Hi Andy, 

sounds like a tough day.   

i have built 4 chesapeake 17LTs over the years and i can appreciate the frustration.   i remember it becoming a complicated process becuase of the relationship between the deck pieces, cockpit, rear bulkhead and deckbeam at the forward end of the cockpit.

the good news is the 17LT is pretty accomodating of variation from the plans and after studying your drawings (plans vs what you did), i think you will be fine.

first, the most important elements are going to be the deck beam, deck pieces and the position of the rear bulkhead.   if these are not within a certain range, you end up with the deck not being able to cover the boat without cutting into rear bulkhead or the deckbeam.    this does not appear to be the case in your drawings.  the other good news is you deckbeam is pretty much where it should be.   and this is important becuase it establishes the forward most point where you can have the cockpit opening....and if that is in the correct place, your cockpit is going to be properly positioned.

so the real question i can see you focusing on here, is it looks like your rear bulkhead is 3 inches father back then the plans call for.   and i have some good news for you.  a lot of builders, myself included, push the rear bulkhead back a couple inches from the plans location to have some extra room to store things in the cockpit aft of the seat where it won't get in your way.  this can be a sponge, an extra water bottle, a camel hydration pack...etc.     

so in a nutshell, i think your proposal of 3 inch overhang vs 1 inch overhang is totally fine if that ensures the deck covers the boat and that the front of your coaming won't require you to cut into the deck beam.  And that is what i would do.

my only other suggestion is to continue to do what it sounds like you are doing which is dry fit the deckpieces to confirm the deck coverage after you have marked meeting point for the fore and aft deck. also, to the extent your deck coverage is more sensitive to the rear deck position (e.g., the deck piece with the least remaining overhang on the end, make sure to install the rear deck first)

a couple other minor comments.   1/4" in this kind of boat is well within the tolerances of variation that the finished product can have compared to the plans and still look and perform as designed.  second, the plan max width does not typically correlate to the widest part of a coaming in a kayak.   i won't get into the why that is....other than to say, it's not axiomatic that those max widths have the same location. 

i hope that was helpful.

h

H,

Thank you very much for your voice of experience.  I was hoping that a few added inches behind my back would be useful, so it's nice to hear that this should work out.  I will aim to keep the cockpit as close to the intended design as the materials allow.  I can't imagine what folks do if they build the boat exactly to the plans and end up without enough deck material!  

Thanks again,

Andy

   I also vote for building in a few spare inches into the back of the cockpit, for exactly the water bottle storage etc. stated reasons.  That is what I've purposefully done on two boats.  Yes, you will have a bit less bouyancy and a bit more water to get rid of if you capsize, but oh well.

Also, I worked to make sure my deck beam was (only) about 1 inch forward of the front of the cockpit opening.  I thought it might be nice to have room for fingers to have a nice grab surface under there when using the front of the cockpit edge to lift or pull.  Turns out to not be a big deal, but is nice and I'm not sure if it is better than having the front of the cockpit and deck beam exactly over one another, but with the 1 inch offset I don't think I've lost much at all structurally.  The back edge of the beam is under the front edge of the coaming pieces.  Would have to bash down on that coaming pretty hard to break anything right there.

   Hi folks,  I am running into similar difficultites with my 17LT.                       How well did the bulkheads fit at the gunwales? Here is a photo of my rear bulkhead at 4-1/2 inches aft of the 121-1/4" plan location.  It is a fair fit but I am concerned about the gaps with the gunwales.  The only way to get a tighter fit is to move the bulkhead even farther back.   

   Here is the photo.  The line is the plan position. Note the large gaps at the gunwales.  Thanks! Jay

   I figured it out. I had the distance across the beam too wide. 
when I corrected that the bulkheads fit much better. However, the rear bulkhead is still  about 3-1/2 inches aft of the plans.  

So at this point, its really your choice how you decide to go.  as mentioned above, the key reference point that you need to have correct is the forward deck beam.

from there, the question is do you want some additional space behind the rear seat (e.g., let the rear bulkhead float back a bit like you have) or not so much....in which case just move the bulkkhead forward a bit and see if you can pull the sides in a tad to close the gap or just use epoxy/wood glue paste to address any gap.

either way should be fine.

h