 |
| The chain locker drain platform |
Having completed my installation of the mahogany anchor platform and all the hardware associated with it, I could now focus on the chain locker belowdecks. The water from any chain locker must drain somewhere. On many a sailboat, the water drains downward into the bilge. On some boats, it needs some assistance in getting there. In this posting and in the next one, I describe how I constructed a drain platform (essentially a funneling device), and how I plumbed this platform to conduct water to the main bilge on the aft end of
Oystercatcher, my Ericson 25.
On the Ericson 25, as I suggested, all water from the chain locker drains downward through the lockers underneath the V-berth. From there, the water runs into the forward bilge. This forward bilge is separated from the main bilge by 2500 pounds of lead ballast in the belly of the boat. Click on the picture below for a close-up view.
This forward bilge, although quite small, is divided into two parts by the centerboard trunk. Due to its size, it's common for this forward bilge to lack a bilge pump. If someone were to install a bilge pump there (which might not even be possible on account of its size), he would in fact need to install two of them, since this bilge consists of two different halves. In the pictures above and below I have indicated with a red line the path that the water follows as it makes its way from the chain locker to the forward bilge.
The picture below will also help us see more clearly what I'm talking about. In the foreground there is the chain locker and the three lockers underneath the V-berth. On the port side of the mast compression post and centerboard trunk is one half of the forward bilge. On the starboard side, inside the head, is the other half. This starboard side is of course not visible in this picture on account of the bulkhead.
In the event of an emergency, any excess water flowing into these two halves would, I suppose, flow over the top of the 2500 pounds of lead and ultimately make its way aft to the main bilge and thus the main bilge pumps. There is a gap of approximately one or two inches between the lead and the cabin sole. In the diagram below, the orange line represents the main bilge and the main bilge pumps.
In normal situations, when there is no catastrophic flooding, any water that makes its way into the forward bilge is not going to get pumped out. Instead, it's just going to sit there for a long time - that is, until someone gets tired of it sloshing around or tired of it stinking (or both) and decides to sponge it out. In the picture below, we see the port side forward bilge with all of the grounding cables leading to the grounding bolt for the copper grounding bar. Also we see a black PVC tube and a clear hose. The tube is a conduit for a transducer cable. The clear threaded hose is the hose that I would soon run from the chain locker to the main bilge, over the top of the lead, just beneath the cabin sole.
Now let's focus on the subject of this posting - my construction of the drain platform for the anchor locker. Below we see the finished product ready for installation. Okay, I'll just go ahead and say it right up front. Yes, this does resemble in some ways an protective cup worn by male athletes in some sports, but I believe we're all old enough to put all snickering aside. Aren't we?
At any rate . . . my idea for the construction of this platform came from a discussion that someone initiated on the Ericson forum. I believe it was an Ericson 27 owner. That boat, despite the fact that it does not have 2500 pounds of lead beneath the cabin sole, still apparently has the same forward bilge issues as the Ericson 25. This Ericson 27 owner said that he solved his forward bilge issue by installing a shelf or platform that prevented the water from the chain locker from ever getting out of the chain locker itself. As I recall, this owner installed a through-hull in the chain locker to allow the water to exit at that point.
This owner, also as I recall, had epoxied his platform permanently to the hull. I thought his approach to things was clever, but I did not like the permanence of his set-up, and I did not like the fact that he installed a through-hull as a solution for the draining of the water. The permanence of the set-up meant that he would have great difficulty accessing the nuts for the deck hardware above the chain locker. The through-hull seemed to me to be an invitation for bringing more water into the boat, especially when the weather was up. After all, the through-hull would only be about a foot or so above the waterline - at anchor, with no heeling.
I wanted to adopt his general approach, but make my platform removable and make my chain locker drain not directly overboard, but to the bilge, where all other water that happens to enter the boat is supposed to drain.
I began by making a mock-up with some left-over foam insulation. One goal was to make the platform steep enough to prevent water from sloshing abaft over the aft end of it.
Another goal was to leave enough room underneath the platform for me to inspect the hose that would lead downward towards the bilge. The cardboard mock-up made it easier for me to get the precise shape of this space.
I then used the cardboard to create the real piece out of 3/8 inch, exterior grade plywood.
While I was doing this, I was often checking to see how the location of this platform would work with the chain locker panel that I was in the process of modifying. The large hole in the panel allowed me to see both sides of the platform. That was good.
It took a lot longer than I ever anticipated to determine how exactly I would drain the water from this space. Ideally, I would have installed a flush-mounted through-hull with a built in drain. This, however, would have required me to bevel the plywood in an appropriate fashion. Having gone through this beveling process in the installation of new bronze through-hulls for this boat, I knew that this would not be an easy task, especially attempting to do this in plywood, which would be prone to splintering.
