Chesapeake 17 bulkhead fit


My Chesapeake 17 is now elevated over the sawhorses and seems to be true and untwisted.  I dry fit the bulkheads, taking care to insure they are in the correcyt locations and discovered that in both cases there are noticeable gaps between the bottom point of hte bulkheads and the v in sole.  In the case of the aft bulkhead the gap is alnost 1 inch and tapers off towards the side.  The forward bulkhead only has a  1/4 in gap.  I expect that when I wire the bulkheads and tighten it up the gaps will be noticeably reduced but this will change the shape of the bottom somewhat.  Alternatively, I can trim the sides but this will drop the notch in the top corners of the bulkhead below the top of the sheer clamps - by how much I'm  not sure but I expect by a noticeable amount.  I guess the final solution is to leave it and fill it when I fillet the panels.  Thoughts?

Separately, I will have to leave the boat for a couple of weeks, preferably elevated as it is now.  Is this ok or do I need to worry about deforming the hull if left suspended for   a long period?  Thanks much


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RE: Chesapeake 17 bulkhead fit



i have build several of the Chesapeake 17s....the one inch gap sounds a bit large. the 1/4 inch gap is not abnormal.

can you confirm if you are building from a kit or cutting your own pieces from a pattern?   it may help us understand the possible issues at play.

i would also encourage you to take a picture and post it with your would be really useful to the folks trying to help you.  if you don't know how, its easy and well worth the little bit of work to lear to do that.  in the course of my building and getting help, taking a quick picture and posting it with my question really improved the quality of the responses i got.   so on this 1 inch gap....don't really know what to say without understanding your situation better.

on leaving the boat for an extended period.  should not be a problem.  that said, it is best when you leave it to ensure it is basically in the shape you want it (no twists or obvious alignment problems).  this way, to the extent the wood takes on its current shape as it 'natural' will not have to fight against it to get it in the right shape.



RE: Chesapeake 17 bulkhead fit

   Thanks.  The boat s being built from a kit.  I will try to post a picture when I get back to the boat which may not be for a week or two.

RE: Chesapeake 17 bulkhead fit

   I built two Chesapeakes from kit and had similar fit problems with 3 of the 4 bulkheads.  After my boats were built, I saw John Harris post here that he finds the bulkheads fit better if you remove the spreader stick.  I did not know that trick so I trimmed them up to get the best average fit I could, then filled the gaps with filets.  I suggest that you make sure that the bulkhead is high enough so that it will support the deck when added.  A big fillet on the bottom of the bulkhead is easy because you will do that with the deck off.  Filling a big gap between the BH and deck will be a pain because the deck is in place and you have to work through the hatch openings.  If needed, you can add little blocks of scap Okoume to help hold the bulkhead exactly where you want it.  I glued a couple in place with CA glue then ran big filets over top of them.  Whatever you do, do not tighten the BH wires so much that it deforms the hull.  You want the hull to be fair and smooth.  Hope that this helps. 

RE: Chesapeake 17 bulkhead fit

I experienced fit problems with temporary bulkheads as well.  Kept spreading the seam apart as I tightened wires.  Resolved it by cutting the stitches out and rewiring, taking great care to only tighten enough to bring seam together, On the backmostform i actually resorted to cutting off the tip of it, about 1" back.  This prevented the tip from pushing the seam apart.   

RE: Chesapeake 17 bulkhead fit

Following the advice/request resulting from my original post I have posted a photo of my forward bulkhead fit.  The space at the bottom is aboiuut 1/2 in.  I have a similar situation with the aft bulkhead - I'm not sure how to attach 2 photos to the post but suffice it say for now that with the aft bulkhead I have about an inch from the bottom of the bulkhead tot he vee in the sole.  The fit in both cases is very snug on the sides and I expect to trim the sides a bit but I assume I need to avoid dropping the point where the bulkhead fits into the shear clamp by much. I also assume that I shouldnt rely on using the wires to pull the bulkhead closer to the sole since that would presumably deform the hull.   Other than doing a bit of everything and addressing the spaces with fillets is there something else I should be doing?  Please don't feel obligated to repeat what you may have already written - I appreciate the input.   I am posting again because I now have the photo so any knew thoughts would be helpful.  Thanks.  Bruce   

