JeffM

I've finished my CS20's tank sides and have been looking at framing the seats. I don't see any framing in the plans, but I'm leery of plumping my 200+ lbs down on nothing by quarter-inch ply (grain transverse or not) with nothin' underneath. I've installed 1X2 framing for the 4 So-Pac hatches I plan to install -- maybe that'll be enough since they're at some of the widest parts of the seats, but I'm not sure. Ideas? Thanks, as always! I couldn't do this with any confidence withoug the support I get from you folks. Most Important Lesson of December: If you MUST epoxy, use a heater! It takes about 3 times more epoxy to cover a cold surface than a warm one -- and then it slooowwwwly runs all the hell over the place!

Charles, I'm building a CS20, and have also played around with hatch placement. I decided to go for So-Pac plastic hatches. I will install a large rectangular hatch in the aft bulkhead (fits nicely, with an opening big enough to get my head and shoulders into), and medium rectangular hatches into the seat tops of both aft and forward tanks. Though these hatches are not flush -- standing about half-an-inch above the seat surfaces and making "bumps" in my future bunks -- the seat sides were just not deep enough. Also, Graham has pointed out that any water in the bilge will tend to splash against the tank sides when heeling and get into any unsecured side openings. I'm still ruminating over the forepeak hatch: I can't see trying to access it through the foreward bulkhead -- given the cramped space between the foredeck and foreward seat top -- but I don't know whether to put yet a 4th So-Pac hatch up on the foredeck, or something else. Good luck! Jeff Michals-Brown

I've done a bit of reading on recent research into alternative propulsion. Seems the lowliest fish is WAY more efficient swimmer than the most sophisticated prop-driven boat. Seems that a lot of engine power is spent creating vortices (whirlpools) at prop edges that stir up the water and waste energy -- doing nothing to drive the boat forward. Part of the answer is blade area: the bigger the blade, the smaller (proportionately) the length of the edge. Hobie Cat's "Mirage Drive" takes advantage of this in their kayaks: two large blades pivot back and forth under the hull, twisting at each push of the pedals so that they drive the boat forward on every stroke. (Yes, kayakers pedal the things!) Put another way, it is more efficient to move more water slowly than to move a little water fast. For sheer power, Hobie Cat says that this propulsion beat another, two-man, paddled kayak in a tug of war. It is also about 10% more efficient than paddle propulsion (=going a bit farther at the same speed without getting more tired). I wonder how hard it would be to adapt a Byrnes hull to this drive? I expect a critical question would be the depth of trunk it could work in (A kayak doesn't draw much, so the pedals aren't far above the blades.) I wonder how fussy it would be to maintain in a salt water boat? If it were practical, I wonder if it would ever be worth the cost? (The drive alone sells for about $400.) And, of course, my Core Sound 20 is much more boat than a one-man kayak! The mirage drive is only one step along the way to something more radical: fish are far more efficient still -- something about creating vortices at one stroke, then recovering their energy by "pushing off" the same vortices on the return stroke... Back to the practical present: at the very least, it would seem that oars with big blades moved slowly are more efficent than smaller blades move more briskly. Ideas? Experiences?

Regarding Tom's initial comments: Would someone mind explaining to me why a long, shallow keel is not as good as a deep skinny one? I've thought of either adding chine strips to my Core Sound, or of installing the centerboard so that it protudes a couple inches even when retracted. (This to give me more control in very shallow water.) Jeff CS20 #65

Clean work, Tom! I'm at about the same point in my CS20. It looks from the framing as though you're making the stern a cross between decked and not decked: a raised seat to the transom. Did I get it right? Jeff CS20#65

Very pretty, Graham! I suppose putting ledges all the way around, while offering better support, would make it difficult or impossible to lift them up in the first place.

