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Core Sound 15 kit


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Hey Dale, 

 

The heel is a bit excessive in the photo I agree but she is going to windward in a breeze with full sail so in that moment perhaps a little overpowered with just me and I think I like that about the picture. I do think thought that flatter is not always faster especially in the Core Sound hull shape. You got me thinking though so I took the model of the 15 and put it to some heel angles to see the effect on wetted surface area. The numbers seem to indicate that at 15 degrees of heel a pretty nice reduction of about 20 percent is achieved. So in the picture the boat is probably heeled about 30 degrees which corresponds to a 29% surface area reduction. Who knows if she would have been faster if she had been flatter in those conditions, probably so and foils (boards and sails) start to really drop off as heel (and thus spanwise-flow) increases much past 25 degrees in a sailboat i believe. But what i'm getting at is that there are SO many factors you certainly can't just say that flat is always fastest. In very light wind for example heeling the boat helps with sail shape as gravity works in your favor "drooping" the sails into shape. Heeling to windward in very light air is very very slow. Similarly i'll sometimes heel the boat downwind to keep the sail from "falling" back into the center of the boat from gravity in very light conditions. In a breeze your likely hiking out and so 10-15 degrees of heel is pretty normal just because you don't want to heel into the wind suddenly while hiking if you get a leeward shift in the breeze. In our Core Sound 20 Dawn Patrol we find that she does really well at about 20 degrees of heel. Heel also make is a LOT easier to sail through chop which we can have a lot of on Core Sound.  I think this is a combination of the effective waterline beam being reduced and the chine acting somewhat like a deep-v keel does on an offshore powerboat. Anyway, that's been my experience for what it's worth. I'll be curious to discuss with Graham as well. 

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Hey y'all, I'm really intrigued about the CS-15 Mk-3 as a solo cruiser. I like Alans rendering. A couple of thoughts, at least the way I would want it.

 

  1. Raise the sheer, and leave the cabin height as it is on the rendering. That would let it look less "chunky".

  2. Drop the berth height and eliminate the footwell. Sit up with feet up cross-legged. Kinda like being in a tent. I'm a solo sailor.

  3. Have a forward hatch instead of sliders and full length tunnel. 

  4. Outboard on transom and no oars. Use space in backrest/coamings for stowage with access through bins through coamings instead of oars.

  5. Definitely keep the water ballast.

 

How about it Alan---willing to give it a try?

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The photo of Alan in the CS15 is now my desktop. He was probably sailing at that angle because it is fun. This is why I switched from sailing cats to monos. I do miss the speed of cats but I love sailing a mono on the edge of capsize regardless of efficiency, which is why I mostly sail alone and no longer get invited on friends boats. Which suits me fine.

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Alan, I love the scientific approach. I often take my current sailboat out and record VMG to figure out what works best as sometimes "feel" gets in the way of reality. I think it's one of the reasons racing is a great way to learn about trim and boat speed, because the other boats become temporary "constants" to tweak to. 

 

I also wanted to commend you on your instructional videos. I know how much goes into producing these as I do a fair amount for my job. They are a great reference for those about to build. When I built my Spindrift 11N, I just took my time and thought a lot, probably doubling the time it should have took me to build. I guess the building thing is addicting. I am heading to look at Doug's CS20.3 this Friday, just because I feel if I am going to spend a few hundred hours building a boat I should look at it first. I'm fairly positive, as Carla already has my CC!. 

 

Take Care,

Steve

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I like my new word span wise flow. I just have not figured out how I am going to use it.

 

I also like the graphic hull emersion vs angle of heal. I printed it out so I could hang it up in the boat shop. I think visitors would find it interesting, but I feel a little guilty for lifting it from Alan. I would feel better if there was a little donation box so if I like watching your video or I want to copy one of your graphics I could drop something in the kitty.

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One other consideration on heel vs. efficiency is that as speed rises (presumably accompanied by increased heel) wave-making becomes the dominant factor in resistance vs. that of wetted surface area. The heeled hull shape becomes an important factor in the ultimate speed achieved.

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Alan,

Thanks for  the technical explanation.  I still like the idea of less healing than in the photo.  I am not big on technical stuff though.  I like to just get out and sail.

