Core Sound 20 Hull #102

[Charlie Jones]

well, kinda sorta ;D Yeah - basically, the top 6 feet is the taper, give or take a few inches. It's not a critical thing that has to be EXACTLY 6 feet, so don't obsess if it comes out 6 feet 3 inches or something.

Oh- and I bore the top down about 6 inches and glue in a dowel- probably a one inch one for the 20'r masts.

And I bet it isn't your last question ;D I've been building boats and messing around rebuilding boats since 1976- and I still call Graham now and again to check something.

[Norman Colter]

Wes,

  The Princess masts taper from the six foot mark. Main mast diameter 4 3/4 inches for six feet then tapering to 2 1/4 Inches

  Mizzen 3 1/2 inches for six feet then tapering to 2 1/4 inches.

  Nice sheet from Graham, "Cat ketch spar plan" shows birdsmouth dimensions, Sprits, several halyard options and a sail stop. Plus all needed info for pivot location, snotter attachment, etc. Maybe you're missing a sheet?

  Good luck, have fun 

Norm

[Charlie Jones]

Can't do that with aluminum lower halves though. So the taper started ABOVE the lower aluminum piece. The lower half was aluminum, the upper was birdsmouth.

On the 17 I used two pieces of aluminum, one fitted into the other and a tapered wooden top third.

On the 20 it's different yet- more like the Princess, just different sizes.

[wkisting]

Yes, yes... I meant "last question FOR NOW"    You guys are a tough crowd of critics. Seriously though, thanks very much for all the help. I wouldn't even have known I was missing several of the plan sheets if not for comments and posts here. Poor Carla has to keep mailing the missing sheets to me, but she's been a very good sport about it.

Just so you don't worry that I really did run out of questions....

Where should I order sail track from? I'm planning to order my sails from Graham, but does he also supply sail track, or where is a good (cost-effective) place to buy it? And what kind?

IIRC, someone mentioned that he wished he had made the masts longer than called for in the plans (I forget why... maybe to accommodate a top halyard block or something like that? I can't find those comments in the forum archive, but I know I saw them somewhere). What is the ideal length for CS20 masts if I'm planning to use sail track to attach the sail? Do I need to add any length, or just build them to plan?

Started gluing up the pieces for the centerboard last night. Also cut out and glued up the rudder pieces about two weeks ago, but haven't actually assembled it yet. I'm planning to glass the rudder blade first before I cut the spacer blocks for the rudder cheeks so that I can get the clearance correct. How much glass should I put on the rudder blade and CB?

[Peter HK]

How much glass should I put on the rudder blade and CB?

It's just for abrasion resistance, not structural.

I used 6oz.

Peter HK

[Doug Cameron]

Looking at my rudder and centerboard from the Everglades Challenge, I would say the most abrasion resistance is needed on the bottom edge and the lower 4-5 inches of the leading edge.  On the sides you just need resistance to the rubbing on the cheeks and the trunk as it goes up and down.

I echo Ray -- there are many good reasons, including price, to buy from Graham.

[wkisting]

Hmmm... unfortunately, I can't yet envision how to rig the CS20, so I'm not able to order everything at once. I hope Graham won't mind getting asked to ship something every other week. 

Right now, I need rudder pintles/gudgeons and sail track, as I will want both of those while building each of those pieces. Anything else you recommend I order up front instead of later?

Here's the centerboard I put together yesterday and the rudder (and cheeks) I made a couple of weeks ago.

[wkisting]

Thanks Ray... actually I'm a long way from decking, but I'm thinking about masts already because I'll need them to make the mast tubes when I get to that step. Just planning ahead so the work doesn't pile up, and so I have something to do while the cockpit seats are getting installed and curing.

I'm confused... my CS20 plans have two separate sheets showing the masts: "Rigging & Sail Plan" and "Cat Ketch Spar Plan".

The problem is that the first sheet clearly shows the Mizzen sail with a 17'7" luff plus 3' 8" of clearance of the bottom of the spar (i.e., at least 21' 4" tall), and the Main sail with a luff 19'3" plus 2'2" of clearance on the bottom of the spar (i.e.., at least 21' 5" tall). However, the OTHER sheet says that the TOTAL height of the Mizzen mast is 18' 11" and of the Main mast is 19' 8 3/4". That's a big discrepancy. Which is correct? The second sheet is more recent, having been updated in 06, but it's strange to have such a large conflict, and I'm afraid of building my masts too short.

Help!

[Designer]

I am sorry for the confusion but there are two rigs on the CS20, sleeve luff and sail track with roach and battens.

The sleeve luff has no roach because you can't roll a normally battened sail around the mast and therefore the masts are taller to make up for the lost sail area.

I encourage the sail track version on the CS20 because I think that it is safer and more efficient.

You can see how well the sails set on Dawn Patrol when reefed. Alan told me that "the boat handled and balanced well just like under full sail in less wind".

[wkisting]

Thanks Graham... When you get a chance, I'll be interested to know what the cost would be on a "complete rigging kit" for the CS20, including rudder and centerboard hardware and all the blocks, eyestraps, etc. to set up the CS20 with sails on tracks (and anything else you consider part of the "ideal" rigging setup).

Oh, to the rest of the forum folks: I talked with Graham on the phone today and he was just as friendly and helpful as everyone says. Don't take my many questions on this thread as a reflection on the quality of Graham's plan sheets... I'm working with a slightly older set and by some fluke, it is missing a few sheets (Carla has kindly sent me replacements). But even with the missing sheets, I'm having FAR fewer troubles than I've had with other sets of boat plans. And the boat is looking great! I installed the side bulkheads and bottom stringers today.

[Charlie Jones]

On Graham's prices- I have a wholesale account with a marine distributor, as a licensed boat builder.

