The Triton


Sea Science: Instruments crucial in plotting safe course


Sea Science: by Jordanna Sheermohamed

In a land-loving lifestyle, an increasing dependency on the incessant beeps and boops of technologically driven weather forecasts is a given. Text alerts of incoming rain and other weather notifications from hyper-local forecasting services using information likely crowd-sourced from everyday citizen scientists now afford most people “instant gratification” weather updates. 

Once land is left behind, however,  the ability to maintain the frequency of pings significantly drops, even when satellite service is in place. It becomes important to remember the basic foundations of the scientific method: observation and data collection.

Basic weather parameters can be measured with just a few tools, all considered useful to a seafaring adventure. Temperatures, pressure, wind and humidity values are some of the most important parts of weather data that are necessary to monitor on board.

Thermometers are usually the primary weather instrument, as temperatures and their trend measurements can indicate what to expect next, weather-wise. This can be relative to both air and ocean temperatures, which can often indicate where small scale-to-regional currents may be located.

A barometer

Downward, upward or insignificant pressure trends, measured by a barometer, help to indicate whether conditions are expected to further deteriorate, improve or remain unchanged, respectively. A barometer is probably the most important weather instrument to have on board, as its measurements provide more details about the atmosphere than any other instrument.  

General local conditions, as well as regional seasonal patterns, can help to anchor a forecast’s baseline. Pressure and winds are inversely related, meaning as one goes up the other goes down; consider how the lower the pressure of a hurricane, the stronger the winds.  Therefore, pressure measurements are a vital way of remaining safe during extended journeys in open waters, including the ability to plan ahead for safe harbors en route. 

Winds are the weather parameter that directly impacts both a yacht’s speed and quality of ride. Wind magnitude, which indicates both speed and direction, will determine local sea state conditions, as well as surface currents. In fact, the Beaufort Scale is a secondary, derived tool for wind that allows for the estimation of wind speed by the observed appearance of the water surface. From these crude estimations to mast-mounted anemometers, gauging the wind is a primary concern out on the water.

Humidity value, as it relates to dew and moisture in and around yachting exteriors, can be another important parameter, as this helps crew to prepare accordingly. Low-level wind speeds will also affect humidity values, aiding in both the relocation and mixing of air masses.  

Combining data from one or two tools can further increase the ability to make an even more accurate forecast.  After all, weather is ultimately all things temperature- and moisture-related. Where the heat and moisture go, the “action” follows.

Safety aside, both transit and leisure time are directly related to weather conditions on a yacht. The ability to plan ahead accordingly is critical in creating the ultimate experience for yacht guests,  as well as crew.

Jordanna Sheermohamed is president and lead meteorologist of Weather Forecast Solutions, a weather-forecasting firm (  Comments are welcome below.

Share This Post

About Jordanna Sheermohamed

Jordanna Sheermohamed is president and lead meteorologist of Weather Forecast Solutions, a private weather-forecasting company ( Comments are welcome at

View all posts by Jordanna Sheermohamed →

One thought on “Sea Science: Instruments crucial in plotting safe course

  1. Lucy Chabot Reed

    This photograph of a barograph is incorrectly labeled as a barometer.
    Barometers only capture one independent reading at a time whilst a barograph takes readings over the course of a week, which is much more helpful in predicting weather than a single reading.
    Laura Lastfogel
    Deck crew

Leave a comment

Your email address will not be published. Required fields are marked *

Please answer the question below to leave a comment. * Time limit is exhausted. Please reload CAPTCHA.

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Editor’s Picks

Recent yacht fires a warning: Know your insurance details

Recent yacht fires a warning: Know your insurance details

By Dorie Cox No one wants to burn through a $20 million loss like the 102-foot M/Y Polar Bear in a San Diego shipyard in 2014. The …

France, Italy change Med charter VAT laws

France, Italy change Med charter VAT laws

By Sara Ammannati and Camille Penquerch January was a month of significant changes for charter activity in the Mediterranean following …

Crew Eye: A successful catch and release, times three

Crew Eye: A successful catch and release, times three

Chef Chris Parthemore, left, and First Mate Tom Robertson at anchor just outside Gustavia, St. Barts, in February. “Tom got the first …

Triton networks with Lewis Marine

Triton networks with Lewis Marine

Nearly 250 yacht captains, crew and industry folks stopped by Triton Networking with Lewis Marine Supply last night to check out the …