This was much more of a pain that what it should have been, but in the end, I'm happy with the conversion. I was debating just buying the new Harken gear, but I enjoy modifying and fabricating things, so I just went ahead and used the original Seaways to see how well they work, and use the money on other parts of the boat. I probably did some things the hard way, so please only use this as a rough guide, and if you see an easier way of doing things, please post. Cost was around $25, this included the used single Seaway block found on Ebay, stainless hardware, and using the OEM cam cleat. Add $25+ for the Harken cam cleat upgrade, plus you will need to fabricate a bracket to hold the Harken cam cleat. The upside though is that the bracket can be made to bolt onto the outside of the triple block, so that you can adjust the angle without needing to pull apart the blocks.
First thing is to purchase a single Seaway block. I found mine on Ebay.
Drill off the heads of all of the rods holding the blocks together. Wrap your blocks in tape to keep them held together, there are lots of needle bearings and (6) small balls which can fall out. The rods can be stuck pretty good, so use a screwdriver, punch, or something of appropriate diameter to drive them out. It may be easier to pry off the side plates first.
Image shows the heads drilled completely off
Pry off the end plates.
Remove the rods.
End plates and rods removed.
Here is what the inside of the pulley looks like.
Notice there are three ball bearings around the perimeter of the sheave, they just drop into a shallow hole, and are loose. I believe they are only there as spacers so the sheave does not rub on the housing. These easily fall out and you will need a good flashlight and about 20 minutes of crawling around on your hands and knees if you want them back, don't ask me how I know. In the picture, I used duct tape to hold the pulleys together through this process.... don't do that. Use something that is easily removable, such as painters tape.
Keep the clevis pin in the center pulley, the outside pulley clevis pins can be removed.
Start to assemble the stack. I used end plates on the outside of the stack only. I started with a washer on the bolt, then slid on one of the outer pulleys, then the center ratchet pulley, then the opposite side outer pulley. You will need spacer washers in between each pulley. The quantity required will depend on if you are keeping side plates on the inner sides of the pulleys or not. You just want the pulleys spaced as close as possible, and parallel with each other, so adjust the washers accordingly.
For the center pulley with the ratchet & cleat, I chose to leave off the side plates. My idea was that the small screws on the adjuster plate now has nothing to screw into with the side plates missing, but they still drop into the holes which are left in the pulley housing. I though since the two outer pulleys are pulled tight to the inner pulley, that this would keep the adjuster screws secured and keep them from coming out. While this is true, it ended up being a bad idea as well. While assembling the center pulley, and trying to keep the pulley together, and keep the bottom adjuster bolt from falling out, it took many tries to finally get it without letting the pulley separate and send the little ball bearings flying out. Some temporary, cleverly placed masking tape may have avoided the whole issue, so if you choose to do it this way, I'd go that route. On a side note, if the angle of the cleat needs adjusted, you probably won't want to do it over the water.
Secure the bolts with nylock nuts, and grind the ends of the bolts down, removing any sharp edges.
Now you will need to get clever and figure out a way to add some sort of becket or tie off point for the line, which doesn't stick up too far, but also doesn't interfere with the ratchet operation. The simple idea that I had required using longer bolts for the cam cleat, then making two "L" brackets which will sit over the cam cleat bolts. The original roller becket & clevis pin from the seaway pulley is used on top of the "L" brackets. The "L" brackets may need to be bent inward slightly so that the clevis pin sticks out far enough to get the ringding attached. A tip for making a sharp bend in metal if you don't have access to a brake, is to clamp it in a vice, and tap repeatedly as close to the bend as possible. Eventually it will fold over the vice jaw and you can tap it straight down, creating a nice 90 degree bend.
Now assemble the remaining three single blocks for the uppers and that's it!
