Stanchion Tank Vents

stanch4.jpg (17739 bytes)We corrected a problem that had been worrying me about the boat while we were in New Zealand.  The vents for the water, diesel and holding tanks were on the sides of the hull at about the beam.  Though they were mounted high on the hull and with the stiffness of the boat it seemed that it might be OK but it worried me.  I was also concerned because a colleague told me at work cocktail party that it could be a problem.  Well I didn't get too worked up about it because it just wasn't the kind of information that I was ready for in that setting though the provider was well informed as he had raced on a IP35 to Bermuda across the Gulf Stream and they had had problems with water in the fuel.

stanch3.jpg (19382 bytes)The warning and my fears were confirmed on the trip from Palmerston to Niue when we got some water in the fuel in rough conditions.  Fortunately it was just a couple of tablespoons and it was easily caught by the water separator.  We were lucky but we resolved ourselves to do something about it.

In New Zealand we talked to Birch and Mason about the problem and they suggest we move the vents into the stanchions.  Hellen and I removed the stanchions over the water and diesel vents (who cares about the holding tank) and took the to Northern Machine to have them modified.stanch1.jpg (32754 bytes)

We discussed the design and agreed how it should work.  A tube with a outside diameter to match our vent hoses would be installed up into the stanchion almost to the lower lifeline hole.  A hole it then cut below the top of the tube in the stanchion wall and a cover is installed over the hole.  This allows for the tank to vent at a high rate of speed but makes it very difficult for water to get back up and over the top of the tube.  The bottom of the stanchion is sealed with a welded plate to prevent any overflow from running down the hole in the deck that passes the vent tube.   With the bottom sealed the overflow needs a way out and this is provided with a small hole in the base. 

stanch2.jpg (28740 bytes)We then drilled a hole in the deck and remounted the stanchions.  The vent hoses were connected to the bottom of the vent tubes.  We filled both water and fuel after installing our new vents and there was no drop in performance of the vents.  More important, we really stress tested the fuel vent on the sail from New Zealand to Fiji.   We had a rough trip and we were healing toward the fuel vent.  We actually buried our rail several times which is an accomplishment on an IP38.  We were often having waves boarding on the windward side.  We would have gotten a lot of saltwater in both the diesel and water tanks if we hadn't made the change.  We didn't get any water in our fuel and our fresh water remained fresh.  Another boat transiting with us with vents on the side got water in their fuel and destroyed their fuel pump and injectors as the motored into Savu Savu.  It was an expensive repair that had them waiting in Savu Savu for weeks for the parts.  We felt really fortunate that we had made this change because it could easily have been us but it would have happened in Minerva Reef!