During the 2013 voyage, Empiricus carried a heavier load than she ever has (so far as I know, that is.) Usually her weight in the slings sits at 35000 pounds. This year, when hauling out in Cambridge Bay, the crane recorded her at 38000 pounds. That’s minus a crew of five, all their personal gear and 150 gallons of diesel fuel. I guestimate she sat at 40000 pounds wet when we left Nome.
Being a fairly narrow hull, she sits low in the water anyway, so the increase in cargo affected her waterline a bit. And although she sailed as beautifully as ever, she did squat a little.
I had been chasing a pesky leak for quite some time. But I just could not pin it down. I only got a wet bilge when underway. While sitting at the dock, no water would gather in the bilge.
This was perplexing to say the least and I spent a fair amount of time sealing through-hulls above and below the waterline, as well as replacing hoses and the like. The leak was always manageable. That is until the boat tipped the scales at those record weights and began moving forward…
I say moving forward, because after departing Nome, irritated with the 100 bilge strokes per shift we were faced with, I crawled down in the engine room. Now that I had crew that could handle the boat, mostly without my help, I could investigate the issue fully, while underway. So that’s just what I did.
Boy, was it nice to set after a problem while the boat sailed on, without fretting over the rigging and our heading. Having in the past mostly singlehanded Empiricus, my time had always been divided into small slices. So having a crew was a bit of an adaptation for me.
I crawled in the engine room with a flashlight. On top of stored parts and a bagged-up, very expensive composting head that did not work, I saw the leak for the first time
Just above the stern tube, a steady trickle of water was squirting up from the packing. I was confused because I had looked there before while anchored and at the dock. It was always fine.
Then I recalled that this area was always wet. I had assumed it was just wet from the bilge sloshing around.
Assumptions are bad. But we all assume many things without knowing. Assumptions are part of our process of elimination. It bites us the worst when a phenomenon beyond our knowledge is thrown into the mix.
Speaking of phenomena… as it turns out, as a boat moves through the water, a phenomenon occurs, where the waterline at the stern raises up. That is, a lobe of water rises near the stern and stays there – effectively acting as though your stern has sunk deeper than it does when motionless.
In our case, the rudder post stand pipe was very short – just inches above the waterline. This was done to accommodate the large steering gear that sat above it. So whenever we were underway, the water was continually forced against the rudderpost seal, causing the leak.
The seal itself was problematic, in that it was hard to see or reach. It was also old, homemade and warped. I tried resetting the tension but to no avail. It just kept leaking.
I painfully watched the miles tick by. Stroking the bilge along the way, awaiting a time to repair it.
Once we reached a calm anchorage on the North Slope, we moved all our fuel forward and I disassembled the packing.
My heart was in my throat as I exposed the top of the five-inch pipe that held the ocean out. I could reach down to the waterline easily with my finger. This made me nervous. Jason stood by with parts and supplies as I tried to repair the existing seal. We used rubber material and eventually some neoprene from an old survival suit. But the results were not stellar. By the end of working for hours in a cramped, dark lazarrette, we had only reduced the bilge strokes by half. Still too leaky for my taste. But secure enough to continue.
I was, however, relieved to have found the problem and my mind spun continually on a way to fix it.
Ultimately this weighed in on my decision to stop in Cambridge Bay. Some crew needed to get home. The ice was bad, and the bilge was leaking. Three strikes. It was time to slow it down. Explore more. Fret less.
Once we finally hauled out, I took some paper and measured the circumference of the rudder shaft, as well as the head space from the stern tube and the tube itself.
The paper went in a zip lock bag and flew home to Alaska with me. This winter I took to the shop where I work.
Having done a lot of brainstorming and figuring out only concepts, I decided to build a mock up of the steering system. That way I could solve the problem, real time, like a leaky stern tube simulator! This is how astronauts solve problems. And while we were in Southeast Alaska, Empiricus might as well have been on the moon. So with no access to her, I adapted this technique on a tiny scale.
My simulator in reality was a handful of scrap metal, some duct tape and cardboard. I tried my best to imagine being jammed in the lazarrette. But that is truly a unique experience.
Ultimately that mock up process led me to this solution.
I bought a 1 inch piece of hard neoprene rubber from Alaska Rubber Supply and drilled a hole in its center with a hole saw. This hole was just barely larger than the rudderpost itself. I then experimented with ways to shape it into a circular wedge. I tried a jigsaw and knife but the results were paltry.
My boss suggested using a bench grinder, which I then did. That was the ticket. Perfect shape, with a natural bevel that fills the gap between rudderpost and stern tube.
I sliced through one side, then pre drilled it for a set screw. I also did some testing, using Neoprene cement and decided to glue it, and screw it after slipping around the rudderpost.
Next I need to find a way to hold that plug in place.
So I took some stainless steel T-clamps and modified them. I cut one to pieces and used the pieces to extend the hoop and made arms to hold in the plug.
Having learned tig welding while building the handrails in 2012, I was ready for the task. The thin bands welded up nicely.
Next I had planned on ordering some neoprene cone style seals online. I called for a price quote. Over $200.00 for a cone shaped neoprene scrap and a bottle of glue was just silly. I thanked them kindly and declined the purchase.
I did however need some advice on neoprene. There was no one better to give that advice than STORMR. STORMR is a brand of neoprene clothing I have been testing for a couple of years. After asking some questions regarding strength and stretch, I ordered a couple of yards of high quality neoprene. Plenty to fix the problem and make more repairs in the future.
I then went to a local scuba shop and bought a can of neoprene cement. Made to repair dry suits – perfect.
Once the neoprene arrived and I had begun building the rubber plug, I used paper to cut my template for the cone shape.
My seal would completely encapsulate the rubber plug and retention cage, with enough slack left in its length, to easily stretch as the rudder post turns within the tube.
After carefully constructing a successful cone. I decided to go one step further and do some glue testing on the neoprene.
The cloth I ordered from STORMR had a cloth backing on it. Although it would glue, I got the best results when gluing the un-clothed sides together.
When building the cone this way, the final result would not be a smooth overlapping seam. But a lip that extends outward from the seal.
This little anticipated problem, became the solution to another one.
The other problem would be. How do I reach both hands in there, and properly overlap each half of the seal in such tight quarters. Without getting the glue contaminated. Or misaligning the seam?
But if the lip extended outwards. I could pinch the edges together easily with my fingers.
I decided on this method and cut the cone accordingly.
After looking it over, I was glad to realize that I could follow up behind the glue, with hand stitching, to seal it up permanently!
So there you have it. My version of a bomb proof rudder seal, for short stern tubes in hard to reach places in the middle of the Northwest Passage!
I would like to thank STORMR INC. (www.stormrusa.com) for help and advice regarding neoprene.
I would also like to thank Allen and Saunya Alloway of Wind and Water Charters http://www.wind-water.org for teaching me how to work with neoprene and a hundred other skills, years ago. Thanks guys!