For the very latest activity, click here: From a Bare Hull

Monday, March 31, 2008

Fiberglass Tank Fabrication Part II

Did some more work on the tank this weekend. The edges of the tank were faired with compound, sanded smooth, then painted with epoxy to give a slick surface. Then, glass was cut and fitted. Two layers of glass. Also, "bulking material", was added in each panel. This material is a spongy sort of material that is designed to be inter laminar. It absorbs resin and provides extra stiffness when cured. Over the glass goes the peel-ply, flow medium and the bag. Implosion! Once the vacuum pump was attached, turned on, and leaks around the sealing tape fixed, the bag started to implode the mold. This meant that there was an air leak into the inside of the mold. Something I was hoping would not happen. No worries, it can be salvaged. Details coming soon. Stay tuned for part III.

Friday, March 28, 2008

More Heavy Metal

It has been a while, but you may recall we have been working on a rudder. We have been waiting for the final, and most expensive piece of the rudder frame, the upper rudder stock. Well, we finally picked up that piece from the (very busy) machine shop. It is about 3 feet of 2 1/2 diameter Aquamet 22 stainless steel shafting. Tapered on one end to fit the 60mm rudder bearing and bored on the top end to recieve an emergency tiller fitting. The pictures here show the "dry fit" of the other pieces before we send it off to get welded next week. Once welded together the rudder frame will give a starting point for assembling the steering mechanism, of which I have a few more engineering details to work out.

Monday, March 24, 2008

Fiberglass Tank Fabrication Part I

The space we have planned for holding tank for the forward head is somewhat of an odd shape. Vendors like Ronco Plastics have all sorts of polypropylene tanks in various shapes and sizes, but they don't have anything that comes close to this. So I decided to try my hand at fiberglass tank construction.

There are all sorts of info on the Internet about constructing tanks via hand-layup. But I thought this would be a good opportunity to get more experience using vacuum infusion, seeing as we have all the materials and equipment.

So, this past weekend, I started building the "plug" that will be used to mold the tank. First picture there is the wooden frame. The one on the left was a hack job I first tried, which I didn't like. The one on the right is the final version. Frame is simply made of wood and held together with hot glue and brads. The frame needs to be sturdy to withstand the downward force of the vacuum bag such that it doesn't flex, or worse, crush.

The panels over the frame is Masonite. The version that has the slick white finish on one side that is used for dry erase boards. The slick surface is good for releasing the part when the resin has cured.

The edges were trimmed down with a chisel and given a generous round over with a router. The important part is that the surface of the mold must be sealed air tight. Not so much to prevent air leaks (there wont be the way it will be infused), but to prevent resin from leaking into the interior space of the plug, which could be disastrous for the infusion process. So, the gaps along the edges are filled with a two part filler or fairing compound to give it a good seal. Just about anything could be used here as long as it can be sanded smooth.


Stay tuned for part II.

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Saturday, March 22, 2008

Off Topic: Marine Fuel Cells

(thought I would blog about some small topics more often. Topics that come up during this Westsail design/build process, but are not neccesarily directly related to the Westsail. Sort of a "thought of the day" posts) This was forwarded to me by my wife. Maxpower is a French company that makes marine fuel cells. A hot topic in this day of global warming and high oil prices, fuel cells generate electricity via an electrochemical process instead of electro-mechanical (i.e. conventional alternator/generator devices). This particular range fuel cells can directly replace conventional batteries and/or be used to charge a conventional battery system. These fuel cells run on methanol and have very few moving parts.
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Monday, March 17, 2008

Local Boat Show Weekend

There was a boat show happening this weekend down at the marina here in town. We browsed some boats to help get more ideas. In particular, interior ideas. There were only a few production sailboats there, but we noticed all of them had this particular type of cabinet latch that we liked. Shown here, it is a push-in/push-out latch. This particular one requires the button to be pushed in in order for the cabinet to be locked. Pushing the button out allows the cabinet door to freely swing. SeaDog and Sugatsune make versions of these latches. But we saw a variant on on of the boats (cant remember the boat builder, except it was in Slovenia) that also required a "twist" on the pushed-out button in order to open the cabinet. Anyone seen a maker of these latches? Also of interest, a used Pearson 51 cutter that had the original teak caprail replaced with stainless steel plate (full perimeter). Looked nice, but that really must have cost something.
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Saturday, March 15, 2008

Mechanical Drawings Updated

Some of the drawing PDFs (see sidebar links) have been updated. Recently started mocking up the forward head in doorskin to verify sizes and proportions. After standing in front of it in the boat and having discussions, the general layout seems to be what was visioned on the drawing. Got some new ideas for finishing work (still a ways off), but now we can at least start planning for head plumbing as it appears we will have space for the system we want. Related to the forward head, the holding tank will be an odd size and no company makes a tank off-the-shelf that is even close. So, I will be drawing on my experience (?) with resin infusion to make a custom fiberglass holding tank. No, I could lay it up by hand, but this will give me more experience with infusion and mold making. As it is just a holding tank, any cosmetic screw ups are no big deal. More on that later.
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Tuesday, March 04, 2008

Thoughts on Stern Pulpit

How can you easily accommodate a boarding ladder, dinghy davits, clear side decks, and still have reasonable mounting space on your stern pulpit for other safety gear and doo-dads? And still have it fit the lines of the boat? The drawings below is what I have come up with so far. Idea taken from the design of a similar shaped boat pictured at the bottom. The idea is essentially a swim step "elevated to deck level" that "wraps around" the stern. Integrated into the step is a hinged boarding ladder that can be "dropped". The frame for the step is high enough such that simple davits can be installed using blocks (pulleys) to raise and lower the dinghy (when coastal cruising). With the boat being a ketch, the step can extend aft enough to provide end-boom sheeting for the mizzen (gives best mechanical advantage). My wife is not sure about it, but I think it looks decent. Certainly better than a big radar arch and/or hinged/folding davit structures for the dinghy. No?

