Core or no core?

[garyf]

Is there some sort of guide or summary re: which parts of different models are cored or not? Any good way to know before you drill or cut? I'm picking up little bits and pieces of info all over the place and I guess it's adding to my confusion more than not.

- I've seen in more than one place that the "sides" are not cored... is that the side of the cabin?

- I've seen varying answers about the bulkhead between the cabin and cockpit (I hope I'm using the correct terms - I'm talking about the "wall" on the back of the cabin where the door is)... I've seen people say it's wood, I've seen other answers - cored / not cored... so I guess it might depend on the model too.

- It seems pretty safe to say that the hull and transom areas are cored... is that all the way up to (and including) the rails?

- Are the cored areas all approximately the same thickness? If so, what should that thickness be? I'm looking at the screw holes through the roof of the cabin that hold the handrails up top (and the electronics shelf) for example - the screw holes are very small, so it's tough to tell for sure if there's any core in there... but if there IS, then it's very thin... too thin, IMO, to Dremel away any balsa or anything. I guess I could hit it with some epoxy, but the screw holes are almost too small to do that effectively.

I've studied these forums quite a bit... but now I have a pile of stuff to install and so on and... it's "real" now - lol. I guess the most conservative approach with installing things is to glue something to the surface them screw into that? I get that from a core integrity standpoint, but in the long run it seems like you'll eventually have to deal with the hunk of "whatever" you glued on as well??

MOST of the things I need to install have pretty good examples in here - what a great resource this has become over the years! I haven't found examples for a couple of things yet, although I'm sure they exist somewhere - I'd like to install a ganged set of four rod/tool holders to the back of the bulkhead for example... to hold various things like boat hook, net, a rod or two, whatever. Surely someone has done this? I haven't decided if I should just screw... or glue and screw, etc.

 

[thataway]

For basically all of the boats (in some more recent models there is foam rather than balsa core):

Bottom of the hull is cored from transom to the forward V berth bulkhead. From there forward on the bottom is solid glass. The core varies but at least 3/4" to 1 1/2" thick. Glass on inner side is about 1/8" thick and outer between 1/4 and 3/8" thick.

Transom is cored with plywood or balsa.

The sides of the boat (vertical) are not cored--solid glass from 3/8" to 1/4" thick

The aft bulkhead is about 3/4" balsa core--but the boat up until the mid 90's (and I don't know exactly what year) were a Marine ply with vinyl overlay--similar to what was used for the interior. Since you have a 1991 boat that is probably very similar to the 1993 c Dory 22 I owned--and is the plywood. You will also have the teak hand rails. You will have smaller wood screws than the SS which are bolted on with thru bolts.

The deck is mostly cored with 3/4" balsa core.

The cabin top is where it may vary. Generally the outer part is cored, and the center may or may not be cored. For my 2003 25 the center was not cored, on my 2007 it is cored. My best recollection is that my 1993 C Dory 22 had cored outer parts of the cabin top.

My experience with the hand rails is that the same bolts or screws held the shelf in place as the rails. Were SS railings, there were flat head machine screws, with finish washers and they were either 1/4" or 5/16" diameter. The inner hand rails were also held in place with those bolts where the inner hand rails were specified.