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Dec 05, 2012, 10:43 AM
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Originally Posted by Gravman
Looks great. Are you going to use a triple drive trian like the original or just a single screw?
Gravman, No, I'm going to build it stock with the single screw using the running gear from Dumas. However, I'm going to use a Suppo 2212 920KV brushless outrunner motor and a 2 cell Lipo battery for power.

Been feeling my way around brushless power for several Dumas offerings and am starting to get a bit of a feel for how to size a brushless motor to a given boat size and type. The one thing thats becoming very clear is that you need a whole lot less motor then one might think when going brushless, especially on a boat like the Washburn Tug, and no doubt this one as well.....

PAT
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Dec 05, 2012, 10:52 AM
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"Glassing" the Hull


The hull was fiber glassed using 2 oz. cloth and West Systems epoxy resin thinned about 20% with denatured alcohol. The idea is to get a good soak into the cloth -- not so thin that the wood soaks it all out of the cloth, and not so thick that it puddles on the cloth and doesn't penetrate.

The hull was done in one big piece with a small patch on the stern. The cloth was split along the keel at the bow and trimmed along the curve after wetting. The scrap cut from the bow was used at the stearn and trimmed after it was wetted as well.

As it turns out, up to this point this has been the easiest build I've ever done from a Dumas kit. The planking was a breeze, went quickly and easily. The glassing process was virtually effortless with no problems in making the cloth conform and stick to the surface. So far, the kit gets an A+.
Dec 05, 2012, 11:09 AM
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Planking the Deck


While the resin was curring on the hull I decided to plank the deck. Now there is a note in the instructions indicating that the sub-deck might be a bit narrow for the hull, so all the planks were added, except the outer-most one on both sides. The planks were sanded level with a vibrator sander, but won't be varnished until after the deck is glued in place and the outer planks added and sanded to final shape.
Dec 05, 2012, 11:16 AM
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Trimming the Cloth


After the hull had curred overnight the excess cloth was trimmed from around the top of the hull. The front end was sanded at the keel and the top edge sanded flush. Next up will be to get the running gear and external keel set up, then wet sand the hull and get a coat of spot glazing putty on and sanded to prep for primer.

But in the meantime, the deck was fitted, and sure enough it's about 1/8" too narrow on both sides. Will fill the void after the deck is glued in with balsa sticks, then add the last planks and finish sand and seal the deck.

Stay tuned, more coming real soon... This is really starting to get FUN!!!

PAT
Dec 05, 2012, 05:39 PM
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Quote:
Originally Posted by Gravman
Looks great. Are you going to use a triple drive trian like the original or just a single screw?
The WW I version had 3 screws where the WWII hull had a single screw. The Dumas hull is modelled after the WW I boat.
Last edited by green-boat; Dec 05, 2012 at 11:02 PM.
Dec 07, 2012, 06:35 PM
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Installing the Stuffing Box


The keel was drilled with a long home-made drill bit. Then the tube was marked, slipped into the hole, aligned and tack glued with thin Cya. The strut was bent to shape, fitted, and soldered to the tube. Once all that was done, the keel was sealed inside and out with a slurry of 15 minute epoxy and micro balloons.
Dec 07, 2012, 06:37 PM
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Fixing a Slight Mis-Match


After the stuffing box was in and cured I ran the prop shaft in and found that it hit the frame, so a small cut-out was made with a Dremmel sanding drum to eliminate the interfearance.
Dec 07, 2012, 06:41 PM
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Fitting the Deck


The deck had been previously planked while waiting for the resin to cure on the hull. Now the deck was aligned and glued in place, the inacuracies around the edges filled with balsa sticks and the outer-most planks glued in place. A final sanding was done to true up the planks and 3 coats of Nitrate dope brushed on to seal the wood.
Dec 07, 2012, 06:45 PM
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Fitting the External Keel


The external keel sections were shaped and glued in place. The bow section was laminated from 5 pieces of 1/16 X 1/4 bass wood. The strippes were joined at one end, then soaked for about two hours to soften the wood. The stack was glued in place at the center keel and one strip at a time formed around the bow and glued in place and allowed to dry overnight.
Dec 07, 2012, 06:53 PM
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Contouring the External Keel


Once dried, the bow section was carved to shape and the edge gaps filled with Bondo. Then a a slurry of West Systems resin and micro balloons was applied along the entire keel and using a "clibrated finger" the slurry was pulled along to fill and contour the keel into the hull. The remaining un-treated wood was sealed with thinned resin to complete the process.

At this point the bottom side is just about wrapped up. The only thing left now is to squeegee spot glazing putty onto the entire outer surface and sand to prep for prime and install the rudder bearing tube.

So far all has gone well, the only hitch being the frame interferance with the prop shaft that was easily fixed. Otherwise, no problems at all. Stay tuned, lots more to come.....

PAT
Dec 09, 2012, 10:10 AM
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Setting Up the Rudder


The rudder was built up per the instructions and detail drawings and soldered together with lead free solder. The joint was cleaned up with jeewlers files and polished with fine steel wool.Then the rudder bearing tube was fitted and glued into the hull and faired with a dab of 15 minute epoxy. Once cured, the entire hull was squeegeed with a thin coat of red spot glazing putty to fill the weave on the cloth.

Then it was off to the boat pond to play while the putty dried..
Dec 09, 2012, 10:17 AM
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Adding the Rub Rails and Bulwarks


The hull was sanded to remove exess the putty, then the rub rails were added. The instructions for locating both the upper and lower rails are clear and concise, so it's just a matter of marking and gluing.

In reading ahead to the section on gluing up the bulwarks I really thought that those were going to be a real pain since they are edge glued on tip of the deck. However, it turned out to be real easy to aling them along the rub rail and apply small omounts of thin Cya to stick them in place. Then once the rub rails and bulwarks were all in place the wood was sealed with thin Cya and lightly sanded.
Dec 09, 2012, 10:24 AM
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Very nice Pat. That hull looks great. Kinda sad Dumas did not go the extra effort and provide balsa long enough to cover the full length. Bean counters at work.
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Dec 09, 2012, 10:30 AM
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Fitting the Kleets


The kleets are laser cut from 1/32 ply and are glued to the bulwarks inside and out in 10 places using small stationary clamps to hold them in place while small dabs of thing Cya were applied. Then once the parts are glued in place the openings were done by first drilling both ends and sawing into the top edge. Then the remaining wood was cut out with an X-Acto knife and the opening cleaned up with round and flat jewelers files.

And lastly, the deck combing was added to complete the hull assembly. Next step -- primer. and then it's onto the deck assemblies.

PAT
Dec 09, 2012, 10:38 AM
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Originally Posted by Gravman
Very nice Pat. That hull looks great. Kinda sad Dumas did not go the extra effort and provide balsa long enough to cover the full length. Bean counters at work.
Graveman, There are two factors at work there. One is the standard box length, the other is standard balsa length. To go up to 48" wood and a box long enough to accomodate it, or worse, a non-standard wood length and a custom sized box would be far more detrimental then the need to make a few scarf joints.

Considering the market place these guys have to work with in today's "non-modeling" world, my hat is off to them for the efforts they've made in providing us with some really cool stuff to build.

PAT


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