A full set of hardware for the last boat I built , a 20,  cost me pretty much the same as what I'd have paid from the wholesaler. Some difference of course- they have to make a bit on it too or they couldn't do it. But considering that I called Carla and said "send me ALL the hardware for the 20" and got a box full, all labeled, including the running rigging, all measured and labeled, and a bit of extra line, it is well worth the few bucks they make.

Plus it saved me HUGE amounts of time and effort.

They understand what you need, have it on hand and sell it at a reasonable cost- how can you go wrong?

[Garry]

And it is good quality stuff.

[wkisting]

Came across another discrepancy in the plans... the cutout sheet shows that the vertical portion of the front mast step is cut out of the same sheet as the forward hull panels (which, of course, is 1/4"). So that's what I did. However, today I noticed that elsewhere the plans spec that it should be made of 3/8" plywood. Problem is, I already cut and installed the 1/4" ply. Will it be strong enough if I cap it with 3/8", or do I need to "beef up" the vertical portion with reinforcement?

What do you think?

[Designer]

Thanks for pointing that out Wes, I have already corrected the plans. I think that 1/4" ply is adequate for that web as there is very little compression loading with a free standing mast. I made it 3/8" ply because the weight difference is so small and I like to make the critical components as fail safe as I can. You could add a bit more glass around the step and it will be fine.

It is always hard to predict what cruel and unusual punishment we will inflict on these parts. While sailing from Sanibel to Cape Romano and well offshore at around 3:00 AM, the boat was close reaching with a good sea running doing around 8-10 when Southern Skimmer suddenly stopped. The running backstay was loose and snarled a crab pot float on the lee side. Fortunately nothing broke but there must have been some good shock loads on the rig.

[wkisting]

Got the forward mast step installed, filleted, and taped in place. Came out very nicely, though my dimensions don't fully match the plans (it's a bit larger than spec'd, but very stiff and solid, so should work fine).

So here's a dilemma you've probably all heard before... I was planning to get a 2 hp motor to put on the transom, but I see that all the 4-strokes weigh in the 41 lbs. range (except the air-cooled Honda, which I hear is noisy). So I already own a 2-stroke 8hp Johnson that I really like. I was thinking it was too large for the CS20, but it's only 58 lbs. (not much heavier, but a LOT more powerful, than the 2hp 4-strokes). Maybe I should consider building a motor well for it inside the aft deck area? Or hanging it off the transom?

Of course, I'll probably use an electric trolling motor most of the time (for getting away from the dock, etc.), but on the ocean, I'd be a bit apprehensive not having a motor for backup in heavy winds/currents. Just curious to hear everyone's thoughts...

[wkisting]

Thanks Ray, maybe I'll sell the 8 hp after all. Should be a fairly hot item... 2005 with only 40 hours of use on it and METICULOUSLY broken in because the only week we used it was on our honeymoon. I had nothing else to do while manning the helm, so I followed the break in procedures to the letter and varied the throttle setting every 5 minutes, never revving above half-throttle until it had the requisite 10-20 hours on it. Then I varied the throttle from 3/4 - full for the next 10 hours. It's a spotless motor, and after the 2006 regulations, about the nicest, newest 2-stroke 8hp that can be found other than those still sitting in boxes somewhere.

If you know anyone in the GA area who is interested or willing to come pick it up, I'm probably going to list it on eBay or Craigslist for $1100 in the next few weeks. (MSRP was something like $1600-1800, though I didn't pay quite that much for it.... I guess because of the 2-strokes being phased out, I've seen these selling as high as $2400, which strikes me as a crazy price to pay.)

By the way... do you recommend an anchor locker on the CS20? Or just keep the rode in a bucket in the cockpit?

[jaxsailr]

Hello Wes,

I have a Honda 2 long shaft, while it can be noisy at higher throttle setting it serves me very well and no water pump to worry about.  I lucked out and found it on Craigs list in like new condition.  The nice thing is it has a centrifugal clutch which makes starting and docking easier on the nerves.  Here in Jacksonville theres always a current to deal with in the river and the inter-costal.  I do have a Johnson 3.3 and it runs well, but has no neutral.  Since I have not used it much I can't report on the noise level.

Fair Leads,

Niels

[wkisting]

Well, I've already got my mast step installed and it's too deep to use as the floor of the anchor locker, so I'll have to install a second, higher floor, which is fine... it'll just make the bow stronger (not that it needs any more reinforcement).

Do you cut any kind of access door to get at the rope, or just a pipe through the top deck? I've never used the pipes with the removable caps, but are they large enough to reach in through? I thought they are usually about 2" wide, oval shaped--just large enough to accommodate rope and chain? Do you have a picture?

[wkisting]

Do you just make the anchor locker drain forward through a hole in the bow, or how else do you keep it dry in there with a wet rode?

Also, Ray, where did you get the Canberra wood shown in your thread about skinning a cat (http://www.messing-about.com/forums/index.php?topic=5420.45)? Is that Canberra also that you used for the thwarts/rowing seats? Looks like Mahogany at the thwarts, but I'd like to imitate your colors since we're also planning a white hull with bright deck.

[wkisting]

Thanks Ray!

About the CS20 seats... Are the butt blocks shown in the plans required, or are they a substitute for scarfing? (Are they needed to provide structural rigidity, or merely to join the top seat panels together?) If scarfing will suffice, I would prefer that to the butt blocks.

I'm also considering adding more horizontal stringers of 3/4" x 1" Fir running athwartships under each seat to provide extra support/rigidity to the seat tops. Is this unnecessary? I'm concerned about larger passengers (250+) stepping up or down onto 1/4" plywood as the seats are designed.