cabin mold between the hulls

I never thought a 60 ft. shop would seem small but I actually had to lift both hulls up a couple of feet so that I would have enough room to build the cabin mold. Scribing all the lines onto the mold forms using carbon paper and the full size templates is an exercise in patience. I was only able to build, scribe and cut two or three molds per day during the week but a full week end allowed me to set them all up on the strong back and lay down the stringers. Note: I had to resort to using double plywood strips in the high curvature areas. A strip of 5/15 in ply topped with a strip of 1/4 inch ply added up to be close enough to the same thickness as the 3/4 in stringers.

taking shape

I couldn't resist the opportunity to flip the port side hull up and position it in relationship to the starboard hull. The cabin bulkheads that protrude from each hull are sticking up like fangs. The edges of these bulkheads are 112 inches apart. Note: the port side bow lacks the solid foam stem section so you'll need to use your imagination and pretend you see a sleek pointed bow piercing through blue green tropical waters.

laying out the cabin form frames

Using the full size cabin templates provided with the plans package, the temporary form frames are being marked onto 3/4 in. chip board. There are about a dozen of these form frames that define the shape of the cabin. Once I cut them all, I'll set them up on the same strong back that was used to create the hulls. When complete, I'll run stringers to create a female mold to which I'll thermoform and fit the one inch corecell structural foam.

on the spot vac bagging

Here's a quick way to bond the additional layers of reinforcement glass where the bow cables will attach. I'm vacuum bagging two layers of unidirectional glass and a square of reinforcement tape over the exterior triaxial glass and the high density insert. It calls out for additional reinforcements on the inside as well

F-44SC Catamaran: a cool fat tire cub

http://www.waaamuseum.org/

a cool fat tire cub

Ok....so this doesn't have so much to do about the catamaran but Its always nice to think about alternate forms of transportation......The little Hood River airport is home to about 20 piper cubs that are tucked away in the hangars that line the airstrip.. Also, right down the street from the shop, a nice collection of antique aeroplanes and automobiles can be seen at the new Western Aeroplane and Automobile Museum.

http://www.waaamuseum.org/

laying down the glass

So a Saturday and part of a Sunday finds the port side hull clad in nice smooth glass. Again, peel ply tops the epoxy and glass and makes it possible to work the resin out and helps insure a good bond between the foam and the glass. My process goes like this.....smoothe the foam, skim coat with micro/epoxy mix to fill the foam surface. roll on a good wet coat of epoxy, lay down the glass, roll on another good wet coat of resin, top with peel ply and work the layers down with a bondo spreader from stem to stern.

help....

It's nice to have a little help now and then. 44ft. long lengths of 32oz. tiraxial glass is a bit hard to handle so four extra hands makes the job of laminating go much faster.

laminating the exterior, inboard, port side bow

Here's a photo taken while standing one the inner port side hull looking forward. The hull is laying on its side in three cradles. I wanted to glass the hull sections with continuous lengths of glass from stem to stern and you can see the recess strip created with a power planer that allows the triaxial glass seams to overlap flush.

Checking the fit.

another shot looking back into the port side hull. (The outer hull section is on it's side) the inner port side hull section is hanging from the shop rafters in prep for bonding all the seams with a mix of epoxy, aerosil, micro and a little chopped glass fiber.

bonding the port side hull

Fitting the port side hull halves.

starboard hull hanging in the breeze

Here's a picture of the mold being broken down while the hull is suspended from the shop rafters. Notice the stack of mold forms in the lower right hand corner of the photo.

disassembling the mold

Next step........reaching around and unscrewing all the screws that hold all the stringers onto the mold forms.

lift in process

Here's the hull being lifted off the forms. Notice the plastic strips that were placed along the plank seams to keep excess glue from sticking to the stringers.

lifting the starboard side hull

Finally........time to lift the starboard side hull off the mold. I first used an automotive jack and a length of 2x4 placed under the forward bulkhead and lifted the hull about two inches off the mold. This gave me enough room to slip lifting straps under the hull in three places. Using three chain hoists strapped to the rafters, I then lifted the hull about a foot high to provide access to the screws that hold the stringers to the mold forms.

timing the flow...

sometimes it's possible to get an idea of how things are progressing during an infusion by marking saturation lines and timing the progression. Above, you can see the start, 3 min line and the six min line. ....notice the distance betweent the 3 and the 6 is slightly shorter than the start to 3. That's an indication that the resin is slowing down due to its' increasing viscosity.

another little resin infusion clip

pulling resin into a vacuum bag ( resin infusion) is a lot cleaner than wet layup / bagging but it takes a little practice and a bunch of mistakes to learn how best to set up the flow.

It's easy to dive off the deep end into developing technique and experimentation but it's still hard to beat a simple wet layup that's finished off with a bondo spreader and peel ply. ..........knowing when to use the simplest or quickest methods goes a long way towards insuring you keep the project rolling.

infusion clip

resin infusion with a parrot on your shoulder and a video camera in one hand is a bit of a challenge..........

resin infusion

Here you can see the resin being sucked into the bag. infusion requires a good deal of prep work and if you set things up right, it is a very pleasant technique that minimizes potential contact w/ the resin and it can be very neat to watch......it's just a matter of using 3M77 to tack all your dry glass in place, wrap the part w/ peel ply, decide how to pull your resin, build a periferial vacuum manifold, w/ a resin brake then tap the center so that resin can flow outwards.

In this instance, I din't get a full infusion but it's easy to just tap into the bag where it's dry and repeat the process until you get your part.

Parts do come out really nice when things go right......

infusing the starboard side rinterior rails

here's some prep work involved in doing a resin infusion of the interior side rails....these are 10 inch wide webs that have unidirectional glass on the edges that get's bonded into the interior of the hulls. Infusing with system III Silver tip is difficult at best. I find it to be too viscous but if you use plenty of flow media it's possible.