There is a lot that can be said about training for a marathon swim that doesn’t need to be repeated here. In a way, a marathon in the Pacific Northwest is the same as a marathon swim anywhere. In a way, its very different.
Rather than plagiarize a bunch of stuff here, just go to the source.
The Santa Barbara Channel Swimming Association has a great preview of how to train for some major ocean swims.
You’ve mastered the easy stuff: you can swim for hours, you’ve figured out your nutrition, and you don’t chafe the way you once did. You’re ready for something harder.
First, you’ll notice it is colder in the Puget Sound then a lot of places. Even in the summer, the water will rarely break 60F. And in the Strait? You’ll be luck to see something above 50F.
There are no two ways about it, you need to be ready for the cold. It is doable, it really is, just don’t let it catch you off guard.
Take a look at the Cold Water FAQ page for some specific information on a different type of Seattle Freeze, or for a less local perspective, read through some of LoneSwimmer‘s extensive writing on the topic of cold water swimming.
The weather in the Greater Puget Sound basin isn’t too hard to figure out. The wind will be coming from one of two directions, north or south. A north wind means high pressure, clear skies, and warm air (for frigid air, if it is winter). A south wind typically brings more moderate temperatures and overcast skies with showers.
The north-south winds will either be with or against the north-south ebb and flow of currents. Opposing wind and tides will make for some choppy conditions.
Be prepared to swim into the wind and waves. And we aren’t talking big Pacific swells, just the little, annoying waves, the kind that break right where you are trying to breathe.
There are plenty of north and south facing beaches in the area to practice these conditions, and practice is highly recommended.
This is where your speed work will come in handy. With some luck, your pilot will guide you around all of the eddies and whirlpools in your way, but you’ll be better off knowing where to expect them. A flat calm day can turn wild in a moment where two currents meet, and being comfortable in rough water will pay off big if you can keep your head down and swim when that happens. Likewise, your swim may require a hard push to get into the finish if near-shore currents start to pick up.
Grab a nautical chart or pick up the phone and find someone to talk about the current. Getting the currents right is a must.