This is from a recent Ches 17LT builder.   I have seen many references to the same problem, and experienced it myself (poor fit of deck underside to top of b/heads).   Unless the gap is tiny (say 1/4" or less, in which case you can fill it with thickened epoxy), you'd do better by cutting a curved, narrow (to suit the width of the gap, plus say 1/2") strip of 3 or 4mm ply and epoxying this vertically on the face of the b/head, pushed upwards to a close fit under the deck, so as to close the gap.   You can probably hold this piece in-place with strong tape while the epoxy cures.

Not quite sure that I understand point 2 - sorry!  

I installed a CLC Happy Bottom seat in my Ches 17 and later Shearwater 17 - excellent item!

(You may want to think about the necessity - or otherwise - of glassing the decks, unless the craft is going to be highly stressed such as in surf, big waves, etc.   If just day-to-day recreational paddling, simply roller-on a thinned coat of epoxy, sand after curing, and varnish over the top of that).

Wordsmith

I had the same bulkhead issue also.  Ditto on Wordsmith's answer.

I was very unhappy with the back band.  I grabbed the closed cell foam piece I used on top of my car for resting my yak on and used that for back support.  Perfect.  Been using it for 3 yrs. Just glued it in place.

Kim

I haven't built my 17 yet but have read the book & manual and thought through nearly every process... this one has also crossed my mind. 

It seems to me that using band-straps around a deck that overhangs the sides puts lateral pressure on the deck, pushing the top up and away from the beams/bulkheads.  Unfortunately, you're not looking at these, you're looking at that nice tight seal along the edges and thinking... Kewl!

My solution will be to clamp the deck in the center of the deck beam (and bulkhead at the rear), then use heavy sand bags or equivalent along the top center toward each end, and nailing the edges without the aid of the straps.  Of course, I'll enlist the aid of my wife (which she'll love) to help with all the holding it'll no doubt take.

Anyway, my 2¢, FWIW... and I agree with the poster, this place is a goldmine of information!

L

Discovering a gap between the underside of the deck panel and the bulkheads is common.  Use some thickened epoxy and put a nice fillet to seal the area.  The vertical stern seam should be filled with thickened epoxy and shaped during the initial sanding - before glassing.  I installed rapid pulse in both my Ch16's - very comfortable.

 http://www.flickr.com/photos/algonquinpaddler/356410145/in/set-1784126/ 

I've had the same problem with the bulkhead as the other people who've responded.  I just used thickened epoxy to fill the gap.  Worked out pretty good, got it nice and smooth by going over it with a brush.

 As for the seat, I didn't like the foam and backband, just wasn't very comfortable to me.  I looked around to see what kind of seats were available online.  Didn't have much luck there.  While I was at a local kayak shop, I asked them if they could special order a seat for any of the kayaks they sold.  They responded by saying not really but they'd had a couple seats from two kayaks they'd had to destroy for some reason.  So I got a Wilderness Systems seat for $35.00.  Definately a huge improvement and very comfortable.  There's some pictures of it on my build page.

http://www.flickr.com/photos/12642403@N05/page3/

Seat was an almost perfect fit and now is perfect since I put some extra foam underneath it to stop it from the slight bit of sliding around it did.

Eric

I'm in mid-build and I have a large gap between my deck and both bulkheads, despite a sheer clamp that seemed to have been planed perfectly.  I plan to cut out "fingernail" shaped pieces of 4mm scrap and epoxy those into the gaps, holding them in there somehow, maybe with copper stitches, maybe with hope, maybe with some weird clamping rig between the cockpit and hatch, while the glue dries.  Possibly I'll take an easier path and just make larger pieces and glue them to the faces of the bulkheads, but I think the "fingernails" approach is less clunky.

Regarding question #2, if I recall, I used fiberglass tape on both bow and stern, if that's what you call "finishing".

I've been wondering about the seat question too, especially since finally climbing into my kayak yesterday and realizing how compact the space is.  I really want to have something comfortable, and will probably go hardcore extravagant with the Creature Comfort seat.