Big Finding On Leak

We may have found the source of the large amount of water that we ship under certain conditions when driving forward in rough sea.

At noon yesterday Arnold and I began the project to reach a definitive and final conclusion on whether or not Pachuca was shipping water from the bow section. I had been so confident of the fiberglass work that I had done in the chain locker during my stay in Honolulu that I had eliminated the possibility that this could still be a problem - an opinion bolstered by my leak-free passage in that gentle passage between Hawaii and Juan De Fuca.

However, the serious bilge pumping during the rough passages to San Francisco and San Diego revealed that there was still a problem. My shock discovery that the chain locker could fill to the top with water became another clue to be investigated. Arnold and I had eliminated the water tanks with food coloring water (Good news: The red tank went empty this morning so we'll be drinking green water for the next week.) and then eliminated the stuffing box as the problem. Still baffled I decided to eliminate the chain locker once and for all.

We cleared out the forecastle by shifting everything in the area to the cabin. Then we cleared the sail lockers by moving the sails to the deck, which was of great benefit to the sails because some of their bags were damp.

If you refer to the photographs of the sail lockers you will see two ridges running fore and aft, one above the other, on the hull side of the lockers. These are stringers, defined as "a longitudinal structural brace for strengthening the hull of a vessel". Their purpose is to stiffen the hull to keep it from flexing. The stringers have two characteristics that play a role in our leak quest: (1) Their upper edges form channels along which any water leaking down the inside of the hull can run from one part of the boat to the other, (2) They are hollow, filled with a foam-like material, to save weight. I dried whatever moisture there was on the stringers and at the bottom of the chain locker.

We then plugged up the drain holes at the bottom of the chain locker with paper and started to fill it with water. Arnold noted that the upper drain holes were blocked off and I remembered that when doing the fiberglass work in Hawaii I did not see a need for these upper holes since water would pass around the edges of the upper level that I had constructed and drain out of the bottom. Of course now that I know that the entire locker can fill up with water in a rough sea way I realize that these upper drains would be of great assistance in draining the upper half of the water in that section. (The external stainless steel deflection plates such as the one shown draining in the last photo are still in place in the upper section. I plan to re drill those drain holes at first opportunity, which will not be in San Diego.)

As the water level went up Arnold noticed that water was flowing from the lower bolt on the stem that holds the anchor protection plate. I could see no serious water passing through the chain lockers. We then filled the chain locker to the deck level and other than the water dripping from that bolt and some water passing through the upper starboard stringer and at the bottom of the starboard locker we saw nothing serious. Arnold played the hose all over the anchor winch and we found no leaks there. We then drained the chain locker with me thinking that things up front were pretty much OK, though we had made the interesting discovery that the small amount of water leaking into the port sail locker was coming from inside the lower stringer. Somehow water was finding its way into that hollow section and emerging at the rear of the sail locker.

Then Arnold decided to pump out the bilge.

To our amazement he pumped 43 strokes, then twenty-something, then ten-something. We exposed the bilge and it still had a serious amount of water in it, fresh and not salty. (Yes, one of the duties of the skipper is to regularly taste the bilge water.) Wow! This required more investigation. I dried off the bilge and we started to fill up the chain locker again.

We discovered that when the water was very close to the top of the chain locker water would begin to flow through a drain tube into the transducer section at the front of the bilge. This water was coming from the bottom of the starboard sail locker. We played with water levels and found the threshold which determined whether or not water would flow in. That threshold was a water level an inch or two from top of the chain locker, which was actually at or near the top of the sides of the chain locker due to the curvature of the deck. The bilge was totally exposed during this experiment and at the end we had a seriously full bilge. That innocent trickle of water dribbling into the bilge added up to serious water in only a few minutes. The water at the bottom of that starboard sail locker was not dribbling down from the stringers or the side of the hull. We think that it was emerging from inside the lower starboard stringer in the hard-to-see aft section below the anchor winch battery.

One possible explanation of how water finds its way from the anchor well to the lower stringers emerges from the construction of the bulkhead separating the chain locker from the forecastle. It is constructed of two sheets of marine ply laminated with epoxy. We know that no water is passing through that bulkhead into the forecastle. However, it is possible - indeed likely - that water is passing from the chain locker into the cavity between those sheets of ply board then dribbling down to the stringers below where it is somehow finding its way inside. This is conjecture because although I know about the double-wall construction I have no solid information on the construction and state of the inter wall stringer area. (The plans of this boat did not survive the chain of ownership.)

If our conclusion is correct we have explained the source the large amounts of sea water being shipped when driving through a rough seaway. The leaks seem to be through the hard-go-get-to edges where the vertical walls of the chain locker meet the deck. Note that the this section need not be filled to the top when beating to weather: the heel of the boat along with the pitching and rolling will ensure that sea water is regularly slopped up to the edge. This finding is good news for two reasons: (1) The problem does not represent a fatal danger to the boat (as long as we keep pumping), (2) The fix is relatively simple and inexpensive.

We have on a 3-part remedial plan: (1) Prepare a thick mix of epoxy resin and use it to generously seal the entire upper perimeter of the chain locker, (2) Seal the cover to the chain locker as best we can, (3) Reopen those upper level drains.

Measure 1 above will probably wait until we are in the Sea of Cortez. One reason is that we must allow that section to become bone dry before we treat it with epoxy. Another reason is that maintenance work is prohibited at this yacht club. I've got most of the required materials on hand. I'll make sure that we have enough resin, thickener for the job. I've got sufficient fiberglass matting if we require it. I'll get fresh disposable gloves. I still have the coverall "Zoot Suit" that I used in Hawaii. The job will not be pleasant since I will be hanging upside down and covering the only source of ventilation. I will wear a mask and work in spurts to allow the fumes to clear the area.

We will to do the second measure here in San Diego. Arnold says that there are sticky-backed strips of rubber seal available. The cover does not have to be sealed to the standard of a cabin hatch. It must just slow the ingress of water enough so that the drains are not overwhelmed.

The third measure is best done when on the hardstand. The holes must be drilled from the outside at the correct angle and with a steady hand. They must also be lined with epoxy and preferably plastic hosing, as I did the lower drains.

The first photos are of the starboard (with the black cables to the winch foot switch) and port sail lockers. Note the stringers.

The next two photos show the sails and ground tackle on deck. The bright red bag contains our 18 ft diameter sea anchor. It is amazing how much weight is carried in those sail lockers: two spare jibs, a staysail, a storm trysail, a storm jib, two spinnakers, and the sea anchor. In a partition of the port locker is a Danforth kedging anchor with chain and rope rode, along with some spare parts and equipment.

The swimming pool scene is of the chain locker being filled with water. The removable upper level normally rests on the upper stringers.

Finally, the port lower drain at work.,