Re: My Oh My, why not to use PT wood without glass or resin..
OnDaRVR,
Thank you for chiming in, I have come to understand you are a sage with things that float and go...
First things first..
How do you know this was PT wood that rotted? Not that it can't, I just want to know how you identified it as PT.
The soft section of the floor wasn't so much rotted as it was disintegrated, I pulled chunks of wood out that was obviously identifiable as wood, but had COMPLETELY delaminated (the layers of the bad wood were totally separate as if NO glue had ever been there, and even the better sections of the bad section of floor had delaminated although they had not disintegrated..)
ALL the hardware used to attach the bad section of floor to the stringers was off the shelf pnumatic driven steel staples, no screws or nails, just stupid little brad staples... the areas around these staples had turned black, and the black staining had run down the stringers where this section of the floor was residing (even under the glass) the nailed edges were in relatively good condition, other than the staining and the delaminating of the flooring.
My understanding of the stains is this is a result of a galvanic reaction of the CCA in the 20 year old plywood meeting the untreated steel staples... but COULD just be the old staples rotting away.
Exterior and marine grade ply are not treated to be rot resistant, they just use water resistant glue, although depending on the type of wood used in the marine ply (many options) it may be more naturally resistant.
Going to 3/4 when it was originally 3/8 is a waste of money and will add unwanted weight.
In my case the weight isn't necessarily unwanted, one PO had repowered in 03 to a 300HP Alpha gen 2 setup, the engine setup is roughly 150lbs more than the old setup.. this is causing high bow while anchored and some odd trim needs at slow speeds (I have added trim tabs to allow me to trim the bow down WITHOUT using the outdrive trim). I NEED more weight, especially in the bow, but over all more weight won?t hurt me.. the boat is LIGHT (20?6? dry weight 2600 and change) and I run a light gear load (heaviest piece being a cooler full of ice and drinks). I figure I could add 1000 pounds or so and still have room for gear and people (normal day out is 500lbs or so in people)..
The 3/4 ply would only add 200 pounds or so, at or below the water line, which as far as stability is concerned should be a good thing, but should be far more rigid than the boat was delivered, add in the improvements in glass application and I should be sitting pretty?
BTW with a Quicksilver 23P SS prop I am topping 70MPH in the engines efficiency range (4600RPM) but only doing so at 8/10ts throttle...and have plane on demand from idle, I do need a new prop, and can go down to a 21 if I need to adjust for added weight when all is said and done with the refit..
I realize I might be coming across as argumentative, or cocky, so please if there are reasons for me to NOT use the 3/4 other than the added weight feel free to comment, but at this point I believe added weight is a GOOD thing in my case? NOW if I need to replace the stringers, I will fully redesign the underfloor supporting structure to allow me to use a lighter deck without having to worry about it buckling as the current 3/8 flooring is doing?
My initial feel for the project is Chaparral cut some corners when originally building the boat, the HULL is great, and well built, but only using glass to seal the wood on ONE side is chincy at best? even the front seating areas only had glass and resin on one side? the port side bow seat had almost completely rotted from the INSIDE of the seating supports where there was no glass or resin, but at least the wood wasn?t delaminated like the bad section of floor I took out? the front 12 inches of floor (under the bow seating, but still part of the deck) had NO glass to the hull, the glass ended even with the face of the seating area?
