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Drew

Aussie CS 20-3#5 "Dragonfly"

141 posts in this topic

To CSIM, I picked up my materials through Drive Marine in Beverly Hills, Sydney. Dave Giddings is helpful and the ply was as good as you can get these days. I am using Bote Cote epoxy and liking it and Dave also handles a range of glass tapes, cloth etc.

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Hi Drew,

Bote Cote epoxy is my favourite. Have used West System, FGI and others and have found them all to be sub-standard compared to Bote Cote which has no amine blush.

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Alex, with the exception of very few, not very common formulations, all marine grade epoxies will blush, even the ones that say they're non-blushing. BoteCote is well regarded in your country and has a good reputation. It's physical properties are similar to West System 105/205 and System Three's Silver tip. If you have very controlled environmental condisions in your shop (air conditioning) and practice bagging and/or infusion techniques, you can assume Bote Cote is essentially blush free. If you are hand applying, without environmental controls, you'd be wise to assume some blush will occur and wash it off any cured surfaces.

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My past experience of epoxies is to take nothing for granted. Always prepare the surface well and wash down the finished epoxy before painting. Its no big deal. What I like about the Bote Cote is its genuine low toxicity. I still wear a full mask, but compared to the epoxies I used to build an aircraft, even the smell is more human-friendly. I use it with a range of fillers, but my favorite for fillets is flox. It sets like steel, so best to smooth it down while still very green or apply the tape wet-on-wet. 

After a few weeks away from boat construction I am back at it with a vengeance. Port and starboard sheers have been joined ready to install, all bulkheads are glued and taped and am about to trial fit the bunk supports. I'm putting off the tedious job of sanding the edges of all the taped joints ready for three coats of epoxy.

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I do have one question for the group. As I look at pictures of the sprit being used instead of a boom (eg the NIS series of cat-rigged sharpies) I wonder whether the sprit spoils the set of the sails at all and reduces the pointing ability? What is the experience of those whose boat is on the water?

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The sprit doesn't affect pointing ability, except in very light air. You'll notice a "fouled side" on these occasions, so you'll foot off a little, but once the wind is over a zephyr, you'll have no issues. The sprit can be curved in a half or full "wishbone" configuration which solves this issue, but it's still a cat ketch, which has windward limitations built in anyway. 

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A few years ago I saw a real world experiment with sprit booms. My brother had built a Bolger Gypsy which had the standard rig with a sprit boom. He entered a weekend regatta and another Gypsy was in the fleet. The only difference in the other boat was that the sprit boom was set on the other side so in theory one boat should have been better on one tack and the other boat better on the other tack. Both skippers were very experienced.

 

No one could detect any difference in performance between the boats on the different tacks over a few races. I think the effect of the sprit on the "bad" tack is very small.

 

Cheers

Peter HK

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Again, in very light air it's noticeable, but once you have a steady few knots, not so much and progressively as wind speed picks up.

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Thanks for the views on the sprit booms guys. Here is a question for those with Mk 3's. I assume that the bunks and the tops of the cockpit seats should both be parallel to the designed water line, and therefore parallel to each other and basically horizontal when afloat? Your experience on this appreciated as I am fine tuning the bunk bulkheads at the moment.

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If you really need to use the potty, then no one is going to care, if the bridge deck is paralleling the LWL.

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Despite being behind schedule, I am happy with the progress forard of bulkhead 3. Bilges have 3 coats of epoxy and all taping and fillets are done. Bunk tops being prepared and trial fitted prior to fitting hatch rings and coating with epoxy. Building from scratch means little inconveniences like butt joins have to be used but I am happy with the result. I ended up doing cabinet cuts in the butt joints in the bottom panels to ensure the sheet bent to take the shape of the hull. When the bunk tops are in place I will start on the sheer and cabin top.

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Time I stopped feeding off everyone else's great posts and stirred the pot a little. I have fitted bunk tops, taped and epoxy coated anything that stayed still long enough, although bunk tops are waiting for a final coat and sheer strakes are still to be epoxy coated. As you look at the photos, yes something weird is happening here. Graham's design is just what we need in a boat at the moment, but I prefer a smaller cockpit.

With that in mind I have sacrificed the bridge deck and brought the cabin ends aft to the cockpit forard bulkhead. That bulkhead is now a coaming and the top of the forard ballast tank is a step into the cabin. I topped it with 9mm ply and will glass it. The small amount of extra cabin that was previously the bridge deck will be a small galley area on the port side and a radio and chart area on the stbd side. Everything else is standard, but it also means we don't need a step taking up room in the cabin sole area. So everything is being trial fitted at the moment then, when it all fits with the same measurements, glue, fillet and glass! Progress at last!

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Very nice Drew !! And you still have stowage space aft of Blk 4.

Question: what's your arrangement for the CB tackle? I don't see box for the CB pulley and pendant at the top-fwd end of the CB well.

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The CB tackle will be unchanged from the plan, I just haven't got to it yet. The slot for the pennant coming out of the box still has glass over it which I will cut out when I install the pulley and build the box. It won't interfere with access to the cabin.

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Drew,...

I forgot to cut the slot in the top of the CB well before assembly of the module. It was much harder to do later -- I had to find an extension for my drill bit. I suppose I could have gouged it out with just a chisel. The construction manual warned the reader to do it before assembly and that was my plan -- but I forgot about it and got ahead of myself. BTY I'm not permanently putting down the cockpit decking or the footwell sole until almost the last thing AFTER the bottom is done and she's right-side-up.

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I routed out the slot when I built the CB box, but left it glassed over during construction to avoid rubbish settling through the slot and into the box. I will just cut the glass out with a sharp chisel when I build the pendant box and pulley setup.

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