#70 - an amateur kit build

The place to discuss SCAMP (Small Craft Advisor Magazine Project), our 11' 11" micro minicruiser.

Moderator: Moderator

Post Reply
Monies
Recognized Old Salt
Posts: 805
Joined: Sat Nov 20, 2010 8:39 pm

Re: #70 - an amateur kit build

Post by Monies »

This is just a supportive comment- I think it is impossible to have too many photos or tips for builders. Most people wish that everyone building would post tons of photos and building advice.

People still write me directly for advice on boats Mike built several years ago and we could probably do a revised build story with an album of photos and people would still write in for more!

Don't worry that you're over doing it!

Jackie Monies- The Red Scamp
JohnT
Regular Contributor
Posts: 154
Joined: Sun Jan 29, 2012 1:31 pm

Re: #70 - an amateur kit build

Post by JohnT »

The Manual seems to indicate that the entire rudder blade and entire centerboard are glassed. I'm not entirely clear as to how the authors did this. I plaln to ease the corners on the rudder head. I also plan to run a strip of cloth along the leading edge and top of the rudder and then glass each side, rolling the cloth around the leading edge and trimming the trailing edge while the resin is green. This will give me 3 layers of glass on the leading edge and a reasonably sharp trailing edge. The same approach should work on the cb.

There are many ways...

You're a little ahead of my build on #95. Please let us know how your glassing works out.
User avatar
simeoniii
Recognized Old Salt
Posts: 700
Joined: Thu Oct 21, 2010 5:55 am
Location: Port Ludlow, Washington

Re: #70 - an amateur kit build

Post by simeoniii »

Illustrated Centerboard Build -

Dan & John et al,

First to answer Dan's earlier questions regarding F/G cloth.

If going on bare wood, pre-coat the wood with epoxy so it will soak in and not starve the cloth . Apply the cloth on top of the coating. If it's a small easily managed piece/area, it okay to go right on with the cloth while fresh or even tacky to "green" stage. To me, green means rubbery and still easily cut by blade or even scissors when it comes to overhanging coated F/G cloth. For bigger areas, you might want to let it harden beyond tacky so you can still move the cloth around as necessary.

For already coated areas like your B-1 bow transom, just sand off the gloss with 80 grit and tack off the dust with a damp (water) lint free cloth, then, when dry, you can either apply a light base of fresh epoxy to lay the cloth on, or easier yet, just wet out the F/G cloth straight through the weave, then squeegie the excess off until it's smooth and almost "dry".

John, your planned approach should work fine. Now that I think about it, I didn't put any F/G cloth on the upper front edge of the board's shoulders, above where the contouring starts. It will probably not present any structural issues in the future :oops:

The entire centerboard and rudder should be glassed. You should round/ease the CB transition area where the flat head of the board transitions to the contoured area. If the cloth is going to tend to lift or float anywhere, it's on leading edge area of this transition. Don't worry about the trailing edge of the board/rudder. It is pretty sharp after gluing. I squared mine off with 80 grit so it was maybe 1/8-3/16" wide. When you glass the foils, support them leading edge up (horizontally) and let the cloth fall on either side several inches below the trailing edge. Wet this out with epoxy an inch or so beyond the board and plan on trimming it close to the board (1/8"?) while it is still in the green stage. Later, you will want to fill this slight void with thickened epoxy before covering with Dynel, if used, otherwise when you are doing your fill/fairing coats. On the rudder, after it is glued together, you can sculpt off excess material on the protruding uphaul area so that it more easily matches the trailing foil.

I glassed the head of the foils with a layer of cloth over the top and down a couple of inches to a horizontal band of masking tape. Then, while green, take a straight edge & blade and trim straight across at the edge of the tape. I did this with the foils clamped vertically in a wood vice, everything below draped in plastic. After this has hardened and you do the rest of the board, reverse the process and overlap the other way. You will get a nice neat join. I put a single layer of glass across the top, and a double layer, wet on wet, over the bottom part of the board. Then I think I finished with another single across the top.

To do the hard part of the CB, I had it suspended horizontally from the work bench. I had a vertical 2x4 in the vice, from the floor up to a bit above the highest part of the board. I then used long (6") exterior construction screws through the 2x4 and into pre-drilled holes in the head of the board. I did likewise at the foot of the board through another vertical 2x4 with legs/braces at the bottom to stabilize it. A this point, with the lead in, it's a brute of a board to man-handle. I figured out how to do it solo but an extra set of hands is suggested. Keeping the screws well protruding from the 2x4 to give yourself room to work the cloth presents a problem. I supported under each screw with a small block to wood to support it. Layer I dowelled the voids left by the screws and trimmed them and covered well with thickened epoxy.

