mustangermatt

My 17 is being built decked. Besides the good looks we needed the storage for our planned camping trips. Originally I had thought that the aft deck would prevent people from crowding aft and causing the transom to drag, but my wife and I are already eying the aft deck as a great place to loaf in a light breeze

Ok, I was able to make a decision on my boat. I have to keep coming back to my "mission statement" which is simplicity. To that end I originally decided against an outboard, and I am going to stick with that. However I am going to glue a heavy doubler to the inside of the transom so if I change my mind in a year I won't have to hang upside down in the lazerette trying figure out a way to bolt a bracket on. An engineless sailboat becalmed is a better excuse than running out of gas any day, just ask my wife

Very good point. I was also thinking that if the balance is wrong I can change a lot by moving the pin. I also read about a guy who races IC's with his board raked forward, and wins consistently. You are right, nothing is permanent

I am making a couple of changes in the centerboard area on my Coresound 17. First after an email conversation with Graham I have moved the trunk aft 3 1/2". I am using slightly different sails than the design (snipe cause they are cheap used and plentiful :-) which pushes the balance aft a little. We had originally discussed "a couple of inches" but when I rechecked my calculations I realized I had not taken into account the roach on these sails. Also the board foil changes below will move the center of lift on the board forward. The second change will be the cross section of the centerboard. On the plans it is basically a flat board with nice fairing fore and aft. I researched board shape and came up with thethickness should be 8% - 12% of the chord length for a slow moving foil (most sail boats). This will provide more lift and a higher angle of attack before stall. So my board will be 1.4" thick, almost 1/2" thicker than the plan. I found a table of offsets for NACA foils that I am using to get the cross section. The board will be foam core glass with a Poplar stiffener (1.2" x 3.5") at the widest part of the foil to take the side force of the board against the trunk. The head of the board will be as drawn in the plan. I will also use the same NACA foil scaled down for the rudder and similar construction. I figured it was ok to experiment with the rudder and board foils since they are easily replaced if I screw up. The one I worry about is the trunk placement since that is permanent, but I am pretty confident that I calculated it as close as can be on paper. :shock:

I have not decided if I am going to have any provision for an outboard. Originally I planned on strictly sail and oars. The one reason I would do anything for an outboard is because it is easier now than later. If I do it will be something along the lines of the well, but I will have to work out the shaft length. Don't some of the other coresounds without the aft deck just hang the outboard right off the transom? The well should be the same height I think.

I have seen a very small "well" used on blanchard jr's, which are 19' and have a covered aft deck. The well is no more than a recess in the aft deck just ahead of the transom. It is about 4" deep, 6" wide and maybe 4" or 5" long, with one or two drain holes through the transom overboard. This gives an area on the transom for the outboard to clamp to without breaching the water tight integrity of the after comparment. The main thing is that the well is big enough to unscrew the motor clamps. The transom usually has some reinforcing in this area. On the blanchards the well is usually in the center of the transom as the rudder is under the boat, not behind it. I don't see any reason you couldn't put the well to one side. Now that I think of it I might do something like this on mine :-)

It is hard to tell in a photo but it looks like the joint was done with glass cloth instead of tape. I was just reading a post from someone who did that to keep the joint from failing while unfolding the boat. My guess is if it made it through unfolding, and then manhandling and a trailer ride without being properly stiched, don't touch a thing! It's a good joint :-) Is there anymore history on the boat? It seems like a really curious point for somebody to quit.

Thanks, that is good encouragment. Isn't your boat on the Weekender builders page? I came close to ordering the Weekender plans with the idea of building it open like your boat before I discovered the Coresound. The cat ketch sold me on the Coresound :-) Suprise is a very pretty boat.

You are not alone in this problem. The assembly design is very clever and makes for a real nice bow, but there are a number of ways to have "unexpected" results. I actually used four layers of 5.6 oz.tape on both sides of each joint since I wanted to carry the flat area a couple of inches aft of the designed joint (14" of flat). Thus the bow joint held fine but the next joint back started to tear where the 1/4" bottom ply meets the 3/8" bottom. This was quite easy to fix by taking 10" 1x2, laying it on the outside of the curve on the damaged joint, then screwing drywall screws through the ply into this batten. Once I had flattened the joint back out I added more layers of tape and epoxy, next morning it was good as new. I really think you should to try this first as the vertical area in the bow adds alot to the unique looks of the coresound, and will also keep the pounding down in a chop. If you look back in some of the posts you will find variations on this theme for others who have had similar "incidents". Good luck and let us know how it turns out.