Thanks, Graham! That's exactly what I needed to know, and exactly why! -Jeff

CS Builders, I made a template to spec for the main mast step, dropped in into place where it fits well, measured back from the prow 22" to the location of the mast, dropped a plumbline and -- oops! The base of the mast lands right at the pointy end of the step. How big a problem is this? I could locate the step as is, but wonder whether the forces on the step would be better distributed over a larger step area (i.e. farther back, nearer the center of the triangle). When I try to position the step so the base of the mast is centered, it doesn't fit properly, and also runs into the foremost pair of bottom stringers. (On the plans, the step appears foreward of the stringers, whereas it fits better between the first and second pair.) I could make the step wider and notch it to fit over the stringers. That would mean forgetting the step specs, and going for more correct placement. Ideas?

Needing to install a second pair of seat stringers in my CS20 (mismeasured in the original installation), has given me an idea. Graham told me that the correct seat stringer height was important for getting the correct centerboard trunk height -- since the seat tops come out level with the top of the trunk. My idea is this: if I used my original stringers (or lowered the new ones), the cb trunk would indeed come out lower, and leave the leading edge of the board protruding from the bottom of the boat even when fully raised. Wouldn't this be a good thing in shallow water, since I would have some control of lateral plane even with the board all the way up? Also, I'd get more board for each inch I lowered it, owing to the longer triangle of board being exposed at any given depth. I know it's not that simple a mod, since lowering the stringers would change many other things well: the seats would be lower, the stepped portion of the mizzen mast shorter, the tanks smaller in volume, and so on. On the other hand, the board itself could be lowered by the simpler expedient of hinging it with a pin located higher up in the board, and altering that pokey bit at the top. Or I could just shut and trust that Graham had a reason for designing it the way he did, and build it to spec! Jeff

Thanks, all! A picture is beginning to form in my mind: 3/4 ledges on the seat side and part of the aft bulkhead. (A hatch prevents ledge from going all the way across.) Some sort of removeable fastener on the cb trunk. A floor of Graham's slatted design. (Any reason it can't be one piece? It can be lifted up at an angle to clear the ledges, but I suppose it would be heavy.) A cutout in the aft end center to allow access to the lazerette. Forward of the thwart same basic idea but in two pieces. The one for the cb side might even be left in place semi-permanently, since there isn't as much floor to loose there anyway.

Tom, Nice work. You're going like a house on fire! I've had my CS20 underway since mid-August, and I'm just ready to start on the interior. (Of course, it takes time correcting and papering over my errors.) I'm hoping to plan my work so the winter doesn't slow me up too much -- the boat's in an unheated garage. I'm putting the lazarette hatch in the aft bulkhead rather than the deck (a good, water-tight store-bought hatch -- easy but not cheap). I, also, thought about going into the forepeak through the foreward bulkhead, but with the seat there, and the deck extending so far aft of it, decided it would be too cramped and inaccessible. Instead, I'm thinking of putting in another store-bought hatch in the foredeck -- it lays nearly flush, avoiding the high box effect that interrupts the deck profile. The hatch opening is at least big enough to get my head, shoulder and one arm through without difficulty. (I'll enlist my boys for any work that requires more access.) I intend to chuck my anchor under the seat also, but figure I'm better off without an enclosed space around my wet anchor.

I want to answer this question in advance of beginning to install the bulkheads and seats in my CS20: What's the best way to make the seats into four bunks for camping? I've seen references to "raising the floorboards," but with no details. I picture a floor grate (teak?) raised level with the seattops in one of two ways: (1) resting them on a ledge of maybe 3/4X1-1/2 running along the fronts of the seats aft of the thwart, and on the seat-fronts and cb trunk forward of the thwart. (2) bolting the floorboards to the fronts of the seats with ss machine screws going into nuts epoxied to the insides of the seat frames (and cb trunk). Anybody out there ever done this? Other ideas? By the way, has anyone ever slept aboard their CS? How'd you do it?How'd it go? How stable and smooth was the "ride"? Jeff Michals-Brown, CS20#65

Charles, Graham has a picture of his Bay River Skiff (17ft) with a boom tent in his post of Fri, Jan 9 2004. I'm at work on a CS20. I also expect to camp in it with my 3 boys. It will sleep 4 without bumping heads, even though I'm 6'2". I expect eventually to fabricate something like Graham's tent, though I want screens to let in air and the view without the bugs. I'm about to start a separate thread to solicit ideas on how to raise the floorboards to make the seats into wide bunks.

