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Posted by Action Tiger on 08 May 2014 - 11:36 AM
Also, Richard, people DO build SOF sailboats. They also build sailboats from plastic bottles, and concrete.
Dave is right about a good sailboat. It makes sailing fun. So do good sails.
I have built some turds.
Don't break too many rules until you learn them fairly well.
That pointy triangle boat looks like a death trap. I'd want my buoyancy further forward.
Then again, what do I know? I never listen. Just ask my mom, or wife, or kids...
Posted by Designer on 19 March 2014 - 08:46 PM
I have just about finished making the first CS17 mk3 kit, I made the centerboard today. I am working on final tweaking and finishing up the plans and should have them available soon. There is a lot of detail and it takes time to get it all together.
I have been sneaking in a few duplicate parts so that I can have one.
Posted by Designer on 13 January 2014 - 09:40 PM
We waved farewell to Doug today as he drove off with his new Mk3. We were happy to get her out of the shop to get a good look at her rather than being too close all of the time. I feel that she more than met my expectations and you can still see the Core Sound heritage.
There is decent headroom, without the trunk cabin. It is very comfortable laying back against the hull, at 5' 7" sitting as tall as I could, my head was not touching the deck. I think that a 6 footer could find a comfortable position.
Posted by Designer on 04 October 2013 - 08:12 PM
Rather than hijack the mk2 thread I will start a new one.
Chick asked that I post some pictures of the mk3.
I started on a cabin version of the CS17 at least 5 years ago. I got involved in the big cat project and shelved it for a while. One night after work I was showing Alan some drawings that never made it. When we came upon the CS17 with the raised deck, Alan became excited by it's potential.
I cyber dusted off the oiginal drawings and imported them into Rhino and modified them a bit to fit my current thinking. Then I thought, this might work on the CS20. The CS20 mk3 was born. Here are a couple of views of her.
Posted by oldpropfan on 30 August 2014 - 04:54 PM
Posted by Designer on 22 July 2014 - 06:20 AM
I want to thank everyone for their support and well wishes. Carla got out of surgery at around 5 pm yesterday. The doctor said that everything went well. Marissa and I drove home after they moved her from the post-op to a room. She as alert and able to communicate and all of her vitals looked good. Beth is staying with her. She can come home in three to five days depending on her recovery rate.
The bad news is that they were originally going to repair the upper and lower spine at the same time but decided the the upper was so bad that they addressed it first and she will have to go back for a second round once they deem her to be ready. She will be convalescing for a long time.
Marissa is home from college and will be running the office as best as she can. I want to thank everyone in advance for their patience.
Posted by PAR on 14 February 2014 - 09:03 AM
Long boards come in various shapes, lengths and sizes, usually geared to match the job. A 1/2" plywood board is too stiff for most boats, except in large expanses of relatively flat areas. I've got a number of boards, one of my favorites is made from 1/8" Lexan. It's 4" wide, about 20" long and fairly flexible, so I can work compound curves. I have ones that are 1/8" and 1/4" plywood too and even one made from 14 gauge aluminum sheet. I buy paper on rolls and cut to length, using a spray adhesive to mount them, though you can just as easily use a clip or slot at each end, to hold the paper to the board.
Technique is key with a boogie board (board-'o-pain). Typically you work from one end of the area (or hull side) in a single direction, across it's full length. You select an appropriate angle, which often seems to be about 30 degrees to the centerline and stroke the board at this angle the full length of the area. All strokes are at this angle, leaving a series of angled scratches. You then come back at the opposite angle, in the other direction, netting a cross hatched pattern of scratches. The low spots will be clearly visible, not having scratches in them and the high spots will be knocked down a touch. At this point, you mark the low spots and apply a little filler in these areas. The next pass with the torture board is focused on the now filled low spots, so you can knock them down to surrounding areas. I often use a very light dusting of primer at this point to fine tune the surface and help see what needs what. Again, working a common angle, you run from one end, to the other, placing a new diagonal scratch pattern and come back on the reciprocal angle for the cross hatch pattern. Each pass will continue to knock down the high spots and reveal the lows you've missed on previous passes.
