When you are travelling 40 or 50 nautical miles to reach the continental shelf, you need more than a promising weather forecast. Conditions determine whether you should leave the ramp, whether the ground will be fishable and whether you can return safely.

There is no perfect formula. The aim is to combine the available information, understand the risks and give yourself the best chance of a safe and productive trip.

What You Will Learn

• How to compare several forecasts and read the broader weather pattern
• Why wind direction, swell period and forecast changes matter offshore
• How current affects line angle, jig control and whether the ground is fishable
• How tides, moon phases and predicted bite windows can guide your timing
• How to plan fuel and communications for the whole offshore trip
• Why every trip needs practical Plan A, Plan B and Plan C options
• How to make the final decision to go, change the plan or stay home

Weather, current, fuel and communications all influence the final decision.

Safety Comes First

Before considering tides, moon phases or bite windows, decide whether the trip is safe. Deep-water fishing may take you beyond reliable phone and radio coverage, and the return conditions can be very different from the run out.

Start Watching the Weather Early

I begin watching the weather about ten days before a possible trip. Long-range forecasts are not reliable enough for a final decision, but they reveal developing patterns. As the trip approaches, I look for agreement between several sources, including MetVUW, Yr, Windy, Windfinder, WillyWeather, Seabreeze and MetEye.

My Forecasting Routine

• Ten days out - watch the broad pattern and the synoptic charts
• Five to seven days out - compare models and identify possible windows
• Two to three days out - examine wind, swell, storms and expected changes
• The evening before - make a provisional decision
• Launch morning - check every forecast again and compare it with the conditions at the ramp

Jim's Tip: Never rely on one forecast, particularly when travelling a long way offshore.

Cross-check several sources and study the synoptic pattern behind the forecast.

Wind and Swell

Wind direction can matter as much as wind speed. Ten to fifteen knots may be manageable from one direction but uncomfortable or unsafe from another.

Westerly Winds

I treat westerlies cautiously because they blow offshore where I fish. Conditions may look reasonable close to land while becoming much stronger farther out.

South-east Winds

A south-easterly is often my preferred direction. Our usual current runs from north to south, so a south-east wind can push against it and slow the drift.

Crosswind

When the wind crosses the current, the boat can move in one direction while the line is pulled in another. This makes jig control much harder.

Swell Period Matters

Do not look at swell height alone. A longer-period swell is usually more widely spaced. A short-period swell can be steep and uncomfortable even when its reported height looks manageable. I prefer a period of ten seconds or more. Below about eight seconds, conditions can become unpleasant.

Forecast Changes Can Arrive Early

On one trip, a strong southerly change was forecast for late afternoon. It arrived around midday while we were about 30 nautical miles from the ramp. The wind quickly increased to around 35 knots, and a return trip that normally took 90 minutes became a 150-minute slog home.

Current Decides Whether You Can Fish

Weather determines whether you can reach the ground safely. Current often determines whether you can fish it. Where I fish, the offshore current may range from about 0.5 to 3 knots. Once it rises much above 1.5 knots, jigging becomes increasingly difficult.

• The jig is pushed away from the boat
• Line angle increases
• The boat crosses the ground too quickly
• The jig may never reach the target area
• The risk of snagging increases

Check the Actual Ground

Current can change significantly across a short distance. I compare several forecasts, then check the location I actually intend to fish. BathyMaps can provide the GPS coordinates of the ground, while platforms with point forecasts or measurement tools can be used to examine the predicted current at that offshore position.

Forecasts are useful, but they are not always accurate. I have travelled offshore expecting little current and found close to 3 knots in 300 metres.

Compare models, pinpoint the GPS coordinates and check the forecast at the actual offshore mark.

Wind, Current and Undercurrent

Wind with current: The boat may move too quickly, passing over the ground before the jig reaches the bottom.

Wind against current: This can slow the drift and help keep the jig vertical. Under the right conditions, it can produce excellent fishing.

Wind across current: The boat, surface line and jig may all travel in different directions, making the presentation difficult to control.

Undercurrent: Surface drift does not always reveal what is happening deeper in the water.

On one seamount trip, a 900-gram jig was pulled almost horizontally within about 30 seconds. The ground was effectively unfishable.

Wind and current determine drift speed, line angle and whether the jig reaches the target.

When the Current Is Too Strong

• Move shallower
• Look for a current break
• Try another side of the structure
• Change technique or target species
• Explore different ground

Changing the plan is better than spending the day fighting impossible conditions.

