Local Knowledge
By Eric Johnson

One of the key ingredients of successful racing is called "Local Knowledge". This is an understanding of how wind and current act and react in a particular location. In this article, we will be looking at the currents in Hempstead Harbor, which will be the site of the 1995 Women's North American Sunfish Championship this fall.

The first rule of thumb for tidal current is that it turns in the shallows first, but runs fastest in the deepest sections. So, if the tide is about to change in an unfavorable direction, stay deep until the deep section starts to move and then go shallow for the weaker current. The second rule of thumb is that the tide usually goes out faster than it comes in, so more attention needs to be paid on the ebb than on the flood. Hempstead Harbor can be broken into four distinct tidal zones: the inner harbor south of Sea Cliff Point, the middle harbor from Sea Cliff Point out to the jetty, the jetty area, and the outer harbor.

The Inner Harbor is the simplest area as it is a single flow condition. The tide flows in towards the power plant and ebbs out favoring the deeper water on the west side of the harbor. So, if we are sailing up to Mark "M" on a flooding tide, we would want to favor the west side going up to the mark and favor the shallower east side after rounding. This will give us the maximum gain sailing to the mark and the minimum hit while sailing away. If the current is ebbing, then we want to sail up the east side out of the main flow. After we round, we want to get into the deepest section to get the best push back to the North.

The Middle Harbor is more complex due to the convergence and divergence of tide going up into the creek. This only affects the east side of the harbor, but can be a factor during starts and finishes. During flood this current pulls water up the channel, away from the main flow across the mooring field. So if you started on the east end of the line heading up the harbor, you would notice that you seem to be making more leeway than usual and that the moored boats on you lee appear to come up faster than you expected. In this condition you would want to start on the west side of the line and favor the west side of the course. The evv pushes mainly down the channel and fans out across the mooring field. This flow can help you because you appear to make less leeway and can sneak along the mooring field and around Sea Cliff Point more easily. The conditions in the rest of the Middle Harbor are similar to those in the Inner Harbor.

The Jetty Area has the most complex currents in the harbor. The combination of the Jetty and the shallows off Mott Point form a funnel through which all the water must pass. Due to the increased depth to the east side, the area around the Jetty usually has the most current. During ebb, if you are heading out of the harbor, you want to travel just east of the middle of the gap in order to get the best push. But it always seems that you're trying to sail into the harbor in the worst part of the ebb. If you're sailing up the west side of the Harbor, you can rock hop around Mott Point to stay out of the tide. But, if you are on the east side, you can try for what I call the "Maramara Current". Ray Maramara was the top gun in the PHRF Fleet in his Ranger 23 "Water Music" and really studied the harbor carefully. In one Champagne Race, I had the lead over Ray and was looking to loose cover him on the way back from Weeks Point to make my time. Ray sailed in close to the shore while I held out about 150 yards. As we sailed up toward the Town Beach, Ray was sailing faster and faster. He tacked just off the beach and ran across "Taarna"'s bow with a 6 boat lengths' lead He ducked around the jetty and beat us by a minute corrected. After the race, Ray explained to me that he wasn't going faster. I was going slower by sailing in more current while he had picked up the counter current that flowed along the shore and the back of the jetty on the ebb tide. I had sailed the shorter course against the current while Ray had sailed a longer course with the current. During the flood tide this current isn't as pronounced on the south side of the jetty; but, ducking behind the jetty in a light northerly can keep you ahead of the competition until the real wind arrives or dies completely.

The Outer Harbor is similar to the Inner Harbor with the main flow running east and west in the Sound, and the minor flow coming in and out of the harbor. The flow out of the harbor favors the east side moving around Weeks Point and joining up with the main flow at Matinecock Point. The beginning of the ebb causes a southeasterly flow from Prospect Point towards Mott Point. This later reverses into a counter current as the ebb builds. Sailing into the harbor in the worst of the ebb favors either sailing up the west side of rock hopping along the east side. On the flood, the reverse is the way to go.

So let's try an example: Wind from the SSW, High Tide + 2 Hours, Course M,G,Y. With the current pushing the fleet away from the line, we try to be a little early and look for a clean fast mid-line start. Knowing that the current is pushing out of the creek, we hold the starboard tack up to Sea Cliff Point to gain the most ground early. A short port tack out to the the Point and get a good line up the harbor and then tack back to run up the east side out of the worst of the current. We allow a little extra for the current before we tack for M. After rounding M, we go northwest to get deep into the current and then turn to run down to G. From G, we aim the bow high of Y to get the best reaching angle and let the tide set us down toward Weeks Point. We make a tight rounding of Y and run into the shore to get out of the current as quickly as possible. A series of short port tacks and longer starboard tacks along the shore would keep us in the shallowest and slowest moving water until we can pick up the counter-current behind the jetty. A quick run out around the jetty and tack back into Glen Cove Yacht Club's mooring field will minimize exposure to the worst of the current. We sail up the east side until we can just lay the finish line, tack out and then tack in to get the gun!

It sounds so easy, doesn't it? But the wind is a much bigger and more complex factor to fast sailing. In our next article, we'll be looking at some of the elements that affect the wind in our harbor.