Now for some photos. Disclaimers: These shots are of a prototype "kit" centerboard foil. Notice it is not slab sided but a full NACA profile. Because more wood has been removed in the shaping, it weighs 12.22 lbs vs 13.84 lbs for the regular kit foil. That brings on a whole different scenario when it comes to routing out cavities in the thinner board to hold a sufficient amount of lead. You will notice another hole through the board. I'm engineering a downhaul/hold-down line for the board and using a lighter fill of lead. There is also a routed groove on the top (head) of the board to provide line clearance between the board and the forward trunk log.

I'm also experimenting with adding graphite powder. In the final coat I used, by weight, the same amount as the amount of resin in the epoxy mix. Earlier, when filling and fairing the board, I added 406 coloidal silica and 404 high-density fillers to the mixed epoxy.

The designer white patch is yet another experiment. I added white pigment to the resin, mixed well, then added the hardener. By weight, I added the same amount of pigment as the weight of the resin. This made it almost completely opaque. I ended up with two coats for good coverage.

For fitting the F/G cloth around the bottom edge of the board, remember you can cut darts and slits and what ever to make it fit & lay down. However you do it, try not to get any voids. If you do, you can later fill with thickened epoxy. Without a doubt, this is really the messiest bit of the build. I've done three of them and it's alway a hash.

Also, after the two layers of F/G cloth, I applied a single layer of Dynel cloth strips on the leading/trailing edges, and multiple bias cut strips across the bottom. I've never used Dynel before but it is supposed to be very abrasion resistant. I can say that it really soaks up epoxy and becomes very sponge-like and pliable. I filled the Dynel on the bottom of the board with my graphite mixture. Then I went on to fill and fair the board.

Pictures, three at a time, always presents a challenge ;)

Simeon
You do not have the required permissions to view the files attached to this post.
Last edited by simeoniii on Wed Dec 05, 2012 9:06 pm, edited 2 times in total.
Simeon
Voyaging with Noddy, #11
User avatar
simeoniii
Recognized Old Salt
Posts: 700
Joined: Thu Oct 21, 2010 5:55 am
Location: Port Ludlow, Washington

Re: #70 - an amateur kit build

Post by simeoniii »

Illustrated Centerboard Build - continued
You do not have the required permissions to view the files attached to this post.
Simeon
Voyaging with Noddy, #11
User avatar
simeoniii
Recognized Old Salt
Posts: 700
Joined: Thu Oct 21, 2010 5:55 am
Location: Port Ludlow, Washington

Re: #70 - an amateur kit build

Post by simeoniii »

Illustrated Centerboard Build - continued
You do not have the required permissions to view the files attached to this post.
Simeon
Voyaging with Noddy, #11
User avatar
simeoniii
Recognized Old Salt
Posts: 700
Joined: Thu Oct 21, 2010 5:55 am
Location: Port Ludlow, Washington

Re: #70 - an amateur kit build

Post by simeoniii »

Illustrated Centerboard Build - continued
You do not have the required permissions to view the files attached to this post.
Simeon
Voyaging with Noddy, #11
User avatar
simeoniii
Recognized Old Salt
Posts: 700
Joined: Thu Oct 21, 2010 5:55 am
Location: Port Ludlow, Washington

Re: #70 - an amateur kit build

Post by simeoniii »

Illustrated Centerboard Build - continued
You do not have the required permissions to view the files attached to this post.
Simeon
Voyaging with Noddy, #11
User avatar
simeoniii
Recognized Old Salt
Posts: 700
Joined: Thu Oct 21, 2010 5:55 am
Location: Port Ludlow, Washington

Re: #70 - an amateur kit build

Post by simeoniii »

Illustrated Centerboard Build - the last

The end... (for now)
You do not have the required permissions to view the files attached to this post.
Simeon
Voyaging with Noddy, #11
User avatar
simeoniii
Recognized Old Salt
Posts: 700
Joined: Thu Oct 21, 2010 5:55 am
Location: Port Ludlow, Washington

Re: #70 - an amateur kit build

Post by simeoniii »

Illustrated Centerboard Build - the last, really!

The very end... :D
You do not have the required permissions to view the files attached to this post.
Simeon
Voyaging with Noddy, #11
Bcbimmer
Recognized Old Salt
Posts: 587
Joined: Sat Jan 07, 2012 11:12 am
Location: Victoria, B.C.

Re: #70 - an amateur kit build

Post by Bcbimmer »

Thanks Simeon, Very useful description. When I glassed the fin on my rowing shell did it in a fashion much like Johns description. Much smaller scale but principles the same. Love the color on the CB. Paint your SCAMP in a similar pattern and you could end up with an amorous Killer Whale helping with a capsize test. Watched a friend and his son in an old wooden double rowing shell trying to outrun a Sea Lion in rut. Still has the bite marks in the stern of the boat to prove it.

Cheers,

Dan
Post Reply