How bout stowing your anchor there? Unless you deck-mount it, that would be better than putting a dripping anchor into the nice, clean forepeak.

Graham's 2X4 and ply oars are in his post of Mar 26 this year. The thread is "good source for oars." I've got it bookmarked until I get further. (Just taping outside seams now.)

Nice work, Joe. I'm over 200# myself, but I need footroom up there since I want to be able to sleep aboard (with family). The light deck beams worried me a bit, too. Also, I probably made a poor choice of wood: poplar. My answer was to make the beams a half-inch wider than called for. I couldn't see why not to, since there was wood enough when cutting them all nested from a 1X12.

Whoops! I did the same thing last week. Since the keel and keelson should make the bottom nearer the centerline really stiff, maybe I'll just add a stringers between the existing ones on each side. (I only hope the outer stringers won't interfere with the tank sides!)

Re: Graham's mention of difficulty of bending ply with exterior epoxied, that might explain why I broke so may wires and ended up needing one threaded rod to get the bow together, and another to get the bottom to conform its curve to the forward bulkhead. Took days to get most of the daylight out of the seams!

Foam in the luff sleeve is an interesting idea. But, assuming it's evenly distributed, wouldn't it give too little torque to be useful?

Beautiful, Ricardo! I am planning on leaving my transom bright also, but hadn't decided how to deal with the ugly edges of the ply sides and bottom. Yours is very finished and elegant. Jeff CS20 #65

Just about to start measuring bottom stringers for my CS20 (want to be ready to flip the hull over this weekend -- planning to rope in friends coming for a party). When I looked at the materials list to figure out what to cut them from, I discovered that bottom stringers were not there! What did you other CS20 builders do? I could rip a few of them from the remains of the board for my transom stiffener, but that wouldn't do the whole job. Is there any other slack in the lumber? Or do I need to get some nondescript wood from the local Lowes? I don't have a good source of finished lumber nearby -- my good stuff came from Maine Coast Lumber. Jeff

Hi, Bruce! I still look forward to sailing with you again. I don't think Graham specified a sail track in his plans; rather, he offers several options and leaves it to the builder. In what circumstances would you want the sails down in a hurry? Since there are no shrouds, you can let the sheets go even going straight downwind. Is the windage of completely flapping sails still great enough to be a danger? The ability to reef from the cockpit is an advantage with the sail track. But it seems a good option to sheet in the mizzen, leaving the boat to weathervane while I go forward, release the snotter, unlock and rotate the mast, and put the snotter back into the loop in the sail and in the reef grommet. If I recall, you also need to leave the tiller to reef, since you decided not to run the main halyard back to the cockpit in your own boat, preferring to forgo such reefing ability to reduce clutter and tangle. Jeff

Laced, track or sleeved? Let's see if I can summarize the pros and cons from the threads I've been able to find: A track-mounted sail luff is most flexible in terms of reefing (especially from the cockpit) and doing that neat trick of lowering the rig to lower the center of effort (hence heeling force) without reducing sail area. It's a bit more pricey and requires some extra work. It also takes longer to rig. A sleeve luff gives a nice clean airfoil, and is always on the mast and ready to go (reducing set-up time). But reefing it requires going up on the foredeck and rotating the mast while someone else holds the loose and madly-flapping clew. On the fly, it might be too much to manage on a rig as big as a CS20. If your boat is on a mooring, the furled sails would be waving around up in the sky instead of neatly tied to the sprit (?). No one seems to prefer lacing -- worst of both worlds? I like things fast and like the look of the sleeve luff. I wonder whether the rig-lowering trick could be managed by leaving the top of the sleeve open and rigging a halyard, then sliding the sleeve up or down the mast. (Too difficult with the friction of the whole sleeve against the mast?) I also wonder why, when the mast is rotated to reef or furl, it doesn't simply turn inside the sleeve? Getting ahead of myself, as usual (haven't even taped the outside of the hull yet), but just wondering...

Great adventure, Tim!

Paul, the clamps are nice, but I'm going to go with Scott's drywall screws: I'm afraid I'm both cheap AND lazy! Jeff