Core Sound 15 -- The Decision and Some General Questions

[Guest Dennis M]

My son and I unfolded the boat and things went well until one of the tapes on the panel broke. My question is, does one need to "retape" the panel, or can one continue to stitch the bow? I'm thinking that I am going to have to retape because of the way the bow panel at the chine does not hold its shape. Any one here have their 2 cents to put in?

Thanks, Dennis

[wkisting]

My vote would be to retape, else you risk not having a fair (symmetrical) shape at the bow. May seem like more work to retape now, but I'd bet that it will save you work later compared to proceeding without retaping. The quality of the early stitching process is crucial to producing a fair hull.

[Ken_Potts]

  I broke that joint on one side of my CS17.  I fixed it by pulling it flat with blocks on the inside and outside and retaping (without unfolding the hull).  I can see a difference between the broken side and the unbroken side.  I don't know how many other people see it but I do.

  If you want the boat to be as pretty as possible you should consider pulling the stitches and retaping the panels while flat.

[Guest Dennis M]

Wes and Ken, thanks for the reply. I have sanded all back to bare wood and reapplied the tapes. Graham suggested I attach 2" square blocks of 3/8 ply to the aft inside of the seam. I'm hoping to stitch it up tomorrow and see if I cannot get it unfolded without mishap.

I do have a question: The last time I had it unfolded, the seem on the fwd lower bow section would cup up into the other side. Trying to force that panel down so that the edges mated was virtually impossible. Anyone else have this happen? Any tricks of the trade you can share? I'd appreciate it very much. Regards, Dennis

[Designer]

Dennis,

You should not be having trouble bringing the paneld together at the chine.

Do your panels look like the picture when you join the bottom to the side at the bow? The chines should run along side each other for a couple of feet.

[Guest Dennis M]

Hi, Graham,

My butterfly looks exactly like the pic. I have no trouble with the chine where the topsides meet the bottom. The difficulty lies where the bottom seams join right where the bow section begins to curve up. Once opened, the one panel rides up into the other and trying to get that panel down (or the other one up) so that the ply edges meet is where I am having the difficulty. I apologize for not being able to draw an appropriate word pic, but that is as good as I can do at the moment. ~Dennis

[Designer]

Okay, I got your problem. If you refer to the cutout sheet you will see a note about rounding over the inside corner of the center seam.

There is a lot of compression on the inside center seam especially at the forefoot and with two sharp corners, one side will ride over the other side. With the inside corners rounded over you have two blunt edges bearing against each other so there is less tendency for one side to ride up over it's partner and if it does it is easier to force the errant side back into place.

[Guest Dennis M]

Graham, thanks so much. I did see that note and for some reason thought it applied to the ply edge from just where the forefoot begins to curve up. I rounded off the section aft of that, but not the forefoot proper. Sheesh! Dumb mistake on my part.

[Guest Dennis M]

OK, I finally got the boat unfolded without mishap! I've stitched up the panels, inserted the temporary center frame. All has looked good to this point except. . .

1. My plywood is either growing or shrinking. The bottom panel is either far too long or the side panels are far too short. When I match up the transom to the sides and bottom, there is a significant amount of bottom panel that will need to be sawed off once I get everything set. I'm scratching my head at this point because I measured meticulously, or so I thought, and several times. In trying to get a handle on the situation, I took a measurement from the bow to the aft side of the transom centerline (top) and find I'm two inches at least long! What the heck! I'm gonna have my tape measure exorcised!

So, now I'm second guessing all my measurements, including the lines drawn for frame placement and the like. Graham, can you tell me how far the temporary center frame mold is from the bow down the c/l and to the tops of the frames where they meet the side panel. I'd like to try to get a good measure of that at least. I can get those measurements for the fwd bulkhead off the plans, but the temp mold measurements are only on the panel layout sheet. Thanks, Dennis

[Guest Dennis M]

Progress is being made! I have the boat stitched up and the frames in. The bottom panel stitches have been tightened. There were some gaps (3) in the seam that needed something other than copper wire to coax together. So, I stuck some 3/4" x #6 stainless screws in the bottom panel and used a clamp to draw the panels together. This worked very well and held things shipshape until I could get a couple more wire ties in to hold things together. When I removed the clamp and screws -- voila! -- things held nicely. There are about 3 gaps in the bottom panel that I could not draw together and are not much more that 1/8" across. Putty and tape will take care of them just fine. These, I suspect, reflect my less than steady hand on the saw when cutting out the panels.

When I unfolded the boat on my first try, the seams broke at the tape. Graham suggested 2x2 3/8 inch ply blocks screwed into the panels on the aft end of the butterfly seam. I used 1/4 ply held in by  3 3/4 #6 stainless steel screws and things unfolded like magic, and without any sound of cracking at the tapes.

