CS17 #226

[Apteryx]

Last night looking through the build notes, I didn't see any direction as to whether the step between the thick bottom and the thinner forward bottom section should be inside, or outside.

I think I like the idea of the stringers, which I'm guessing cross the forward scarf joint.  They would be much easier to fit to the  fair side of the bottom.  On the other hand, there would need to be quite a bit of filler to fair out the step on the outside of the hull.  Maybe a foot wide swath?

Which way do most folks go?

Thanks for all the advice, as a first-time builder I really appreciate it.

[Ken_Potts]

I built with the step on the inside.  I think I remember it being the recommended way but I'm not looking at my plans right now so I can't be sure.

I didn't make any great effort to hide the scarf on the inside of the boat and it's not something I see when I look at the boat (I see lots of ugly stuff on my boat but that step is either under the forward seat or under the floorboards I put in so it's just not obvious).  I think when Ray puts the scarf on the outside he's building on a jig.  He's trying to speed the building process in order to make a living (correct me if I'm wrong there, Ray).  If I (as an impatient amateur) were to put the step on the outside I think it would be more of a challenge than I'm interested in to get the outside of the hull fair.

I built from plans, not a kit so your results will vary (are you building a kit?).  If the edges of the step-scarfed panels match up when the step is on the inside (which I suspect they do) that's the way to go.

[Apteryx]

The unfair side could be either inside or outside, it just depends on which half you use on which side.  Up until Ray's tip about eliminating the stringers, I'd always envisioned it smooth side out.

With deference to Ray's skill and experience, I think that's probably the way I will do it, because I don't trust myself to get a fair curve with filler.  On the inside I think I'll fill it so there won't be an edge to chafe or chip.

Which brings up another question - two layers of fiberglass on the outside of the hull, I think, is considered good practice.  Inside, I've heard I should put maybe three coats of epoxy and paint, but skip the fiberglass.  Does that sound right?

Many thanks for all the good advice here!

[John Burritt]

If you don't glass the outside of the hull, you'll need to tape and fair the outside of all the seams.  Glass the outside, you don't need the tape.  One layer of glass should be more than sufficient to strengthen all the seams and toughen up the hull.  Not sure what weight cloth Graham is recommending.  Do both, and you still have the problem of fairing so the tape doesn't telegraph thru.

[Apteryx]

I've heard good things about the sails Graham provides, however, I sail with a group including a nicely respected sailmaker.  Politics of the matter aside I've seen his work, and his sails always seem to fit perfectly and fill to such perfect shapes.  He's also got experience with traditional rigs such as gaff-headed sails and balanced lugs.  I don't know that he's ever built a sail for a sprit boom, but I'm pretty sure he's done sprit sails.

He's likely to be more expensive than Graham, in fact I'm sure of it, but for my personal little rocketship it's worth it.

I haven't seen any suggested measurements.  If anyone has some I'd appreciate hearing from you, particularly with regard to the stays'l.

[Apteryx]

I don't see from the plans how the transom fits - does it fit inside the hull and topsides pieces, or on the ends of them?

Also, and I may be missing the obvious, are there any cleats around the edges to bond to the transom?  Seems like there should be.

While I'm yapping away with endless questions, I'm thinking about adding some pieces under the seat tops, maybe one every two feet.  For want of a better term, trusses to carry loads to the edges where the load will transfer to the seat stringer or the seat face.  Sound reasonable, or is that a waste of weight above the waterline?

I'm building the aft deck version of the CS17, and have been considering a shelf on each side so there's a bit more organization to the stowage.  Any thoughts on that?

Many thanks in advance - this place is a wonderful resource!

[Designer]

Carl,

The transom fits inside the sides and bottom.

No, there is no transom frame. The joint will be filleted and taped on the inside and rounded over on the outside and glassed.

[PAR]

Damn, you're supposed to fillet and tape that joint, oops . . . will nails do? ;D

[PeterP]

I put in extra 3/4 x 1 1/2 beams in the seat tops. My fear was that sooner or later I would step off a dock carrying a cooler or what not and crack the ply in the seat.  Hard to fix that. You could spoil your whole day doing something like that. Also the little cubbies are a terrific idea. I had precisely the same idea myself a while back and in fact I ended up tearing out the back of a perfectly good boat so I could put two of them in. Look at the pictures. It will hold my GPS & VHF( when I remember to bring it). It will hold my thermos of tea (which never gets forgotten). All right there. Perfect. PeterP

[Apteryx]

Dang, that's a nice looking boat - I hope mine looks just as nice when she grows up!  ;D

Thanks for your comments.  I had this grand scheme of getting my boat 3-D this past long weekend but details, details, and my plodding pace got in the way.  Ain't no thing, though.  I glue a seat stringer, I stand back and think, wow, what a cool seat stringer.  Someday I hope to stand back and say, wow, did I really build that boat myself?

But in the meantime, a step at a time, having fun with each step, that's the ticket.  In fact, the idea of building a boat seems rather academic.  Tonight I fair up some filled holes, and maybe get the other seat stringer ready.  Makes me feel like I'm following the right path, reward in itself.

[Hirilonde]

Dang, that's a nice looking boat - I hope mine looks just as nice when she grows up!  ;D

You should see it in person.  I had that opportunity a couple months ago.  As a matter of fact, the top picture looks like she is next to Graham's dock, possibly that very week end.  You should ask him for close ups of his mock stem and tiller.  Peter had way too much fun building that boat.

