In general, multi-boat competitions are organized in a series of rounds, with the fastest boats in each heat qualifying for the next round. The losing boats from each heat may be given a second chance to qualify through a repechage. The World Rowing Championships offers multi-lane racing in heats, finals and repechages. At Henley Royal Regatta two crews compete side by side in each round, in a straightforward knock-out format, with no repechages.
First of all, if you're considering rowing, just do it. It is by far the most enjoyable and beneficial exercise I have ever tried. I've made huge strides with both cardio and muscle fitness with the WaterRower, and it's so enjoyable I look forward to exercising each day. Yes, it is more expensive than most other rowing machines, but when you compare it to a lot of other types of exercise equipment, it's actually pretty reasonable. When you also compare the exercise benefit you get, it's a bargain.
The next time this happens try being more aggressive in leaning into the wave, but more importantly, you get your down-hill oar out of the water early. You can push the up-hill oar into the water to stablize the boat and prevent rolling too far in that direction. The water will be pulling your boat and oar tip in opposite directions here, so you won’t get trapped like you did before with the down-hill oar.
The rowing machine itself is unlike any other on the market with its patented water filled flywheel. It is hard to exactly copy the action of a scull on the water, but the mechanics of the flywheel spinning in water comes in a close second on dry land. The fact that the water is 800 times denser than air means that there is no need for any extra resistance or dampening that you will find in normal air rowers. The faster you pull, the more resistance is generated giving it infinite variability. However, if you want to be able to practice rowing with a faster stroke, you will have to reduce the amount of water in the tank unlike an air rower where you just have to adjust the baffle.