Now that I have it stitched up, the boat has really taken a nice shape. So far, everything looks according to plan. I began to put the inwales in last night, but the joint on my scarf failed, putting an end to that first attempt. It was the first scarf joint I ever made, so I am not surprised. However, when I had fiddled around with the thing the previous night and had it set in place, it went in easy as pie. I am not sure why it would bend OK on night and not the next.

A couple of things to note:

1) The excess on the bilge panel that I mentioned previously was not due to a mismeasurement on my part or the result of a magical growth of dead ply. For those building the CS15, the bottom panel will be about 3/4" longer at midships and somewhat less at the sides. I ran a pen along the transom bottom and established a cutting line and trimmed the excess off.

2) At the bow, I note that one of the side panels is approx 1/8" (if that) higher than the other side panel at the bow. I'm not sure how that happened unless I was not quite as careful on alignment of the butterfly as I should have been.

A couple of questions:

1. Butterfly Tapes -- are these to be sanded off or cut at the seam when the filleting and taping the boat?

2. As I am no woodworker, and would appreciate someone giving me some instructions as to how to get the bow sections of the inwale beveled to fit nicely there.

Thanks,

Dennis

[Designer]

Dennis,

Here is the paragraph on fitting the inwales that I am writing on for the CS kit.

The inwales meet at a compound bevel at the bow.  This is a difficult cut, to have the pieces mate nicely.  Make an approximate cut on each piece.  Then clamp them in place, letting the aft ends run past the stern.  Now use a hand saw to cut between the two pieces.  Tap on the aft ends of the inwales to drive the joint together.  This can be done as many times as necessary to get a good fit.  (While large gaps can be filled with thickened epoxy, it is so easy to get a good fit that it is worth the short time it takes.)You can run the hand saw between the side panels while cutting the inwales. Just be careful when driving the inwales forward, if you get heavy handed you can blow the whole thing apart.

Where you have gaps caused by bumps from cutting, you can easily fill the gaps with epoxy. Before you epoxy I would check the fairness around the gaps. I have found hollows at the gaps and have wedged them further apart to make the hull fair. I have also removed ties from around a bump and run a jigsaw through the seam to ease the bump. A little effort will help create a sweet looking hull.

[Guest Dennis M]

Thanks, Graham. Such tricks and hints are helpful. ~ Dennis

[Guest Dennis M]

All, I got the bevel on the inwale successfully cut this p.m. For newbies to wood working, I have some further things to add to Graham's instruction above which may be of use to some one.

How does one get an approximate bevel for the inwale? This was the line in Graham's instructions that puzzled me. So, I took some scrap and practiced on it first. What did I discover? Well:

1. The ties at the bow (the top 2 or so depending on how you stitched it up) need to be loose enough initially to allow the inwale to extend past the plywood edge of the bow.

2. Width wise, scribe a line on the inwale following edge of the ply at the bow.

3. Cut that line and you have an inwale edge that follows the bow line where the ply edges meet. 1-3 are pretty clear cut.

4. To get the rough compound bevel. I ran the fwd end of the inwales past the ply edges just a tad. Took a straight edge (a block), cited down the c/l of the boat, lined up the block as near as I could to that  line on the top of the inwale along plywood edge of the bow, drew a line, and then cut on that line. This gave me a nearly perfect bevel requiring only 3 passes with the handsaw to give me a nice fit. I tapped the inwales with a rubber mallet and gently is the word, here to be sure. I had to replace ties a couple of times -- not because I blew things out when hammering in the inwale, but because in my practice runs I weakened one tie with a saw tooth a time or two. There is a lot of force up forward once the inwales are in place, so be careful.

It is easy as pie, but it would be helpful to have an extra pair of hands when you go to tighten the ties and draw things together. Afterwards, I drilled a hole and drove a 1 X#8 ss screw to hold thing in place.

I apologize to anyone who sees this as being so obvious, but very raw practitioners of the art of woodworking, like myself, often need a tad bit more to go on. ~ Dennis

[Ken_Potts]

  Good work Dennis!  I'm looking forward to seeing your boat come to life.

  Please don't apologize for being "so obvious" because there are a lot of newcomers who read this forum and can learn from your work.  There are also a lot of old hands who are occasionally surprised by a novel way of accomplishing a task.

