C-Forum

So I put new rails on my spark. When the hull was bare, i made marks on either side and took measurements. This was last fall. Couple days ago, hull still bare, all those measurements were up to one and three eighths inches different. What could have happened?
Sun shining, had the day off, so i put the new gunwales on and as expected,bending the new gunwales around the hull deformed it. Im now ready to use the thwarts to conform the hull back to its proper shape, but im not trusting those marks. I especially dont want to mess up the shape of the bow.
If anyone with a spark could throw a tape on the bow and get some dimensions, id be much obliged.
Say the width, inside of royalite to inside of royalite, at 10 inches, 20,30,40,50.
Thanks so much to anyone who can help!

I measure the lengths of the thwarts, from inside the royalite to inside the royalite, from my 2013 red Spark. From the bow to the stern, starting and finishing with the thwart-like grab-handles, the lengths are:
1. 220-mm
2. 450-mm
3. 630-mm
4. 530-mm
5. 410-mm
6. 135-mm

I always mention to people to push the boat out wider behind center, so there's not so much tumblehome.

Kaz,

How much wider? 50-mm (2 inches)?

Thank you so much!
I ended up taking the gunwales back off and getting some measurements of the hull naked...but i haventmade any further progress on the thwarts because i dislocated my friggen shoulder coming up from a roll...just popped out...
Ill use those dimensions to cut the thwarts and will crank the stern wider. Thanks again..

No worries, matt1.

My boat is standard, but in terms of how much to widen the boat (I might do it down the track), I found the following info from a couple of old threads:

What I did to my Spark is remove the rear wood deck, take out the last 2 rear thwarts and push the hull out as much as you comfortably can, then cut new thwarts to fit the wider hull. You can re-use one of the thwarts you pull out. If you do this, it will make a boat a little bit drier(in theory). Also, the little wood deck won't fit back on. JKaz

I pushed the stern of mine out two inches at the rear thwart. I took all the thwarts out and pushed the stern out two inches then made all the other thwarts "fit" the new contour. The bow thwart had to be lengthened slightly as well and I did not move the saddle. I had to make a new stern deck plate as the old one would no longer fit. The boat was much drier and did not get swamped with following water nearly as bad as when it was stock. I thought it got even easier to roll as well. I did not notice any significant changes in hull speed. Cheajack

Pea Pod, that's exactly right. And Chea jack. Good job!

Every self-respecting boater should have a thwart stretcher.