A pro will make three passes with the cross hatched, long board pattern. The first to find the lows, the second to knock the lows back once filled and the final pass, to even everything up. The backyard fairer, can make a career out of this process, with many passes and filling sessions. The more you work this set of steps, the fairer and smoother the hull will be. The same process is used with paint, if you want a baby's butt surface, just with finer grits, usually wet. It helps a lot to have the right lighting for this process. You can have too much light, particularly if it's directly over head. You want a low angle of light, so you can see the shadows in the low spots.
The biggest mistakes novices make are not using a long board, thinking a palm sander or orbital will do and over working the surface. The Harbor Freight "in line sander" linked above shouldn't be used. It will remove material at an alarming rate and it's not flexible enough to conform to curved surfaces. That particular Harbor Fright tool is a single piston design and you'll be in serious pain, with just a 1/2 hour of use. It's a real piece of crap and if you want one, get a duel action/piston design so it doesn't tear your elbows off. Try not to get aggressive with material removal, just lightly scratch the surface, so you can see what's high and what needs to be filled. On plywood hulls you'll bring the lows up to the highs for the most part, so skim coat the lows with some filler and knock these filled areas back locally at first, then with the long board passes. A jitter bug (palm sander), DA or orbital sander will not fair a surface, just smooth it. Fairing and smoothing operations are wholly different. The long board fairs. Once the surface is fair, then you can move onto smoothing operations. Fair is what you can see, while smooth is what you feel. A surface can be smooth, but quite unfair. A dent in a car door is a classic example of this. The dent can be polished and really smooth, but the light reflection will clearly show it's not fair.
Posted by Designer on 30 January 2014 - 10:27 AM
Posted by Howard on 29 November 2013 - 10:45 AM
Not entirely sure I understand the source of "shear" load, so I drew up some sketches of this to better visualize what is being suggested.
As I understood Graham and Travis's comments on what happened, if the pivot pin is not tightened to take out all the side to side slop, when the mast bends under load, only one side of the tabernacle takes the load, thus transferring most of the leverage force to the leeward side of the tabernacle. Essentially, the top of the tabernacle then becomes the fulcrum, and the end of the long lever that is the mast then ends at deck level. Under the load of the long lever, the entire face of the centerpiece is in tension and if enough load is applied........easy to do with the vastly increased leverage.....the fulcrum is what gives way and bends, taking a segment of the centerpiece with it when the centerpiece splits.
(Howard's Edit: Side to side slop does not appear to be the primary issue. Loose bolt is. A tight bolt shares the push on the leeward upright with pull on the windward one. Loose bolt does not. Side to side slop is still an issue as the push and pull levers against the fixed centerpiece to the side with a racking force or turning moment........close fit is still needed).
If the pivot pin is tight, both side uprights share the load equally. The force in tension transfers from the centerpiece to the outside edge of the windward upright and the whole apparatus starts acting more like an I-beam. The top of the tabernacle then remains an extension of the mast, and the fulcrum moves down to deck level, with the end of the long lever going all the way to the keel.
Not sure where "shear" load factors into this. I can see how a flat or plain sawn centerpiece would resist side to side bending better than vertical grain or quartersawn, at least in the middle, but I would not think that to be the case on the ends.
The affect from several wraps of glass around the joint essentially works to immobilize the joint, tying both sides together much as the pivot pin does. The strength of the glass handles all the forces of tension and compression to hold it together?
Lastly, there may be an additional force I have not considered and that would be in a vertical plane acting on the sides.. Perhaps when the mast bends, there is a compression force pushing the pivot pin down on the leeward side and an equal force in compression pushing up on the windward side as the mast attempts to rotate. The epoxy bushings take that load and spread it over a wide area of the upright.
But back to those "shear" forces, I'm still not certain where the loads are coming from that a flat sawn or plain sawn board is going to help overcome? Not doubting, just trying to understand.