I had two problems to solve with the seat tops. First was the 3 ply fir is less rigid across the grain than the 5 ply counterparts. Second is teenage girls and a 10 year old son jumping from god knows where into the boat, Graham had suggested turning the wood 90 degrees and doing more butt joints. I experimented quite a bit and came up with the framing in the photos. I decided on this rather than Grahams approach mostly because of the incoming teenage projectiles. I actually only added three frames per side, for a total of less than five pounds of wood. One of the frames forward is the rail that supports the centerboard trunk carried out to the stringer, and I added another full width frame between it and the forward bulkhead. All the joints are notched to interlock, glued, and the ones along the stringers are screwed. Now for that centerboard trunk... [attachment over 4 years old deleted by admin]

How are you doing the seams with glue? Are you gluing to a chine log or something?

The plans specify 9-10 oz tape, but I have been using 5.5 0z and doubling the layers. I was able to run the bow joint flat back 14 inches without a break. Some guys using the 10 oz have reported cracks at this joint if they try to go past 10 inches. Where this relates to your post is that it is alot easier to fair in the lighter tape, doing it in layers. My scarf joints look like varnished wood. It does cost a bit more though since the price difference between the tapes is nominal and I am using twice as much.

I just finished the sides on mine, the are filleted and taped both sides of the bottom front and rear edges. The marine fir I am using is 3 ply instead of 5 ply for the 1/4' thickness. This means that it flexes more across the grain than okuome. Graham suggested turning the wood 90 degrees and adding a butt joint for the seat tops. What I wound up doing after much experimentation was adding additional frames to keep the run of unsupported wood below 15 inches. This framework is both screwed and glued to the stringers. It makes a very rigid top that should hold up well to my kids jumping around. I am using a taped rounded seam at the seam at the jont between the seat top seat side and a fillet and taped seam at the jont between the seat top and boat side. I use drywall screws to hold the ply to the frames while the glue dries. I will try to post some pictures tonight.

I am 5' 6", so I have to climb in no matter where I put the boat :-)

Congrats on the plans. I think you'll really be pleased. I am going with a painted hull because epoxy is so sensitive to UV. I am glassing the entire exterior (four kids climbing around you know). The photos Graham posted of the bright transom sure looked good though. I am just building the seats in my CS 17 now, I have to take the boat a family reunion in the San Juan islands July 4 just to prove something to an obnoxious brother inlaw :-) Looks like I will make it with some time to spare. One thing I would change in the way I built mine is the building cradle. Mine holds the boat about 6 inches off the floor and working under the boat is a pain. Also I spend alot of time bending over the boat. Something like 2 1/2 feet would be nicer.

Brad, I think you missed my point :-)

I happened to see some portable lights in Walmart the other day. They looked somewhat like a large flash light that cliped into a mount. They used several D cells. Since I like to sleep at night the only time these would be used is if I get where I am going later than planed (likely on a boat without an engine :-) This is in keeping with the whole objective of my project, which is simplicity. No engine, no electronics, no electrical system.

Here is an unstayed mast wood mast that seems to be doing the trick :-) Its a traditional dutch fishing vessel called a Botter. I had the pleasure of caring for and sailing on one as a Sea Scout for several years when I was a teenager. They are much faster than they look ;-) [attachment over 4 years old deleted by admin]

I have got to hand it to you guys building nesting dingys. After spending the last 7 months building the hull for our coresound 17 I am having trouble getting the courage up just to cut the centerboard hole, much less cut the whole boat in half :-)

A quote from Boatbuilding Manual by Robert M. Stewart who had over 60 years in the boatbuilding industry as a builder and designer with major firms prior to his death in 1996: "Yellow Pine (Longleaf) Weight about 3.4 lbs. (heavy). Strong, very durable, and straight grained. Used for stringers, clamps, and for planking if weight is not a factor, also as a substitute for white oak keels, deadwood, etc. May be available in long lengths in some localities. Has been reported as not durable in fresh water, but I cannot substantiate this. Grows in southern United States in Atlantic and Gulf states." I am using Doug Fir since that is what is plentiful here in the Northwest, but I would have used Yellow Pine in a heartbeat for the keel skeg and keel batten if I could have found it around here :-)

I don't know about the okoume but with domestic fir ply the variation in thickness is due to finish sanding. I saw one sheet of 1/4" fir that had been sanded all the way through in one place. I guess the guy running the sander dozed off or something :-) I am lucky to live within driving distance of a supplier so I can inspect each sheet before I buy it.

Thanks , that was exactly what I needed

I have cs 17 #97's hull assembled and faired with the stringers in. I am reviewing the seat framing on the plans now and I noticed that there are alot of parts screwed rather than glued. My very limited experience with the epoxy has been that the wood will split or break before the joint itself fails. With the screwed joint the fastener usually pulls out of the wood first (but not always). So is there an overwhelming reason not to continue with the epoxy joints for the interior construction and framing? Thanks Matt

I feel for you Graham. The software company I work for uses both windows and Linux. Two months ago I finally "Microsoft patched" my windows machine out of commission. I had to do a complete reinstall of the OS. The Linux box goes four to six months without a reboot, much less "patches". Oh, and the linux OS is free ;-)

Ah, silly me. Maybe it's time to get my glasses checked. Thanks