A Place to Hang My Keel

   

So after all my floating, and recalculating, I ended up locating the keel box right where I had originally calculated it would be.  Which was great since I had already installed the main cross beam which now intersects the keel box perfectly!  I was still a bit nervous cutting that hole in the hull though...mainly because yesterday it floated so well, it just seemed a shame to put a hole in it!  The tricky part today was getting the boat leveled in all directions so I could be sure the keel box is installed straight on centerline, and plumb all around.  I think I was able to meet most of those criteria so I epoxied it in position.

Whatever Floats My Boat

Well, since it's now time to install my keel box, I started to worry about where to locate the thing.  I had calculated a center of buoyancy...but how accurate was my calculation.  I really didn't want to attach the keel only to find the boat sits way off it's lines.  So I figured the best thing to do was to go float my boat.  Sounds simple, but the problem was I didn't have an easy way to get the boat to the marina.  Also, it's been nasty windy, rainy weather here in the Northwest.  So even if we could use the boat lift, it would be tough getting any useful data with the boat bouncing around in the waves.  So yesterday, I decided the best thing to do was to bring  the water to the boat!  So I built myself a 28'x8'x1' test tank in the shop and filled it up with water.  Once word got out about what I was doing, I had no shortage of people show up to help me move the boat into the tank. (I found out later it was because they figured some sort of disaster would likely be part of the evening's activities and it was not to be misses!)  The floating of the boat went off without a hitch.  With no keel, it floats a bit nose high.  So I had the three guys go inside and simulate the weight of the keel.  By moving just over a foot forward of the center of the buoyancy, the boat floats level.  So with this info and a few more calculations, I will now be able to mount the keel with confidence!

Thanks to Chad, Dan, Dave, Erik, Kris, Michael, and Mitch for the use of your muscles and ballast.  Sorry there wasn't a flood or any other disasters to entertain you guys!  (and thanks to my wife Denise for taking the pictures so that people would actually believe I went sailing in the garage)

The toughest part of this little adventure was keeping my boys out of the tank today as I was filling it up.  They kept trying to convince me we need to leave this thing in the garage all winter long.  After we were done with Vertigo, they launched their El Toro dingy and paddle around for a while.  Too much fun!

Getting ready to build a mold

I've nearly finished fairing the keel bulb plug.  I think I may add a layer of glass just as reinforcement so the bondo "egg shell" doesn't crack when I push it into the concrete/mortar mix.  My plan is to make a 2 part mold divided into upper and lower parts.  The upper part will have the filling ports.  My goal is to make this a one piece bulb rather than having to bolt 2 halves together.

I am really fortunate to have the i550 blogs to look at.  Even though it's a different boat, it is still kind of similar and I am able to pick up a lot of little tips from seeing what those guys are doing.

Today I also got completely caught up on all my interior joint taping.  I also set the keel box on the floor of my boat and daydreamed about what kind of grid system I will use to integrate it into the boat structure. Not having a plan means ultimate freedom..but it also means lots of time just staring at stuff!

Building The Keel Box

 

Finally, the keel fin is faired and I'm very happy with how it turned out.  So next I built a keel box.  This will mount inside the boat on the floor and will, along with a grid structure, provide the support for the keel. 

Basically I just used the keel fin as a mold to make the keel box.  I did add some duct tape to make the finished box a bit bigger around the leading and trailing edge areas.  This will allow a bit of wiggle room to allow the keel to slide up and down more easily.  Next I wrapped the keel in plastic sheeting so that the keel box didn't become a permanent part of the keel.  Then I began wrapping the keel in Biaxial glass.  After 6 layers, I decided to let it set up so I could make sure this thing would slide off. 

It didn't.  As I mentioned before, I wrapped the keel with multiple layers of plastic sheeting before I began the glass layup.  Unfortunately, as I began sliding the keel box off, it slid a few inches and then layers of plastic began to bind up.  For over an hour, I tried all sorts of tricks and nothing worked.  Not even yelling at it.  Finally, I used a razor knife and sit it along the trailing edge.  It had enough flex that I was able to pop it free and slide it off.  I then pulled off the offending plastic and tape and slid it back on.  Perfect fit!  Snug but slides easily along the length of the keel fin.  I then left it on and added another 4 layers of uni-glass. So I ended up with a nice fitting keel box that is about an 1/8" thick solid glass.

Keel Blob

                        

 Continuing my work on the keel plug.  First I filled the skeleton frame with spray foam.  This was very cool as I ended up with something that looked like a giant grub larva..my boys were especially impressed.  Once the foam had cured, I used a hacksaw blade to  saw along the frames and bring the shape back to a bulb.  A little sanding, and now I'm filling it with bondo. 

I'm heading off to work until Monday.  Hopefully I can make some more progress next week!

The Origins Of A Bulb

Things have been quite busy with the kids, the holidays, and work..but I've been able to find a bit of time to plug along on the boat project now and then.  I've continued fairing the keel fin and almost have it done.  I thought I was almost done last week, but with each layer of fairing compound, I'm excited to find I'm exceeding my expectations but that it's still not quite perfect..so I grab my template an add another layer of compound.  With the shop being kind of cold from the weather, it takes a while for each layer of fairing compound to cure.

So since I've been waiting between fairing layers, I've been taping seams on the inside of the boat and am almost caught up.  I have run out of 6" fiberglass tape so it looks like a field trip to Fiberglass Supply in the near future.

One cold night as the snow was falling and I didn't feel like heading out to the shop, I figured I should start thinking about the keel bulb.  So I poured myself some wine and I did. And what I thought was, there's no reason for me to re-invent the wheel and try come up with my own bulb shape.  Since this project is sort of similar to the i550, I've decided to use the bulb shape someone already designed for that boat..with only ever so slight modification. I found the bulb lines on the i550 forum and downloaded them.  The only problem is that the i550 bulb weighs 180lbs and I'm thinking I need this thing to weigh around 550 lbs  So I grabbed my calculator, scratch paper, another glass of wine and began measuring, calculating stuff, and running ratios.  By some method which my memory is not exactly clear on, I arrived at the conclusion that by enlarging the i550's bulb dimensions by 45% this new bulb would weigh precisely 550lbs.  I know when I did the calculations I was pretty confident that they were sound, however, I will consider any weight between 475 and 600 lbs a complete success.  And if it's way off, I melt it down, build a new mold, and re-cast!

The first step is to build a plug which I will use to cast a female mold in plaster or concrete.  I am building the plug out of plywood and foam which I will fair (arg!! there's that word again!) and cover in fiberglass.

Laminated

Finally finished laminating the keel.  Ended up using E glass alternating between 12 ounce biaxial and 10 ounce unidirectional fabrics. for a total of 11 layers.  Did a simple hand layup using a brush, squeeges, and a laminate roller.  It's a nice thick layer of fiberglass.  From what I can tell, it's just over an 1/8 inch thick.  Which should be just about right.  It also seems quite smooth and true to the foil shape.  I'm sure I'll still have to do some fairing, but hopefully not too much.