We are happy to introduce a new tool for SeaWeather's Fishing Planner that will give our clients the ability to measure distance from one latitude/longitude marker to another. This Distance Marker tool is available for our Angler’s Basic and Angler's Premium subscribers. This tool will be helpful for any situation, whether it being a short day trip from port or an overnight passage to a more offshore location. Anglers will be able to now determine how far away a prime fishing location will be, or whether a desired location is reachable by daylight.

To access this tool from the Fishing Planner, users select the "Options" drop-down tab from the top menu bar and select "Enable Markers for Distance Calculations." You then simply click on the map to place the first marker, and then click again to place a second marker. The distance between these two markers will then be displayed. A third marker may be placed to determine its distance from the second marker, and so on.

The Distance Marker can be over-layed on any of SeaWeather’s weather or fishing plots. This can be useful for many situations, including to determining a distance to a hotspot for a certain species of fish, for example.

Another update just implemented now allows anglers to pin locations with markers for fishing hotspots. Users can click and drag these markers to various locations on the chart. The user will then be able to save screenshot images to their computer or device and view these at a later time. This can be useful for evaluating weekly trends, such as sea surface temperature changes, so that one may further hone in the best location to aim for.

As always, we welcome any questions or feedback on this feature in a continuous effort to enhance the Fishing Planner product for our clients.-->

The Distance Marker Tool will allow anglers to better plan their fishing trips. Shown here is a distance calculation from Key West to the Dry Tortugas, over-layed with data for Blue Marlin.

All About Waves

By: Jeremy Davis, Operations Manager / Meteorologist

As every mariner knows, the effect of waves on a vessel can range widely. In protected waters, light winds can produce barely a ripple, while strong winds over open waters can produce large, short period dangerous seas. Knowing how waves form and their potential effects on your vessel can help to ensure a smooth transit. There are also quite a few terms involved with dealing with waves, and understanding them is helpful when interpreting our forecasts and recommendations.

How do waves form?

Waves are generated as the wind blows over a smooth ocean surface. As the wind speed increases, so too does the friction between the air and water, resulting in the formation of wind waves that are choppy and short in period.
Given enough distance (fetch) over the open water, and enough wind, the wind waves (wind driven seas) will continue to grow in height and become more organized.
Eventually, the wind driven seas will move away from the region of origination, become longer in period, and smoother in appearance, and become swells. Swells can affect areas far removed from their point of origination.
An example of this would be a hurricane moving well offshore the U.S. East Coast. Large swells are generated due to the high winds within the hurricane, that radiate out in all directions, eventually reaching the coastline hundreds of miles away.
These swells can cause significant beach erosion and dangerous rip currents, even though the hurricane is moving out to sea and is not a direct threat.
At any location, more than one wave "train" can exist. Swells that originated from different weather features can affect a location, as well as wind driven waves. This can result in a confused sea.

Anatomy of a wave

Wave heights are determined as the vertical distance between the trough (lowest point of the wave) to the crest (highest point of the wave).
Wavelength is the physical distance between the passage of a complete crest to crest passage of a wave.
The wave period is the time, in seconds between the passage of a complete wave. Short period waves often have wave periods of less than 6-7 seconds, while long period swells can reach periods of 15 seconds or greater. Usually, the longer period the wave, the easier it is to handle for vessels.
The wave direction is the direction that the wave is originating from – i.e. a Northeast (NE) wave at 6ft is a wave moving from the Northeast to the Southwest at 6ft in height.

How a wave height is determined

Wave heights, periods, and directions are commonly determined by visual inspection, unmanned buoys, or by remote sensing on polar orbiting satellites.
The most reliable measurements of wave heights are performed through unmanned buoys. These are deployed along much of the U.S. coastline and offshore, and are operated through various government agencies and research organizations.
Visual inspection of a wave height is less accurate, as it is not measured through scientific instruments and is based upon the observers’ perception and human error.

Variation in wave heights

Wave heights occur along a broad spectrum. This means that waves occur at varying heights in a set or train.
Research by Bretschneider (1964) shows that wave heights occur along a probability curve. From this chart, wave height is along the X axis, with the number of waves on the Y axis. Note that as wave height increases, the probability decreases.
The top 1/3 of all wave heights is referred to as significant wave height.
Note that the mean (average) wave height is less than the significant wave height, and would be 0.64 times the significant wave height. Also note that 1 out of every 10 waves will be 1.27 times the significant wave height. 1 out of every 100 waves will be 1.67 times the significant wave height.
The theoretical maximum wave height is equal to twice the significant wave height.
As an example, a forecast for a 20 foot significant wave height would have the following breakdown:

Mean wave height=12.8ft
1 out of 10 waves=25.4ft
1 out of 100 waves=33.4ft
Theoretical maximum=40.0 ft

The following figure by Bretschneider (1964) shows the distribution wave heights over a large spectrum.-->

Putting it all together

You can be rest assured that at Weather Routing we are constantly monitoring ship and buoy reports, combined with forecast models and our experiences to ensure that all steps are taken to avoid large waves. Knowing your vessel’s weather constraints helps us provide you with the best routing recommendation to keep you out of dangerous areas, or to minimize waves if they are unavoidable. In addition, note that although forecasts may call for a forecast range, there may be rare sets that exceed this by 1 ½ to 2 times as part of the natural distribution of waves. You should always be prepared for the potential for higher wave action, even in times when relatively low seas predominate.