Yes John there are many of the very old boats that have foam core and the fiberglass 1/2-rounds for deck strength. I know of some folks that have had issues with the foam core delaminating - the difference is there is no rot like balsa but the repair is the same as the damaged area needs to be rebuilt. Balsa gets a bad rep but the issue is really lack of owner maintenance and incorrect care. :: Dave Scobie :: SV SWALLOW - https://sv-swallow.com :: Montgomery 6'8" #650 :: Truck camper - https://truckpopupcamper.wordpress.com/ :: Ramblings - https://scoobsramblings.wordpress.com/ :: former M17 owner #375 SWEET PEA - https://m17-375.com/ <http://www.m17-375.webs.com/> :: former M15 owner #288 - http://www.freewebs.com/m15-name-scred On Mon, Jun 22, 2020 at 1:02 PM John Schinnerer via montgomery_boats < montgomery_boats@mailman.xmission.com> wrote:
On 6/22/20 12:14 PM, Dave Scobie wrote: ...
most of the horizontal portions of the deck and cockpit have balsa core. some of the older M17s also have a thin plywood core on the cabin wall port and starboard of the companionway.
Seems YMMV a fair bit on some of this with early M17's.
My 'early' M17 #38, 1974, has no balsa core anywhere. For which I am quite glad, since I'll never have to deal with rotting balsa core, which would have happened by now on a boat this old, especially given some prior owner used @&#^$%!! silicone to "seal" various things, and, some of the deck fittings appeared to have no OEM bedding at all. Which doesn't cause any problem but possible seepage to the inside, if there's no core to rot or to trap water and cause de-lamination. Anyhow...
Cockpit has foam core underneath on some horizontal parts.
Cabin sides/top and foredeck have glassed half-tube reinforcement crosswise on the underside. On the cabin top it runs fairly close to fore and aft sides of chainplates and mast step. On the foredeck there are two half-tubes, spaced out what looks like an appropriate distance structurally (my foredeck is plenty solid, anyhow). The cabin layup also gets significantly thicker around the chainplates/mast step area. I could see this when I replaced the window glazing and had the frames out. Aft cabin wall has no core, thin ply or otherwise.
Apparently this was a plenty solid layup & reinforcing method, since the boat has had no structural failures in 46 years (though I don't know how much hard use it got with prior owners).
Those of you with M17s of similar vintage...same construction, or different?
cheers, John