What’s a big wave? Is it the 100-foot wave from The Perfect Storm”? Could it be the waves from a TV show called Bering Sea Gold, when they tell us there’s a storm, and it looks like all of 12 knots of breeze and two-foot chop?
The answer is yes. Any wave that makes you feel that you and your boat are in danger is a big wave. All that matters is that the waves are challenging you, and you’re nervous about handling them safely. There are some basic rules that can help:
The classic example is the trip back home from Catalina Island. You left the mainland early on Saturday, and it was flat with no wind, so you zoomed over (zoom speed is relative – maybe six knots from the Yanmar in the sailboat, and 25 knots from the twin Volvos in the cruiser). You leave for home on Sunday afternoon, and there 32 knots of breeze pushing some healthy wind waves along with a big swell rolling down the channel, and you’ve got 26 to 45 miles to go with that on your beam or under your quarter.
You are relatively inexperienced, but you’ll probably make it. You’ll beat up the boat, and scare the pants off your crew and yourself in the process. The crew may never get on the boat again. Or, you are experienced, and you’ll make it. You’ll wear yourself and the crew out, and the boat won’t be real happy either.
If you are next to the helm on one of those days, and the driver is calm and under control, it’s amazing how much you can learn just watching and listening. Then when you trade places and you’ve got the helm, have a calm voice in your ear, coupled with the positive results, can help you learn a lot, and apply it at the same time. Then you gain the confidence to try it yourself.
Going into the waves, while often scarier, is easier on the boat and the driver when you do it right.
Don’t worry about your specific destination – as long as you’re making up distance to the mark (technically VMG – Velocity Made Good), you’re doing well. If you steer at an angle somewhere between 20 ⁰ and 45⁰ off the face of the wave, the boat is a lot more comfortable, and is actually faster than heading straight into the sea. You don’t get the big flying spray, and you don’t get the big pounding crash, either. And, you’ll be under control.
Not steering at your mark seems counter-intuitive, but any racing sailor can tell you that it works.
That’s nice, you’re thinking, but at some point I have to make up for that angle away from the harbor mouth. You’re right. You do. If you’re paying attention, you’ll find a periodic flatter spot between waves that will allow you to make the turn (tack) without wrestling the boat over a bigger wave.
Heading downhill requires more touch, and more attention to your helm. The basic design of most powerboat hulls has a broad, usually flat, surface for the following wave to push on, along with a more or less square corner (the quarter). This means that when that big wave comes at the stern, it lifts the stern while pushing on that flat surface. The combination of shapes and forces make the stern want to go to the side, and the boat wanting to turn parallel to the wave’s face, tilting away from the rising wave. This can make for some interesting or even dangerous moments. Sailboats do the same, but with a less exaggerated motion.
With some practice, you can learn to anticipate your boat’s tendencies, and start steering up the face and down the backs of oncoming waves, into the direction that swinging stern takes (It’s called “Yaw”) on following seas.
When steering off the wind, some of the math works for you. If the waves are moving at 13 knots, and you throttle back to about 13 knots, keeping the bow down enough to increase your waterline (hence control and comfort), you’ll find that steering the boat and managing the course is a great deal easier. The waves are coming at you a lot slower, and you have much more time to make your adjustments to steer a comfortable and productive course. With some practice, you’ll find yourself actually surfing the boat on the swell.
Take it easy. Think safe, learn well, practice and just slow down. Your boat, your back and your crew will be much happier.