Friday, October 22, 2010

Autobailers- Part One

Keeping it simple?

Autobailer side view - open

Some time ago, Paul Elevstrom came up with a simple solution for removing the water that accumulates in the cockpit when sailing small boats in big wind and waves. He used the fundamental Bernoulli principle (low pressure created by moving fluids – you remember) to invent the autobailer. In Lasers, 420’s, and other small boats I have seen, the autobailers all have the same basic design. A chute that can open and close is mounted at the lowest point of the hull and depends on suction caused when the boat is moving rapidly forward to remove water from the boat. It has “a wedge shaped venturi that closes automatically if the boat grounds or hits an obstruction, and a flap that acts as a non return valve to minimise water coming in if the boat is stationary or moving too slowly for the device to work.” (Description from Wikipedia, with British spelling of minimize.) Mr. Elevstrom’s autobailers have been bailing small racing boats for a long time now.

But wait! Autobailers have also been letting significant amounts of water leak into small boats for a long time now. Maybe cutting a hole in the bottom of a boat to let the water out is not such a simple solution. Isn’t that how boats sink?

I think many of us have had love/hate relationships with autobailers over the years. Sometimes they seem to work, and sometimes they cause annoying leaks. My experience is that they work well when they are installed, maintained, and used properly, but when those things are done poorly, the system breaks down quickly and the water flows the wrong way, sometimes in copious amounts. I suspect Paul Evelstrom was very good at care and maintenance. I certainly try to be good about those things with my Laser, but don’t always live up to his or my own standard. However, many small boat owners don’t believe in maintenance. They hate autobailers.

Among those who abhor maintenance are all of the sailors on the high school sailing team I coach. They not only abhor maintenance, they are inclined to practice abject neglect or worse on all of their equipment. Fighting these instincts in upper-middle class American teenagers is a tilting at windmills kind of exercise. Apparently, it is one of my callings.

We have a fleet of twelve old 420’s, no maintenance person or budget, and our boats, which are shared with the town recreation department, are heavily used. Despite ever improving preventative maintenance (done mostly by me), things still break – frequently. Although problems run the gamut in older boats, the overwhelmingly most frequent failure is leaking, nay, hemorrhaging autobailers. These devices depend on two different gaskets and a silicone or 3M5200 seal - three opportunities for water infiltration. For two years now, our favorite solution has been to tape over bailers with a 4” wide, waterproof tape which obviously also eliminates any possible benefit from autobailers. For several reasons, this approach has had various degrees of success, but it seems the “coach, my boat leaks” complaints never stop.

In fairness to the kids, some of the boats had seriously flawed autobailers by the time we got them. On top of that, we launch from a beach. Raising the main and putting on the rudders while standing in the shallow water stirs up the bottom enough to create an insidious slurry cloud that exposes all underwater parts to as much sand as water. Sand on the sailors’ boots also gets deposited inside the boat when they hop in. Rubber gasketed autobailers are just no match for sand that can penetrate the smallest of crevices. I can’t imagine the perfection in care and maintenance required to keep a bailer opening freely and closing tightly in these conditions.

With all due respect and deference to Paul Elevstrom, autobailers demand a high level of care and maintenance that is just not possible for us (and many others I suspect). A device that uses simple mechanics and physics turns out to be not so simple when operated by teenagers in a sandy environment. For us, a hole in the bottom of the boat is just a leak.

We won’t miss having working autobailers. They really don’t work well in the 420 anyway until the boat is going fast. Our courses are always short and don’t offer long fast straight-aways where the self-bailers work best.

The solution for us is a bleach bottle bailer and no hole in the bottom of the boat. Since all our boats came with an autobailer, the problem became how to remove them and plug the holes (twelve times) with a minimum of cost and effort. Necessity being the mother of invention, we came up with a way.

I haven’t heard a leaking boat complaint in six weeks, so I’m cautiously optimistic we may have found a relatively simple and definitely cheap solution for the hole in our boats.

Part Two will attempt to explain and illustrate our approach.


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