  In the meantime - Can you post a more detailed picture of the waterfowl carving that accompanies your signature?  I've been looking at the tiny thumbnail for a while now wishing I could see it for real 

[Guest Dennis M]

Hi, Ken, the waterfowl carving is a mother pelican feeding her young her life's blood. In classical antiquity, it was believed that pelicans, during famine, would rend their breast and feed their young and thus sacrifice its life for the fledglings. This symbol was adopted by Christians as sign of Jesus' own sacrifice for sinners. It is not a popular symbol today, but it was a prominent one at one time and artistic representations in stain glass. If you Google "Pie Pelicane" or Good Pelican, or Pelican in her piety, and you will get a huge number of hits and photos. I can't remember where I got mine from, but here it is:

That did not do any good and I can't find the larger image from which I derived the pic. Sorry.

[dave chase]

Hi Dennis, 

Greetings from Holland, MI.  I just came across your original post regarding the Core Sound 15.  My wife and I have just gone through a similar decision process and are having a Jim Michalak 17' yawl  built beginning in October.  The CS 17 was high on our list, but decided that the Michalak cockpit fit us better.  We've sailed the Great Lakes and beyond on larger boats since 1970, but are looking forward to a simpler way to go.  Perhaps we should keep in touch.

Dave

[Guest Dennis M]

Hi, Dave,

I sail out on Lake Macatawa very regularly. I put in at Dunton Park and spend the day sailing the lake. I make out through the channel on occasion, but since I don't have a motor, the winds have to be just right for that to happen. I'd like to meet up with you sometime.

Cheers,

Dennis

PS: Tacked the seams of the boat tonight. I'm hoping that I can tape the seams this coming week-end before the cold weather hits.

[Guest Dennis M]

Good Evening, All,

Spent the last week filleting and taping the seams. I also got the keelson in today. I filleted and taped the centerline seam, although I know that somewhere Graham said that was unnecessary. Nevertheless, and despite the tediousness of filleting and taping (I'm glad I did not build a CS 17 or I'd still be at it), I think that taping the centerline seam prohibited me pulling a "dish" in the hull when screwing down the keelson. I put screws each side (1/2" from the edge) on 6" centers. This might have been overkill, but I've got the assurance that the thing in in place. After screwing the keelson down, I crawled under the hull to get a look at the fairness along the seam just in case I needed to ease up on a screw and was happy to see that all was in good shape. I will have a lot of filling and fairing when I turn the hull over, but that will be in the Spring.

I may have made an error in judgment, however. I filleted and taped the aft face of the fwd bulkhead (did this need to be done anyway?) before putting the keelson in. Now I have a gap between the keelson and bulkhead that will need to be filled in somehow, otherwise, it will become a catch-all for water and dirt. Other than that, things have gone well to this point.

We are going to be getting a week of warm weather, so I might be able to get the seat stringers, fwd mast step, king plank and deck stringers fitted.

I am taking pictures as I go, and when this roll of film is used up, I will post some pics. But that will be when the cold weather hits and I am no longer able to use glue for the season.

~Dennis

[Ken_Potts]

  Hi Dennis,

  It sounds like you're making good progress.  If I understand your situation you shouldn't worry about a small gap between the keelson and the forward bulkhead.  As long as you fill it so water runs the right direction you should be alright.

  Please continue to keep us posted and we'd love to see the pics when you've got the roll developed (don't feel too much peer pressure on that though - I think I'm probably notorious for failing to post pictures)  .

  Thanks for the explanation of the pelican carving.  Quite a story.  I've had many friends throughout the years who've been transformed by the arrival of a first child and it's nice to see that depicted in parable.

[Guest Dennis M]

Hello, All,

Got the center bulkheads fitted today. I ran out of tape so I won't glue them on until this week-end. When I fit the bulkheads, I made them a little tall to the mark on the side panel where the top of the stringer will fit. I then ran a 4 ft level across the boat (level to the top stringer mark on one of the side panels) to the other bulkhead , drew a line, and cut the tops of the bulkheads to that line. I'm hoping that this will make things nearly level when I fit the side stringers. I have one side of the boat slightly higher than the other, and so am using the slightly higher side as the standard for measuring. If I'm going about this the wrong way, I'd appreciate some correction before I glue the things in.

I also made the fwd mast step. Using a cardboard dummy, I held it to the outside of the hull roughly where the mast step is to rest, and scribed a line to get the curve of the bottom for the 3/8" ply web. It was too narrow on the inside of the hull to maneuver things neatly, and this gave me a near perfect fit to the inside of the hull. It probably would have been exact had I the hands of a surgeon when wielding a saw. Do I understand correctly that the top of the mast step (the wedge) does not rest against the hull? Is it only the web and mast tube that ultimately hold it in place? I was thinking that it perhaps should be scribed to fit the hull sides, but the plans don't give any indication that this is the case. Does anyone have a pic of the step prior to the tube being fit. If you do, I'd like a gander at it. Thanks, Dennis