the solution turned out to be a straight forward and inexpensive repair. - Using the trailer tongue jack I raised the bow of the boat. - Drilled 2 small holes in the area of cockpit floor where the separation had occurred, in the forward most portion of the area. The idea was to use gravity to allow the epoxy to flow towards the stern. The hole size matched to tip size of a 60cc medical syringe. - Taped off an area around the drilled holes to catch any excess epoxy, and using a medical syringe dripped penetrating epoxy into the holes for several hours. - After a period of time, by pressing down on the voided area of the cockpit floor I could feel the stickiness of the epoxy as it touched the plywood core. - Placed several 8"x8"x16" cement block on top of the floor to compress the top fiberglass layer onto the plywood core. And continued the epoxy drip. - Eventually the epoxy stopped flowing as the void became full. Based on the amount of epoxy used, I would speculate that some of the epoxy was absorbed by the plywood core . I let everything sit for several days. And then patched the drilled holes with gelcoat patch. After a year of use the floor seems 100% solid. The key ingredient in this repair is in using penetrating epoxy. The stuff will find its way into every void, nook and cranny, and takes 24 hours to setup. (amazing stuff). It has the consistency of about 10 weight motor oil. Amazing stuff, and relatively inexpensive. While the problem you are describing is not quite the same, I hope this information is helpful. Having had our centerboard out, I am trying to think how water might get up into the area you are describing, and can't come up with anything. Sincerely, Randy Graves M17 #410 ________________________________ From: [EMAIL PROTECTED] on behalf of Jeff Royce Sent: Fri 4/6/2007 7:36 AM To: For and about Montgomery Sailboats Subject: M_Boats: M-17 Spongy Floor Hi All, I am an avid reader of the Monty e-mails but a very infrequent participant. I am what one may call a casual sailer with little knowledge of manufacture. As I was removing my porta-potty for cleaning (always an enjoyable experience) I noticed that the floor in the cabin (roughly 3" or so from the v-berth and back toward the companionway hatch about 4 inches or so, about a 4" circle right in the middle of the boat) was a bit spongy. It would move down with the pressure of my foot. I felt like, even though my gentle pressure would not break through at this time, that perhaps the time was coming when it would. There is a little inspection hatch right there at the bottom of the v-berth and when i opened it it seemed damp inside but not wet. I took her out last about 2 weeks ago. Questions arise such as 1) is there a marine plywood subfloor under the fiberglass? 2) is the water getting in from the centerboard well? 3) could the same sponginess be found on the other side (the hull)? 4) what is the expense of a repair? 5) is one needed now or can one simply wait until it gets worse? or 6) my favorite one... is this nothing to worry about and should i just keep sailing? Jeff Royce Cameron Park, CA M-17 Hull #366 1982 Vintage _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats ---------------------------------------------------------------------------- ---- > _______________________________________________ > http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats > ---------------------------------------------------------------------------- ---- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.26/746 - Release Date: 4/4/2007 1:09 PM _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