 

I totally agree with the idea that that you deserve something for all you videos and charts that we love so much.  My local Independent Radio station has a icon they call the tip jar and you can click on it to contribute anytime.  Maybe you could come up with something like that.  I guess it would have to be on your website.

dale

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Hey guys, Thanks for the support.

 

I would like to announce the addition of a "tip jar" to my blog http://www.sailnaway.blogspot.com/ to help take the edge off of video production. I had thought of making a donate button on the blog for a long time. Feel free to donate at will!

 

I am working on a number of projects at the moment that keep me from cranking out these CS-15 videos but rest assured I will get them done. I'm working on #19 even now.

 

There is seemingly (and in fact) no end to the work when it comes to boats I have found. Some of the projects i'm currently involved in include but are NOT limited to...

 

-Helping finish the big 45' power catamaran at B&B

-Finishing up a Spindrift 12 for our neighbors at B&B

-Upgrading the CNC machine at B&B to a water cooled spindle with vacuum hold down table

-Updating and adding more information and pages to the B&B website

-Putting a few last touches on the Kit files for the CS-15 kit. 

-Helping to finish the Assembly Manual for the CS-17Mk3 with lots of rendered 3d views from Rhino. like the one pictured below.

-Updating my dad's Core Sound 20 Dawn Patrol to have a weighted centerboard for another run in this years Everglades Challenge.

-Restoring an old Centerboard from a Thistle.  

 

 

Here is one of the renderings of the cockpit module from the Assembly Manual for the CS-17Mk3 that I've been helping with. Hope Graham gets his 17Mk3 done soon so we can go test her out!

9_module_baffles.jpg

 

-Alan

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Love it!  I think these videos will sell the boats like hot cakes.

 

I haven't been able to get my 17 to go windward like that (yet) but I realize that is more due to skipper skill than boat lacking.

 

Has anyone installed hiking straps on one of these boats?  I have found myself sticking a toe under the thwart too.  A little slip could put some quick separation between skipper and boat.  :o

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Alan sure makes it look easy. But I don't want to do that hiking stuff at my age---and definitely not with hooking my toes under a thwart!!!  But if ya gotta hike, hiking straps sound like a great idea! Actually, these boats can make ANY of us look better than we really are. Must be that genius designer!

 

Watching this video was great fun, but I WANNA GO SAILING !

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  • 2 months later...

Finally uploaded another CS 15 build video. This time glassing the hull. I didn't get video of most of the actual wetting out however. I think I remember it was pretty hot in the shop and I couldn't handle pumping, mixing, applying and cameraman duties all at once. I've updated all the files for the CS 15 kit based on things learned in the prototype and we have started cutting one out for a customer this past weekend. The 15 from the videos was picked up last month and is now in Florida. 

 

 

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Great job. I do pretty much the same but I'll ad a few comments.
  1. I do the entire transom as a separate piece overlapping onto the sides and bottom. This gives a double layer on the joints. I like to finish my transoms bright and this eliminates an overlap in the center that may show up in the clear finish.
  2. I pre-lay a strip of glass around the centerboard trunk that wraps over the edge and down into the trunk to cover the edge of the bottom ply. When I build the trunk, I sand a bit of flair into the bottom edge to allow room for this layer that laps into the inside.
  3. For those that don't have a router to inset the flange of the bailer, just mount it without the inset. The drag from the flange as you are sailing won't be that big of a deal---unless you want it perfect so you can whip Alan in the races...
  4. On larger boats that one width of glass won't cover the side and bottom together, or if you are concerned about being able to wet-out that large of an area at one time, do the side and bottom with separate pieces overlapping the chine. Because of the time it takes that allows the resin to kick-off before you can finish a section, you could let each section cure before doing the next section. If you do, feather the edge of the first piece before adding the next or you may have a void that will trap air along the overlap.

 

Can't wait for the video about final sanding and paint. That is my biggest area needing improvement. I'm always looking for short cuts, or wanting to skimp on materials, and it always shows! Maybe only God can help with this. My prayer is; "Dear God, give me patience....and give it to me NOW!"

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