How to Plan an Offshore Run with SST, Depth and Distance

Short version: a good offshore run is planned at the kitchen table, not invented at the dock. Find the break, confirm it sits on structure, measure the distance with the route tool, and leave with a target and a fuel plan instead of a hunch.

Why planning beats searching

Fuel is the most expensive thing on the boat, and searching burns it fast. The anglers who consistently fish well offshore do their homework first. They know where the edge is, what is under it, and how far it is before they ever start the engine. The goal of this post is a repeatable routine you can run the night before and again the morning of, so you leave the dock pointed at real water.

Step 1: Find the temperature break

Open the SST layer for your region and look for where the colors bunch up. Smooth, slowly changing color is uniform water. The places where the color shifts two or three degrees over a short distance are your breaks, and those edges are where bait and predators tend to stack up.

• Start with the composite view so cloud gaps are filled and the real edge reads as one line. More on why in composite vs single pass.
• Switch to a single pass when skies are clear and you want the freshest, sharpest snapshot of exactly where the edge is right now.
• If you are new to reading edges, start with how to read a temperature break.

Mark the break that looks best. You are not committed yet. You are collecting candidates.

Step 2: Lay color over the temperature

A temperature edge is stronger when a color edge sits on top of it. Open the chlorophyll layer and look for the green to blue seam, the line where productive green water meets clean blue water. Where that color seam overlaps your temperature break, you have a higher percentage spot than either edge alone. The compare tool lets you put temperature and color side by side so you can line them up. See chlorophyll charts explained for how to read the color.

Step 3: Check what is under the break

This is the step that separates a decent spot from a great one. A break over flat, deep water holds some fish. The same break sitting on the shelf edge, a canyon rim or a seamount usually holds more, because structure pushes cold, nutrient rich water up and feeds the food chain from below.

• Turn on depth contours and find the shelf break, often near the 100 fathom or 200 meter line.
• Use the depth readout to hover or drop a mark on your candidate spot and read the exact depth in fathoms and feet.
• Favor the candidates where the temperature edge, the color seam and real structure all line up. Our guide to shelf breaks, canyons and seamounts covers why structure matters.

Step 4: Measure the run with the route tool

Now turn your best candidate into a distance and a plan. Use the route and ruler tool to draw a line from your inlet or harbor out to the spot.

• Read the distance in nautical miles so you can estimate fuel and time at your cruising speed.
• Plan a route that works the edge once you arrive, not just a straight shot to a single point. A break is a line, so give yourself a troll or drift along it.
• Drop and name a waypoint on the spot. Each waypoint shows its position, the water temperature there and the depth, and it syncs to your account so it is on your phone at the dock.

Plan your fuel for the round trip plus a reserve, and always build in margin for weather and sea state. The chart helps you fish smart. It does not replace seamanship, a float plan, or official navigation tools.

Step 5: Check current, buoys and the forecast

Before you commit, sanity check the plan.

• Currents: ReelTemps doesn't draw currents, so check the free IOOS HF radar maps to see which way the water, and the edge, is drifting. A break that has been sliding offshore will likely keep sliding, so plan for where it will be, not only where it was.
• Buoys: check the nearest buoys for real in water temperature, wind and wave readings. Remember that satellite and in water readings can differ, so the buoys are your ground truth. See ground truth SST with buoys.
• Weather and sea state: this lives outside the app. Check your trusted marine forecast and make the go or no go call on conditions first, always.

Step 6: Re-check the morning of

Water moves overnight. The morning of the trip, pull the latest passes and confirm the break is still where you left it. Charts update throughout the day as new satellite passes arrive, so a quick morning look often shifts your waypoint a mile or two and saves you a wasted search once you are out there.

A quick checklist

Run this every trip:

1. Find the temperature break on the composite, confirm on a single pass. 2. Overlay chlorophyll and find where the color seam crosses the break. 3. Check depth and structure under the spot. 4. Measure the run in nautical miles and drop a named waypoint. 5. Check currents and buoys, and make the weather call. 6. Re-check the morning of and adjust.

You can run this whole routine for the Bay Area, Northern California, Southern California or any region on the charts. None of it guarantees fish. What it does is put you on real water with a real plan, so you spend your fuel fishing instead of hunting.

Not for navigation.