Monday, March 03, 2008

Fiberglass Boatbuilding ain't "Pretty"

The idea for this post came to me after reviewing the pictures for the last few posts. Some may have a notion that there is something "romantic" and "artistic" about "building a boat". Well, that may be true if you are building a traditional WOODEN boat. Let me tell you it is not the case if it is a FIBERGLASS boat. There is nothing pretty or elegant about building a fiberglass boat. To the untrained eye, the process is one big dirty, dusty, ugly, sticky mess! And for the most part, it is. The most obvious visual detractor is the "collision of colors". All the different glues, resins, composites, etc come in different colors. And when they are put together, things tend to look a bit psychedelic. Some examples of the materials we are using... Adhesives
  • white = 3M 5200
  • orange = Loctite Methacrylate Structural Adhesive
  • grey = Plexus Methacrylate Structural Adhesive
Resins
  • whitish-clear = West Systems Epoxy
  • dark pink, dark brown = vynilester resin (depending on the vendor)
  • yellow-grey = original hull layup of polyester resin and glass
  • light green = Corebond
Fillers
  • white = silica
  • rust-brown = fairing compound
Rigid Materials
  • grey = coosa board
  • wood = marine plywood
  • green = airex structural foam
  • white = airex foam corner fillets
Construction Marks
  • white, yellow = paint markers
  • black, blue, purple = sharpies (used for marking glass)
Combine all these colors, sprinkle with a fine dust from a grinder, and what you end up with is all the psychedelia you see in the pictures. Better than acid I am sure (not that I would know of course). Like it said, it ain't pretty. This is why God created "paint", to cover up all this stuff when the finishing work begins (that is about as religious as you will hear me get).

V-Berth Roughed in (Finally)

Recall from a previous post that the V-berth was roughed in save for some glass work. Well, with the newly stocked fiberglass and resin, I was able to finish the glass work. This involved glassing in the aft cleats against the hull to support the berth's surface. The base support of the cleats are shaped from Airex foam with a top piece cut from Coosa. The Coosa will provide better "bite" for any tapping screw for hinges that we may want to install. Generally it went like this
  • shape the airex foam and coosa to the hull. Miter the ends and route a generous round over on the exposed edges.
  • apply corebond to the surface of the hull where the cleats will be attached.
  • Generously wet out the surface of the foam.
  • Set foam into the corebond. Spread out and/or remove excess corebond with a putty knife.
  • Layer wetted glass over the foam and against the hull.

Rudder Bearing is IN!

Completed the glass-in of the rudder bearing housing this past weekend. As mentioned in a previous post, the housing is made from FR-10 tubing (thermoset epoxy) and is about 1/2 inch thick. The inside has been turned to receive the diameter of the 60mm self-aligning rudder bearing. The tube was cut to closely mate with the hull. Lateral and aft reinforcement plates made of G-10 sheet was glued to the outside of the tube and hull providing sideways and fore/aft reinforcement. All this done with an alignment rod keeping the bearing (and housing) aligned with the lower gudgeon. As this component is a critical piece (it will bear most of the side loads on the rudder), the final glass-in was done with epoxy. Epoxy provides for stronger laminates over vynilester or polyester resins. This was the first time I had done any significant lamination with epoxy (so far, most glass work has been with vynilester resin). Considering my recent post on tabbing in bulkheads (done with vynilester), I should say working with epoxy is MUCH different. Epoxy resin is generally thicker (I am using West Systems brand) therefore, it takes more work to wet-out the fabric. Apparently there are glass fabrics specifically woven for use with epoxy. It can be thinned with something like acetone, but, according to West System, strength will be proportionally compromised. Generally it went like this
  • stuff thickened epoxy (milled fibers and silica) on the inside base of the tube to fill gaps between the tube and hull, and provide a smooth fillet.
  • at the outside base of the tube, smooth out the thickened epoxy that squished through.
  • glass the tube and reinforcement plates to the hull by laying two layers of glass strips around the base of the tube and along the base of the plates.
  • fill and smooth the joints, over the recently laid glass with more thickened epoxy, such that any fillet is very shallow and barely shows.
  • Glass over the entire surface of the tube and plates with two more layers of glass, staggered, giving it a large footprint on the hull surface. Align such that the the fibers give as much "radial" coverage from the center of the tube as best you can (to provide for strength under load).
  • Once the epoxy is set, burr off any sharp edges with a grinder.

Saturday, March 01, 2008

Got Glass?

300 Pounds of Fiberglass

We ran out of bulk glass last week. The last time we ordered this stuff it was sold in quantities measured by the yard (that order was about 50 yards). I thought that was a lot then, but with less than 25 percent (approx) of boat project jobs requiring glass complete, It appears we will need more than 50 yards this time.

Having said that, and, with our discontent with our last supplier (I won't name them), we placed this order with Composites One. They are a larger company supplying many of the builders in the area. We get a better price break, but there are minimum quantities to buy. They don't sell reinforcements by the yard, only by the roll. So, we got two rolls of knitted bi-axial fabric One is a 45/45 degree weave, the other is 0/90 degree. Nearly 300 pounds (maybe 200 yards-ish).

Also with the order, a ten pound bag of silica (resin thickening agent), 5 gallons of V/E resin, 4 cartridges of Plexus structural adhesive.

This should keep us going for a while.

Thanks to my wife who knows all the industry contacts and places the orders for this stuff. If it were me handling this, it would take much longer.
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