RE: Chesapeake 17 bulkhead fit

Thanks for the picture.

can you confirm your picture in your post is of the front (closest to the bow) bulkhead. fwiw...just eyeballing it it looks like a rear bulkhead.  i have built several of the 17s over the years and the kit build boats usually fit pretty close if everything is lined up something interesting is going on here.

if there is any doubt, a picture of each bulkhead plus its measurement at their widest and tallest points would allow CLC to confirm you have the right parts.  also double check and record the measurement of the bulkhead locations from the front of the boat...should at least allow another set of eyes to confirm the basic measurements are close to where they are supposed to be.

attached is the video series of building the CLC 17....#4...and if you look at it you will see a front bulkhead....and a rear bulkhead.

like i said, your picture, to me,  doesn't look like the front bulkhead.

in the only see minor gaps.

the other comment i would make since you haven't glued the boat together yet is that it is much more comfortable and less painful and a bit lighter if you round off the lower inside corner of the sheer clamps with a 3/8 to 1/2 inch router.  this way you won't bang your knees into a sharp corner.   it can still be done but you would probably have to re-stitch the sides as its hard to do on the panel without it being on the floor or on a solid table.

let us know what you see.  apologies if its all just camera distortion....but double checking the parts can't hurt.

thanks for posting the picture. 


RE: Chesapeake 17 bulkhead fit

   So itt looks like I had mislabeled the bulkhead - sorry about that.  The new picture I have posted shows both bulkheads, looking towards the bow.  In addition, I discovered that the forward bulkhead was 2" too forward and that has been corrected in the photo here.  The effect of that seems to have incresed the space at the bottom to about 3/4 in.  There is play in the forward bulkhead which would drop the piece somewhat lower with the reult that the notches at the ends will fall below the shear clamps. The aft bulkhead is propoerly located but, as I indicated earlier, very tight.  I'm sure I can shave the sides to drop it some but that will also create space at the shear clamps.

I am pretty sure these are the right bulkheads for the Chesapeake 17 but, just in case not, here are the dimensions:

width:  forward - 18 5/8

            aft        - 22

Height Forward - 11 5/8

           aft             10 9/16


As to rounding the sheer clamps, i found that suggestion on the forum after I got to this point but I don't have a router anyway.  I was thinking I might be able to round the lower edge with a Stanley sureform and a sanding block.  I know that might be tedious but, in the absence of a router are there any other suggestions?  Thanks again.  Bruce 

RE: Chesapeake 17 bulkhead fit


first i wanted to share with you a good site

that may be helpful.

in looking at your latest picture i would suggest the following:

1) push the bulkheads down so that the outside lower corners of the bulkhead are lined up with the lower edge of the sides of the boat.

2) move the bulkhead a little fore or aft to so that the lower edges of the bulkead (the sides that mate with the bottom pieces of the hull)  equal the length of the lower edges.

these two moves should eliminate the gaps with the bulkhead and get the hull in the right shape.

because the parts are CNC cut, they should be right want the hull to follow the shape of the bulkhead.  lining it up with the top of the shear clamps is not the correct alignment point.  you will plane that into alignment when you plane the tops of the shears with the form.

if the bulkheads are a little off from the fore-aft expected measurement, you are ok.  the key thing is to ensure that the rear bulkhead is not significantly ahead of its expected location, if it is a bit further back, that is fine.  and the same for the forward bulkhead, as long as its adjusted location is not significantly shortening the cockpit.  

also confirm that your wides point of the boat is 24" at the right location - 112 inches from the bow.

try that and let us know how it looks.

in terms of rounding off the bottom of the shear clamps, if i didn't have a router i would use a block plane to round it off.  i think that would be the fastest...followed up with sanding.



RE: Chesapeake 17 bulkhead fit

Interesting.......I have only two bulkheads in my 17. One just ahead of the cockpit and one just aft of the cockpit. The foward deck at the puzzle joint is supported by a deck beam.  I'm thinking that these bulkheads are in the wrong place. See the CLC deck installation video on U-Tube.  But some are referencing four bulkheads. Things change I guess.   

My bulkheads defined the hull shape. So the bottom joints sucked up to the deck made more sense than alignment at the shear clamps. Which could be fixed with a sister framed bulkhead piece if necessary before the deck is installed.    