Ultimately, I decided upon an inexpensive mushroom-head through-hull from West Marine. This little through-hull fit well inside of a plastic screen that I found on the bargain rack at this same store. This screen, I believe, had been designed for a Forespar brand scoop strainer. I felt that this screen was necessary to help prevent any debris from falling into the through-hull and thus clogging it.
I situated the through-hull and the screen as far down as possible on the platform. The lower the better, of course.
I had to take into account the green grounding cable that led downward from the forward chainplate to the grounding bolt in the forward bilge.
From what I could tell, there would be plenty of room for the through-hull and the hose (and the hose clamps) in the small space beneath the platform. This space quickly tapered down to a hole not much bigger than the hose that would run through it.
The reference lines would let me know where I needed to glue the mahogany cleats that would support the platform.
Now it was time for me to install the through-hull and the screen in the platform.
There was a nut on the bottom side of the through-hull for securing it in place.
The screen ended up being about 1/4 inch from the bottom of the platform.
There was no way for me to work around the green grounding cable. Therefore, I notched the platform. My plan was to seal any cracks with butyl tape.
Now it was time for me to protect the platform by applying two coats of epoxy to each side. I needed to to the same thing to the two mahogany cleats that would support the platform. Never mind the square-shaped piece of mahogany. That was for a section of the rudder that I was repairing at this time. I've mentioned many times in many posts (and on the homepage of this blog for that matter) that I always had multiple, seemingly-unrelated projects going on at once.
Never mind the square-shaped piece of plywood. That was for the galvanic isolator that I was installing on the hull on the inside of the cockpit locker. See what I'm saying about multiple, seemingly unrelated projects?
While all of this was going on, I purchased a stainless steel screw-eye from the local hardware store. The chain locker for this boat never had any terminus for the making off of the bitter end of the anchor rode. This was yet another sign that the two previous owners of the boat had never cruised her and had never done any serious, long-term, repeated anchoring with her. Would anyone cruising this boat want to worry about losing the anchor and anchor rode every time he dropped the anchor?
To install this piece of hardware, I needed to drill a pilot hole in the wooden block that Ericson had glued to the hull some forty years earlier. I didn't want to drill too deeply into this block, for obvious reasons. Therefore, I taped my drill bit to indicate to me the proper depth of the hole for this screw-eye.
I drilled the hole above the area where I had earlier installed the trailer eye (bow eye). For more on this, see my article:
http://www.ericson25.com/2013/10/trailer-eye-bow-eye-installation.html
I chamfered the hole with a countersink bit. This would allow the butyl tape to form a gasket of sorts around the hole.
My dry-fit of the screw-eye indicated that all was well.
I then cleaned the area and the hardware with MEK. It's similar to acetone, but it evaporates at a slower rate.
I then wrapped butyl tape around the appropriate parts of the hardware. This was the good stuff that Maine Sail sells on his Compass Marine website. See the link to this website on the homepage of this blog.
This chain locker looked so screwy and weird because the previous owner painted it with some cheap paint at some time in the past. He did this apparently in an effort to prevent . . . of all things . . .
the deck from leaking. I discuss his numbskull work in my article on my repair of the deck core in the chain locker:
http://www.ericson25.com/2013/01/deck-core-repair-anchor-locker.html
After I had installed the screw-eye, I used the MEK to clean the area where I would install the mahogany cleats for the drain platform.
After I had cleaned this area, I sanded the specific areas where the cleats would be located. Then I cleaned the area again.
It took longer to epoxy-coat the trapezoidal drain platform than it did to epoxy-coat the mahogany cleats. The platform needed two coats on both sides. The cleats only received two coats on one side, since the bare side would receive epoxy during the glue-up.
Inside the boat, I wet-out the bare side of each piece of mahogany, and I wet out the appropriate areas of the hull. Then I thickened the left-over epoxy with colloidal silica. This thickened epoxy I applied to the hull, and soon afterward I pressed the mahogany into it. I used white Gorilla brand duct tape to hold the mahogany cleats in place.
Now I turned my attention to the platform itself. Again, pay no attention to the square-shaped plywood. It belonged to my galvanic isolator project.
First I installed the through-hull. Then I installed the screen. Note the gloss on this piece of plywood. I did not sand this epoxy-coated board, since I had no intention of painting it. The smooth, glossy surface would help to repel the water.
Now I needed to install this platform in the chain locker. While this task, on the surface, seemed quite simple, it actually took a fair amount of work, as it involved routing a hose from the chain locker through several bulkheads and other obstacles that lay between the chain locker and the main bilge in the galley area of the main salon. That work is the subject of my next posting.
This ends this posting on my work to create a drain platform for the chain locker of
Oystercatcher, my Ericson 25.
No comments:
Post a Comment