Hi Mary,
I sailed one design monohulls for 25 years and won eight US National Championships and I know about this ooching and pumping.
Ooching has to do with accelerating the hull forward on the face of a wave to get the boat up to wave speed so that the boat can be carried along at wave speed as it continuously slides down the face of the wave. Here we go: The boat is sailing downwind at a speed slower than the waves as monohulls usually do. As the wave comes up behind the boat and the tramsom begins to rise, everyone on the boat leans well forward slowly. When the boat reaches its most bow down position on the face of the wave, everyone on the boat leans aft abruptly. This generates an instantaneous small acceleration to the boat hull. Sometimes it is just enough to get the boat up to wave speed and then the boat is carried along at wave speed sliding down the face of the wave. The boat is moving along at wave speed instead of slower than wave speed. The sailors on the boat have accelerated the boat by shifting their weight aft quickly and the boat has reached a speed where it is now carried along by the wave. There has been a momentum exchange between the poeple in the boat and the boat platform. The boat has been successfully "ooched"! It has been accelerated by a force other than the force of the wind in the sails.
Now let's look at pumping. Pumping is causing the sails to generate a forward force by rolling the boat from side to side. Here's how you can tack a Laser in light wind and gain on the competition. As the boat goes into the tack, heel the boat to leeward and let the sail out to a reaching position. As the boat reaches about 30 degrees of turning, heel the boat abruptly to windward and continue turning. This will cause the rig to chop through the air from one side to the other side increasing the relative wind velocity across the sail for a short period of time and generating an instantaneous forward sail thrust. This is pump number 1. Now as the boat completes 80 or so degrees of the tack, the boat is still heeled to leeward on the new tack from pump number 1. At this point the skipper rolls the boat back down to level and sheets the sail in for sailing to windward. This second rolling action again creats an instantaneous increase in relative wind speed across the sail which creats another forward sail thrust. The boat comes out of the tack going faster than when it went into the tack. These two instantaneous increases is sail force were generated by an increase in relative wind speed across the sail due to rocking/rolling the boat under the control of the skipper. This action can be done while tacking upwind or jibbing downwind. This action is sort of like paddling your boat upwind or downwind by using the rig/sails as your paddle.
Boy o boy, isn't Laser racing great; no wonder they put that boat in the Olympics.
Beach cats don't ooch because they sail faster downwind than the speed of the waves anyway. Also beach cats don't pump because they can't rock their boats and cause the rig to swing through the air sideways as the platform rolls. Our platforms are too stable in the roll direction. We can't do the roll thing.
Bill