Oregon Dory - W.I.P.
We built or as the boats name implies, are building an 18' Oregon Dory named "W.I.P" or work in progress. Most of the work on the boat was done 3 years ago but once the motor got slapped on it substantial progress slowed to short bursts during the winter or at other times when I feel that a critical upgrade needs to be done. After all is it about building the boat or using the boat?
The most recent upgrade to the boat is adding the spray rails. In all actuality this is something I should have done before putting the motor on it but sometimes I really like learning how things work by experience (like torque steering however I'll discuss that some other time). Spray rails are necessary in order to break the laminar flow of water over the hull, which under certain circumstances can cause a boat to handle poorly, submarine, or even flip over. Running the dory without spray rails we found that in some cases the flow up the port side of the hull would definitely pull the boat down to that side to the point that, well let's just say it needs spray rails.
On deciding how to go about doing the spray rails I turned to Renn Tolman's book, "A Skiff for All Seasons". Renn calls for doing it in two layers of 3/4" stock cut with a 30 degree bevel at the top of the rail so I went down to the hardware store and picked out some clear pine and ripped them to the right dimensions. The stock I got was 8' long and I got enough to go 16', unfortunately I didn't get time to measure the boat before going to the hardware store so I was running off of my best guess that 16' would be enough. Turns out it was, but it didn't leave me room to scarf the pieces together. I decided on the starboard side that I would just screw and glue the first layer on and butt join the pieces together. I dry fit the parts together and then pulled them off to glue them on.
We've recently started stocking System Three's gel magic in the u-TAH cartridge so I figured this was a good chance to give it a spin. The u-TAH cartridge is a caulking gun cartridge that dispenses both sides of the epoxy at the right ratio, using a static mixer tip the epoxy comes out mixed and ready to go. I laid out the pieces and began to squirt away with the caulking gun. It was nice that the material came out mixed but I did find that I wanted it to come out faster and that it took quite a bit of effort to squeeze it out. Later I did notice that System Three recommends using a caulking gun that gives better mechanical advantage than a standard caulking gun. Personally if I was frequently using the product I would switch to a powered caulking gun.
After squirting a bead of glue down the boards and spreading the glue out to cover the whole surface I screwed them into place. I was a little dismayed to find that I did not get even squeeze out down the whole length of the boat. I also did not like the way the joint laid as it stood a little proud and uneven.
For the port side I decided to join the two 8' pieces to make one 16 foot piece and to use a different method to screw it to the hull. Also I decided to use System Three General Purpose epoxy with cotton flock as a filler in order to glue the boards down.
As I mentioned I did not have enough length in the material to make a scarf joint so I decided to use a hand plan to taper the wood at the joint and then use fiberglass cloth on each side of the joint to reinforce it. I put 2 layers of 6oz glass on the back and 4 layers on the front as that was the side that would be put under tension. I wet out the glass for the back and laid it on a piece of wax paper and then wet out the pieces in place on the front of the rail. I used some weights to brace the wood and keep it from moving while the resin cured. After it cured I used a sander to knock off the excess and make sure the surfaces were fair. This worked really well and took a curve with out unevenness. It was also much simpler than scarfing and wasted no wood.
I then dry fit the spray rail to the boat, this time using longer screws and only in areas where I could put backer blocks, this was much easier than using short screws that didn't get enough grip in the hull to hold.
This time I used System Three General Purpose resin mixed with cotton flock as a filler instead of using the Gel Magic. On the first rail with the Gel Magic I used about 6 oz, spreading this new mixture on by hand was much more messy than using the Gel Magic and probably took longer, additionally we used much more epoxy as I ended up mixing 12 oz of resin plus cotton flock. I was happy though that I got really even squeeze out.
The outer rail laminations went well, I stuck with Gel magic on the starboard side and the cotton flock mixture on the port side. I didn't join the stock but put it on in 3 pieces (in order to stagger the location of the joints) and cut the boards at 45 degree angles where they jointed. They went on well and for the most part really fair, I'll just need to smooth some of the joints slightly with a block plane.