RE: Chesapeake 17 bulkhead fit

Essentiallly I agree with "hspira".  I   retrieved the manual from the shop. Comparing it with your picture I see, your foward bulkhead appears to match my forward bulkhead in shape with a 16" radius deck line. Is it at station 64" from the bow. 

The aft one appears to be an aft bulkhead with the 24" radius deck line. Is it at station 124" from the datum?   

Maybe it is perspective but there appears way too much aft deck on this boat behind the cockpit area based upon hull shape and percieved distance.  I'd check the locations of the bulkheads to the plans and trust the CNC machine for bulkhead size.

see Cheasapeake Light Craft ,  Assembly Manual for the Cheasapeak 17, etc, 10/2010, V3.1, page 172


ps....those sharp shear clamps are anoying on the knees......If all else fails knee brace like pads will work once you establish where the knees will be.

RE: Chesapeake 17 bulkhead fit

just to confirm what Sun said, the chesapeake has only two bulkheads.  it also has two deck beams.

i suspect the reference to 4 bulkheads above was just a mistake.  there are other designs, like the shearwater that come with 4 bulkheads (two permanent and two temporary) but not the Chesapeake.




RE: Chesapeake 17 bulkhead fit

   Sorry to obsess about this but I am trying to get it reasonably correct before I move on.  As my first boat - and first venture into a project of any kind like this - I am trying to learn as much as possible with the minimum number of mistakes.  This photo reflects the adjustments following hspira's suggestions.  (BTW, the Geiger site is terrific - thanks) Locations of the builkheads and the max beam have all been double checked and verified. The bulkheads have been pushed down as much as possible with the following result.  The forward bulkhead now has only about 1/4 inch of space at the bottom and some space along the sides.  I could probably get a better fit if I trimmed slightly one or both of the upper sides of the bulkhead but I'm not sure that is desirable.  The aft bulkhead now fits flush on the sides and the space at the bottom  has been reduced to about 1/2 in, though forcing the bulkhead down has created some spaces at the nearby hull/bottom seam that will have to be addressed.  The spaces along the sides and bottom of the bulkheads are considerable greater than shown in the CLC video and maybe I need to do some trimming but they don't seem out of line with what, based on the some responses I have read, others seem to have experienced.  So do I keep fussing with this or is it time to move on?

More importantly, I discovered that the bottom halves of the aft bulkhead are not symmetrical.  One side has a noticeably shalllower angle from the center bottom to the side radius than the other.  At first I thought it might be an optical illusion but I measured and indeed they are different.  To be precise, the distance from the top of the bulkhead to the bottom, keeping the same distance from the bulkhead edge, is 3/8" longer on one side than the other.  It doesnt seem like much but, at a minimum, unless its addressed, it means the bottom halves cannot be drawn tight to the bottom of the bulkhead and still produce a symmetrical bottom. Any thoughts on this?  Thanks

RE: Chesapeake 17 bulkhead fit

looks like you are getting close.  

-  move the bulkhead a little fore or aft to so that the lower edges of the bulkead (the sides that mate with the bottom pieces of the hull)  equal the width of the bottom hull halfs that it sits on top of.

at the end of the day, the position of the bulkheads should not distort the hull.  depending on your assembly there can be a little variation in terms of where the bulkhead sits..   the reference to where the front of the boat is for measuring bulkhead locations can have a little noise.  if the bottom edges of the bulkhead are not matched with the width of the bottom hull piece it is up against,  (e.g., the bulkhead bottom edges are longer than the width of the bottom sections of the hull) it will create a 'bulge' in the hull.  for the aft bulk-head try moving it forward a bit and see what that looks like.

let us know the the measurement of where they sit when you make that (hopefully) little adjustment.

as for the assymetry.....that's odd.  i would check in the CLC and see what they say.


RE: Chesapeake 17 bulkhead fit

   Also, when you invert the boat to adjust, tighten, wedge, and fair the panels, gravity will help push those bottom panels to the bulkheads, if their widths match. Then use a long skinny stick (8' X 1/2" X 3/4" works) to see what the bottom is doing. If there are hard spots at the bulkheads, tighten or loosen the stitches or move the bulkhead or trim the bulkhead. "Fair" beats "correct" every time. 

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