This post is still under construction. I just did a trip with Hig involving a number of bay & headland crossings, and decided to summarize the basics I learned. Hig, who has MUCH more experience on this, has agreed to provide editorial & color commentary, and hopeful some cool pix.
What is it? Bay crossing, as I'm using it, is paddling across large saltwater bays (up to several miles). Headland crossing is paddling around exposed saltwater headlands. Traversing large lakes is similar but generally easier, so I'm focusing on the saltwater end.
What's it good for? Open water crossings let you do some otherwise arduous or impossible trips with relative ease. For instance, check out our blog post on the recent Kamishak Bay Trip.
Recommended Tools of the Trade:
- Reliable Packraft. There's really nothing to puncture you out in a big bay, but you definitely want a raft that won't spontaneously come apart under use.
PFD. I HIGHLY recommend this.
Paddle Lanyard. Again, highly recommended. [See lanyard building post: viewtopic.php?f=28&t=1057]
Optional: Compass, Map (topographic is best). [need varies by situation]
Optional: GPS w/ map software.
Your main hazard is exposure: you're in a relatively slow, wind-sensitive craft a long way from shore. You'll need to allow plenty of time to cross, factoring in tidal currents or wind drift, and err on the side of caution where winds are subject to rapid change or exposure is high.
Bay crossing requires awareness. Perhaps the most dangerous thing to do is just "put your head down and paddle." You want to notice if you're drifting in a current, so you can compensate for it, or see an incoming storm or fog bank far enough a way to tuck in towards shore.
The most acute risk is losing your boat or paddle. For that reason, we prefer to do crossings with a boat-to-paddle lanyard, about 4 ft. long. How it works: if you fall out, HOLD ONTO YOUR PADDLE. Your paddle connects you to your boat. The lanyard prevents winds or waves from moving your boat away from you. Climb back into the boat, keeping a secure connection to the paddle or lanyard at all times. This can be enhanced by having a wrist loop. NOTE: THIS IS A GREAT SAFETY TOOL IN OPEN WATER, BUT COULD BE VERY DANGEROUS ON RIVERS. Personally, I always do open water with a lanyard, and never do swift water / rivers with lanyard.
Paddling + Currents + Wind Push = Actual Route
That's your basic equation. Keeping track of your actual direction of travel (vs. the direction of paddling) will tell you your combined wind push + currents. Note that both wind and currents will frequently change over the course of a long crossing.
Parallax Bearing: Line up two objects, one near and one far away, at your destination (straight ahead) or straight behind you. (example: a distinctive tree on shore, and a distant mountain peak). If you drift off-line, they will move apart with respect to each other.
Parallax Speed: Using the same principle, you can sometimes judge your forward speed. If you look directly perpendicular to you line-of-travel and can see both shore and a distant feature (usually mountains) that is MUCH further away than shore, the rate at which the shoreline and the distant landscape move past each other is your approximate rate of travel.
Paddle Sighting: Hig can do this, I'm pretty bad at it still. It takes practice: Line you paddle up lengthwise with your destination, sighting along it. Holding the paddle motionless, look back along it quickly. The offset of where it's pointing behind you from you launch point (or another known point you've paddled straight out from, on your given leg) is your current+wind offset.
Compass Bearing: If you might lose visibility (fog, night), having a relatively current compass bearing to shore (factoring in wind + current offset) is valuable. The most realistic way to do this is very roughly: choose a bearing with lots of "wiggle room" (i.e., site on the middle of mile-long shore).
HIGH TECH NAV
GPS navigation is very helpful, but two key things to remember: One, not all maps in a GPS are up-to-date in remote areas. Two, a GPS can run out of batteries, fry out, or fall in the bay at an unfortunate moment.
TIDAL RIPS & CURRENTS: Tidal currents can be powerful, but are predictable. Before attempting long crossings, familiarize yourself with the local tidal regime. Expect high and low tides to be roughly 1 day + 1 hour aftfer the last major high or low. Long, narrow bays are likely to produce the most pronounced tidal currents. Tidal "rips" occur where changing water velocities can cause waves to stack in height, forming areas of taller waves in otherwise lower conditions. This rips are dangerous because they can surf or flip you. Fortunately, they don't jump up suddenly out of nowhere: keep a weather eye out, and you should be able to spot them.
Rips (and large eddies) often form around constricting terrain, like islands and narrow bay or river mouths.
WIND WAVES & FETCH: Wind waves are your typical "waves on the ocean." Your big concern on a crossing is if they get so big and steep they capsize you. Big waves are more time-and-energy consuming to paddle through, but not inherently dangerous. Breaking waves are the big concern.
"Fetch" is the distance-over-water wind has to build up the waves. Longer fetch @ a given windspeed = bigger waves.
Things that should really raise red flags:
- High-speed marine traffic, especially if driven by drunk people. Packrafts can't dodge well.
BIG ships. Large vessels are unlikely to see you, and can generate substantial wake.
Large current-to-shoreline-length ratios. I.E., a 1 mile lake crossing to a half-mile target shore isn't a big deal. A 1 mile saltwater crossing to a half-mile target shore in a narrow bay with a 4-knot tidal current could be really tough.
Major exposure. Examples: Exposure to substantial fetch (miles) w/ unstable or windy weather; a large bay open to the ocean with downvalley/offshore breezes.
Long crossings: Just plain long... this should be pretty intuitive.
Ice Floes: dicey, dicey, dicey. Know what you're doing before attempting anything like this - and reading Erin McKittrick's Icy Bay chapter in A Long Trek Home is recommended. It came close to a "death scenario."