We were reminded last week of the importance of monitoring the weather prior to and during even the shortest of coastal passages. On a delivery trip from Middle Harbour to Botany Bay last week our dealer principal dodged the first Sydney ‘hurricane ‘ we can remember.We were monitoring this system’s progress on the Bureau of Meteorology site as it developed. It hit hardest at Kurnell with wind gusts of over 200 kmh. Matt and a new owner left our marina once the system had hit land and dissipated only to meet another system about 2 nautical miles off Kurnell. The brand new Jeanneau NC 11 they were in managed with aplomb all that mother nature threw at them including 50 + knot gusts and white out visibility.
It is timely that The Australian Maritime Safety Authority recently issued the following 5 ‘vital checks’ to make when planning a trip in your boat:
- Warnings current for your boating area
Warnings are the highest priority forecasts. They warn of potentially dangerous wind conditions expected during the next 24 hours. Winds of 26 knots or more indicate rough conditions for small boats.
|Type of warning||Average wind speeds indicated|
|Strong wind||26 to 33 knots|
|Gale||34 to 47 knots|
|Storm force||48 to 63 knots|
|Hurricane||64 knots or more|
- Weather conditions affecting safe navigation and comfort
Our coastal water forecasts provide information about conditions that may affect safe boating.
Take note of forecasts indicating reduced visibility from fog or rain, or risks to safety and comfort from thunderstorms, lightning or squall conditions.
Some forecasts will also include information on UV levels and the times of day to use sun protection.
- Wind conditions
To plan your trip for the best conditions, look for forecast trends in wind speeds and shifts in wind direction over the day. Forecast winds are average wind speeds, with gusts being up to 40 per cent stronger.
- Wave conditions
Also take note of swell and sea wave conditions and how your boat reacts to short, sharp sea waves against longer and flatter, but more powerful, swell waves. Forecast waves are average wave heights, and you should be prepared to experience maximum waves of twice the average heights.
Swell waves don’t enter enclosed waterways, but do have a dramatic effect on entrances to these areas.
Enclosed waterways are affected by sea waves — waves produced by the wind blowing across the region. A sea height of half a metre may create enough chop to swamp a small boat. For coastal waters, you need to consider swell and sea waves. Swell waves can be of considerable danger near reefs and breakwaters.
The combination of sea and swell heights indicates the wave conditions you may experience. But you can’t just add one to the other. For instance, a 2.5 metre swell and 2 metre seas results in wave conditions over 3.2 metres.
- Tide times
Knowing when high and low tide will occur is important for boats entering and exiting river entrances and crossing bars. The combination of an outgoing tidal flow or low tide can cause waves to become steeper than usual, making your boat difficult to navigate.