CD27 squishy cockpit sole

[mikebikeboy]

Cockpit sole, especially around where the rudder shaft comes through, has become increasingly squishy over the last couple of years.

I saw the video Atom did of re-coring a cockpit sole on a CD27, and he glued a sheet of plywood to the underside of the sole to stiffen it up and keep it flat before cutting into it. I'm not doing to big refit so there's no way I can get under there to glue a piece of plywood there, it's just too small and crammed.

My original plan was to re-core with some scrap divinycell I had left over from the integral water tank build. But now I'm thinking perhaps I should use something stiffer since I will not be able to glue the sheet of plywood to the underside of the cockpit sole. G10? Pretty heavy stuff though.

Also, I am thinking to do the job in two stages, first the after section and then the forward section, to make things a bit easier .

Any suggestions of core material? I do not want to use plywood. Or, do you think the divinycell will be sufficient even without the extra support of a sheet of plywood below the sole.

Thanks for any insights.

[atomvoyager]

You can do it in two sections and don't need the plywood underneath for stiffness. I used it mainly because I had access and wanted to hold the shape of the bottom skin flat once the top layer and core were removed to make it easier to have a flat result. 1/2" divinycell should be adequate for you without plywood underneath but you should probably add a layer of fiberglass on top the bottom layer before adding core and level it if it's wavy with West System 406 or equivalent, then set in the core and then reuse the top skins. Once it cures, walk on it and if there is minor flexing you don't like you can add a couple layers of glass on top or screw in a 1x2 wood stringer in a couple places below.

No need for heavy expensive G10 although you could use slightly less heavy Coosa. I prefer divinycell for this because it's easier to work with, lighter and cheaper and the core doesn't need more density or stiffness since that is mostly achieved by top and bottom skins.

[mikebikeboy]

Thanks for the great information Atom. Appreciate it very much. I will post pictures of the progress.

Couple more questions for you:

1) When removing the tiller, is there any fear of losing the rudder or something slipping down and away? The boat is in the water so I'd hope not to have something like that happen.

2) Are there any considerations when working around the rudder post? I'm not sure what that situation looks like yet but want to make sure I don't mess anything up with regards to that.

[atomvoyager]

The rudder is help up by the shoe on the keel so no problem there.

Working around the rudder shaft tube is as it appears in the video and I can't think of anything to add there. For others following the thread, the footwell recore is shown beginning at 10:45 in this video:

https://www.youtube.com/watch?v=xde6yRTvO2M

[mikebikeboy]

Great to know, thanks.

[CapnK]

Hello Mike - When I rebuilt the cockpit sole of my A-30 I used foam as a core, pre-cut to fit while the old squishy sole was still in place.
On removal of the old cored area, I found that there to be a 'lip' of solid glass at the bottom corner which was 3/4-1" wide, all around the perimeter. Makes sense that it would be there, and it fortuitously seemed 'ready made' to use as support for the new, so...

I glassed the 1" EPS core both sides with CSM and finish cloth to make it suitably stiff, dropped it in and used Gorilla Glue around the vertical perimeter (*not* under the edge) as both a joint filler (because it expands), and an adhesive. After it dried, some sanding to shape the excess it into a fillet, and then I taped the corner with lightweight glass.

I did it this way because I wanted to make the sole able to be fairly easily and non-destructively removed at some time in the future, as the fuel tank is under there, along with easy access to the engine back-end/reduction gear and also tiller, if ever needed. I think it could be removed with a razor knife, and easily so with an oscillating tool, but between the glue and the tape, is not in any danger of coming out on its own

Also, during all this I noted that the tiller shaft tube terminates just a couple inches above the waterline, so I cut and trimmed a piece of PVC pipe to raise that up 7-8", to just under the cockpit sole. I glued this in with Gorilla Glue so it can be easily removed if/when ever needed. Now there is a much lesser chance of shipping water around the shaft in waves or with stern squat., and that tube can be cut away in a minute or so.

This did raise the sole a bit over an inch, but I arranged the glass so that it tapers down and outward, and tapered the coring a bit so that it has a slight slant forward. The forward edge of the cockpit sole on an A-30 is where the drains are, and I left the new core about 4" short of the forward wall, so that area is like a 'sump' for trapping small amounts of water which would otherwise stand.

To finish, I cut down the tiller base bracket by 1" so that the tiller head would fit on there as normal, and made a boot of Sunbrella which is tucked under the base and comes up over the first 6" or so of tiller, to prevent or at the least slow any leakage around the shaft there getting belowdecks.

Hope some of that helps!