[Ken_Potts]

Peter had way too much fun sailing that boat too!  He was out in the thick of it when the rest of us were standing on the dock  ;D  I think Dawn's still traumatized from seeing the bottom of that boat while Peter was heading out 

[PeterP]

Thank you for the kind words - yes the boat picture at the dock is from the get together. Kindly provided by Paul Steward. And yes it was a blast sailing it that day. It was also a great fun meeting you all and I still say Let's Do It Again. Only Carla needs to come up with better weather. Don't know what got into her that day. PeterP

[Apteryx]

Someday I'll be around to worrying about masts, and I've been kicking around the idea of birds mouth versus aluminum.  I suspect the wood is lighter, but I'm not sure.  I plan to make one-piece masts regardless of materials.

Lee makes router bits for cutting the grooves and it sounds practical to make a perfect (hah!) octogonal cross section.  That would yield nice surfaces for mounting a mast track, cleats, etc.

Any thoughts, birds mouth wood versus aluminum spar?  I am no fan of varnishing, but I'll do what I gotta do. 

[PAR]

After a couple of discussions with Graham, aluminum is the best performance option. Wooden, birdsmouth will be overly flexible with typical wood species and wall thicknesses used. Using a denser wood and/or increasing the stave thickness will produce a stiffer section, but at the cost of weight aloft, which is a "no-no" in an unstayed rig.

A good compromise between performance and affordability, would be a 10' aluminum lower section with a birdsmouth top.

I've found special router bits a waste of money. I first started birdsmouth mast building many years ago, before most called it such. I used a table saw, a good datto blade and two well positioned feather boards to keep "chatter" to a minimum on small staves. I've been using a router table and a V shaped fence for several years now, and it's a much easier method to control. Interestingly enough the fence was made on the table saw with the same datto blade.

Don't be tempted to buy 22.5 degree router bits. You'll lose about 50% of the gluing surface within the joint. Also, the asymmetrical stave layout will save you time and slightly increase the gluing surface, within the joint, plus make rounding easier.

[Roger Peterson]

"I've been using a router table and a V shaped fence for several years now, and it's a much easier method to control."

Hi Par,

Could you show us a picture of your V-shaped fence? I have already completed my mast but would like to see your fence so I can build a birdsmouth mast for my next project.

[PAR]

The sketch should be self explanatory. A symmetrical stave cut is shown which is the preferred way. I misspoke earlier and said an asymmetrical was the better choice. The symmetric layout has an offset notch, but leaves the outside of the mast an octagon. An asymmetric layout has an evenly divided notch, but the outside of the mast will be fluted, which is harder to sand round. The nice thing about this arrangement is you can use your fingers to bear on the stave, as it runs through the router, without fear the bit will get you.[attachment=1]

[Hirilonde]

If both the table saw and router will do the job I virtually always choose the table saw. It is not for fear of using a router.  I have repaired the masts for several Concordias, including a 1939 31 ft. sloop using a router to reef out the glue joints for a spline.  In spite of the risks, some times it is the only viable choice.

It is usually safer to use a table saw. It is often more accurate to use a table saw, or maybe I should say, less likely to result in a slip and thus ruin the work.  Like Ray, I seldom, hmm, ok, never use dado blades, and for the same reason.  The set up time is prohibitive.  The only time I can see using one is on large production type jobs where the set up time is compensated for.  I never seem to get large production jobs, so this never happens.

I guess it all boils down to what makes you feel comfortable and confident in what you are doing.  Creativity is measured by the result.

[Charlie Jones]

I use the table saw also and also with the standard blade- quick and simple. With Laura assisting a bit I cut the staves for both masts on the last CS 20 in about 30 minutes, including ripping the staves, but not including setup time for the birdsmouth cuts. Probably an hour all together. I do heartily agree with PAR- the offset cut with the narrow part out makes an easier rounding. But you can also control the thickness of the stave a bit by changing where that centers. Put more meat inside or outside as needed.

When I built the masts for the Princess 22 I weighed the aluminum lowers and the wooden upper halves separately- the wooden uppers were lighter than the lowers by a few pounds- not enough to get excited about really, but lighter.

[Apteryx]

Thanks for all the comments!  I imagine a birdsmouth upper and aluminum tubing lower will be the way to go.  It won't look as classy as all wood masts but I don't want to give up performance to excessive mast flex.

Using guides sure opens up a lot of possibilities with a tool like a router or a table saw.  That 45 degree guide block is something to remember.  That sketch took time to make - very gracious of you, PAR.

Interesting, too, how much the dado blade slows you speedy-cats down.  I spend too much time trying to figure out my next move.  Dado setup doesn't seem to be a big deal by comparison.  When I did my last scarf sled I used a dado blade to help fix the guide slat to run in the table groove, and to set the fence piece accurately.  It took three or four test cuts to get the dado shimmed precisely, but when everything in the shop takes forever I don't think I really noticed the extra time.

I'm available for hire, by the way.  I work by the hour.... 

I've had zero confidence in anything free-hand, but last night I tapered my first seat stringer.  Amazing.  I think I took 20 minutes with a jack plane, cutting down to a pencil line, and the taper is only barely short of machine precision.  A metal straightedge appears to fit precisely.  Looking closely, there is some variation but the surface undulations are probably no more than a few thousandth's of an inch.  I'm cool with that!

A couple of passes with a random orbital sander and the jack plane's tool marks disappeared.  For those of us in the remedial woodworking classes, this sort of thing is most rewarding!  ;D