I've never built one of those, but I did a SEARCH on this builders forum and put in the word SCARF and came up with this :   http://www.clcboats.com/forum/clcforum/thread/12648.html

It's a similar boat to the one your building and the author is asking about filleting the SCARFED side panels. Which I assume to mean the Chesapeake does not use PUZZLE joints but uses SCARFS for joining panels together.

I've built boats using both types of joints and it's a tossup b/t the two types of joints imho. Puzzle a bit easier and accurate for those of us who don't pay attention enough when joining joints together. Just an opinion. You might SEARCH using the word scarf and go through all the threads concerning scarf/joints etc.

If you look at the "What's included" under the Ches 18 order page the diagram shows scarf joints, or more accurately, it does not show puzzle joints. So unless they made an error on that page I would say they are scarf joints.

How about giving CLC a call and ask? I bet they know

David