I'll be finishing them off later this week, at least to the point that we can get out on the boat this weekend and go exploring the islands.
The most recent upgrade to the boat is adding the spray rails. In all actuality this is something I should have done before putting the motor on it but sometimes I really like learning how things work by experience (like torque steering however I'll discuss that some other time). Spray rails are necessary in order to break the laminar flow of water over the hull, which under certain circumstances can cause a boat to handle poorly, submarine, or even flip over. Running the dory without spray rails we found that in some cases the flow up the port side of the hull would definitely pull the boat down to that side to the point that, well let's just say it needs spray rails.
On deciding how to go about doing the spray rails I turned to Renn Tolman's book, "A Skiff for All Seasons". Renn calls for doing it in two layers of 3/4" stock cut with a 30 degree bevel at the top of the rail so I went down to the hardware store and picked out some clear pine and ripped them to the right dimensions. The stock I got was 8' long and I got enough to go 16', unfortunately I didn't get time to measure the boat before going to the hardware store so I was running off of my best guess that 16' would be enough. Turns out it was, but it didn't leave me room to scarf the pieces together. I decided on the starboard side that I would just screw and glue the first layer on and butt join the pieces together. I dry fit the parts together and then pulled them off to glue them on.
We've recently started stocking System Three's gel magic in the u-TAH cartridge so I figured this was a good chance to give it a spin. The u-TAH cartridge is a caulking gun cartridge that dispenses both sides of the epoxy at the right ratio, using a static mixer tip the epoxy comes out mixed and ready to go. I laid out the pieces and began to squirt away with the caulking gun. It was nice that the material came out mixed but I did find that I wanted it to come out faster and that it took quite a bit of effort to squeeze it out. Later I did notice that System Three recommends using a caulking gun that gives better mechanical advantage than a standard caulking gun. Personally if I was frequently using the product I would switch to a powered caulking gun.
After squirting a bead of glue down the boards and spreading the glue out to cover the whole surface I screwed them into place. I was a little dismayed to find that I did not get even squeeze out down the whole length of the boat. I also did not like the way the joint laid as it stood a little proud and uneven.
For the port side I decided to join the two 8' pieces to make one 16 foot piece and to use a different method to screw it to the hull. Also I decided to use System Three General Purpose epoxy with cotton flock as a filler in order to glue the boards down.
As I mentioned I did not have enough length in the material to make a scarf joint so I decided to use a hand plan to taper the wood at the joint and then use fiberglass cloth on each side of the joint to reinforce it. I put 2 layers of 6oz glass on the back and 4 layers on the front as that was the side that would be put under tension. I wet out the glass for the back and laid it on a piece of wax paper and then wet out the pieces in place on the front of the rail. I used some weights to brace the wood and keep it from moving while the resin cured. After it cured I used a sander to knock off the excess and make sure the surfaces were fair. This worked really well and took a curve with out unevenness. It was also much simpler than scarfing and wasted no wood.
I then dry fit the spray rail to the boat, this time using longer screws and only in areas where I could put backer blocks, this was much easier than using short screws that didn't get enough grip in the hull to hold.
This time I used System Three General Purpose resin mixed with cotton flock as a filler instead of using the Gel Magic. On the first rail with the Gel Magic I used about 6 oz, spreading this new mixture on by hand was much more messy than using the Gel Magic and probably took longer, additionally we used much more epoxy as I ended up mixing 12 oz of resin plus cotton flock. I was happy though that I got really even squeeze out.
The outer rail laminations went well, I stuck with Gel magic on the starboard side and the cotton flock mixture on the port side. I didn't join the stock but put it on in 3 pieces (in order to stagger the location of the joints) and cut the boards at 45 degree angles where they jointed. They went on well and for the most part really fair, I'll just need to smooth some of the joints slightly with a block plane.
I'll be finishing them off later this week, at least to the point that we can get out on the boat this weekend and go exploring the islands.
Labels: cotton flock, epoxy, gel magic, oregon dory, scarfing, spray rails, system three, tolman
posted by Matthew Weaver @ 10:59 AM
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