Tides and Moon Phases

Fishing around tide changes is productive. From my experience, the period around low tide may be slightly better, but there is very little in it. Offshore current is also influenced by weather systems, swell and underwater structure, so the tide table never tells the complete story.

Several days of strong south to south-east wind can sometimes slow the usual current. Current also tends to be stronger around the full and new moons, which coincide with the larger spring tides.

My Preferred Moon Phases

My favourite period is the lead-up to the full moon. It often seems to produce the biggest fish. The new moon can also be excellent and may produce greater numbers, although the fish are often smaller. These are observations from my fishing, not guaranteed rules.

Bite Windows

I use Tides4Fishing and Fishing Times to check predicted bite periods. They are not guarantees, but they are worth watching. I have experienced trips where the fishing was completely shut down before switching on almost exactly at the predicted bite time.

The forecast is most useful when it helps you decide when to be on your best ground, properly positioned, rigged and ready. Look for a bite window that overlaps with a tide change, sunrise, sunset or a rapid pressure change.

Use moon phase and solunar periods to focus your effort, not to guarantee the result.

Sunrise and the First Drop

On one memorable trip, the bite window aligned with sunrise. We had travelled 45 nautical miles from the ramp so the jigs could be working at first light.

Do the miles, get the smiles. Forty-five nautical miles from the boat ramp to have our jigs working at sunrise.

Not long after the sunrise photograph, the big fish arrived.

The reward for the preparation, the early start and the long run offshore.

Pressure Changes and Darkness

A rapid drop in air pressure can trigger good fishing as a weather change approaches. Unfortunately, the same system may force you to leave. Never remain offshore simply because the fish have started biting.

I have also seen deep-water fishing shut down as soon as it becomes dark. It does not happen every time, but often enough that I consider daylight and sunset when planning a trip.

Fuel for the Whole Day

Do not calculate fuel using only the distance to the fishing ground and back. Allow for the outward run, searching, repeated drifts, moving between marks, the engine running throughout the day, the return journey and a genuine safety reserve.

Headwinds, larger seas and course changes increase fuel consumption. The boat may also be much heavier coming home. It would not be uncommon for us to return with well over 100 kilograms of fish. Add the crew, ice and equipment, and the extra load can affect fuel use.

I have run out of fuel before. It taught me to calculate fuel for the entire day, not just the distance travelled.

A successful day can add well over 100 kilograms to the boat. Allow for the extra load when calculating fuel for the return trip.

Communication Offshore

A marine radio is essential, but it should not be your only means of calling for help. Carry a registered EPIRB and a satellite-capable device such as a Garmin inReach, Bivy Stick or compatible phone. Tell someone where you are going, who is on board and when you expect to return.

Use several communication layers when travelling beyond reliable phone and radio coverage.

Always Have a Plan B

The main objective for this trip was deep jigging, but the boat was also carrying an electric outfit, two trolling outfits, a stickbaiting setup and a speed-jigging setup. If the current, weather or fish behaviour made deep jigging impractical, we still had other ways to use the day.

Plan A - Deep jigging: Fish the intended deep-water ground when the current and drift are manageable.

Plan B - Change technique: Try deep dropping with the electric reel or trolling for pelagics. When fishing beyond the shelf, it always pays to have a stickbait setup on board, just in case the Yellowfin turn up.

Plan C - Change area: Move shallower, troll between spots or speed jig in shallower water.

Prepare realistic alternatives before leaving the ramp.

My Order of Priorities

• Weather - Is it safe to travel and return?
• Current - Will the intended ground be fishable?
• Tide - When will the water movement change?
• Moon - How might it affect current and feeding?
• Bite window - When should we be on our best ground?

A perfect bite window means nothing if the trip is unsafe. A favourable moon means little if the current prevents the jig from reaching the bottom.

Final Offshore Trip Checklist

Complete the final check before launching, then repeat it before committing to the run offshore. Continue monitoring conditions, drift, line angle and fuel use throughout the day.

Weather, current, tide, moon, fuel, communications and alternative plans in one final check.

Final Takeaway

Successful deep jigging begins before the boat leaves the ramp. Weather determines whether you can travel safely. Current determines whether you can present a jig effectively. Tides, moon phase, pressure and bite windows may influence when the fish become active.

Use forecasts to build a plan, but expect the conditions to be different when you arrive. Carry enough fuel, maintain reliable communication and be prepared to change the plan.

FISH SMARTER. FISH DEEPER.