by Scott Backholm
FORECAST: Today, SW Winds 5 to 10 kt, increasing to 10 to 15 kt in the late morning and afternoon. Waves 1 foot or less.
At about 2 p.m. you are wondering, why the heck did I bother listening to the forecast this morning? This is nothing like it!
It happens, we all know it. Regardless of the weather forecast if I’m heading anywhere around the Cape and Islands, I always assume that between the hours of 1 and 5 p.m. on a warm summer day the winds will blow out of the southwest and could easily reach about 25 knots. That is what I prepare for, and I’m usually right. I think the same thing happens off the south-facing beaches in Rhode Island and over into Long Island Sound. We all have special knowledge of our favorite destinations but at the same time we also know that a forecast is only a guess. A guess made by smart weather people, but still only a guess.
I was down in Montauk, New York in June for the annual Star Island Shark Tournament. I was in a friend’s 55-foot sportfisherman, a beautiful and safe boat for sure. Well, the weather was amazing, so on the first day we sent south to the canyons. When we were there, I noticed a couple of boats in the 22- to 25-foot range. Now, the weather was great, and these guys probably knew the area well, but I kept thinking, what if the weather worsened? What would they do? It’s definitely too far to run home quickly. So, what if your boating day is hit with sudden bad weather? What would you do?
Most severe weather, even severe weather that pops up fairly quick, can be avoided if you are paying attention. Keep a constant eye on the skies and horizons around you, feel for temperature changes, and of course wind changes. If caught in a squall, strong thunderstorm or some other type of heavy weather, there are a few decisions that you should make in a few minutes time that will decide the outcome.
If aware of the situation, the U.S. Coast Guard will usually issue a Special Marine Warning with text indicating that the NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A THUNDERSTORM and then the area, with a forecast of wind and conditions, and then recommendations such as to seek a safe harbor. If there is no notification from the National Weather Service (NWS) to the Coast Guard, then there will be no broadcast, so you are on your own. As I mentioned, there are some things to look for.
Strong sudden wind shifts, sharp changes in air temperature (up or down), dark skies, these are just a few. You are basically looking for anything out of the ordinary.
You cannot always tell how severe a thunderstorm is by looking at it. Sometimes we see ominous squall lines that look like the apocalypse coming. And then almost nothing happens. At other times it may not look so bad and turn out to be the end of the world in disguise. Or so it seems. One of the problems we have with thunderstorms is that they do not conform to any rules of behavior. Though they may appear to be moving in a certain direction, that is only from your perspective. From a larger perspective, they can be moving in more than one direction at once, as they always do along a frontal boundary.
You can observe this phenomenon on weather radar loops. Individual cells moving in one direction, but the whole system in another. Understanding this will give you a better chance of predicting movement. So, if you have radar, use it.
When storms pop up along frontal boundaries, the overall front is moving in one direction, while the storm is moving in another. The front may be moving east to west, but the storm cells are moving north to south along the front. My point here is that the apparent direction of movement may not be the true direction.
When you do get caught, your most immediate problems are loss of visibility, high winds and depending on your location, rapidly building seas. How you react and what you should do depends greatly on the size of your boat and the type of body of water you are on. No one can tell you precisely what the correct response is because every situation is different.
In a powerboat, you have an advantage that sailors do not. That is the ability to run away from weather of course but also to control your boat speed relative to wave speed along with the direction of travel. Controlling speed minimizes the effect a wave will have on a boat. Most people don’t want to slow down when conditions get rough, but that is an inescapable necessity.
Heading straight downwind, with waves heading exactly in the same direction as your boat is known as a following sea. When that direction is a number of degrees off a line drawn down the center of your boat, these are called quartering seas. Seas at an angle off the bow are said to be on the forward quarter. Seas parallel to the centerline are called beam seas. Seas directly on the boat are head seas.
Regardless of direction, it is necessary to control your boat speed and choose the one speed at which the boat becomes most responsive and controllable. Going too fast in a following sea means that you’ll fly off the top of one wave and bury the bow into the backside of the next. That’s not good, so we need to find the speed that yields the most comfortable ride while still keeping good control of the boat.
When following seas start to get really big, we have only two choices: either we slow down to the appropriate speed, or we have to change direction. If we put the seas on the aft quarter we can maintain a higher speed without stuffing the bow into the backside of a wave. On the other hand, we may not end up going in the direction we wish. (And you may have thought only sailboats engaged in tacking!) It then becomes a matter of whether our higher speed makes up for the extra distance we have to travel. Often times it does, making it advantageous to alter course 20 to 30 degrees. I want to reiterate how dangerous heavy following seas can be. It may be a better ride, initially, but a large wave off the stern or quarter could easily swamp the vessel. If you are forced to go with a following sea, maintain your situational awareness by looking behind you. You can gauge where they are coming from and if they are increasing, both things that may influence your decision to maintain or change your course.
Bottom line is have fun, but be prudent, and be aware of what’s going on around you.
The On The Water staff is made up of experienced anglers from across the Northeast who fish local waters year-round. The team brings firsthand, on-the-water experience and regional knowledge to coverage of Northeast fisheries, techniques, seasonal patterns, regulations, and conservation.