A three-day offshore trip out of Venice, Grand Isle or Fourchon is the hardest thing you will ever ask a cooler to do: three days of Gulf sun on an open deck, a crew opening the drinks cooler every twenty minutes, and, if the trip goes right, a hundred pounds of tuna or snapper that has to be at 32°F when it reaches the dock. Here is how to plan it — the ice math, the two-cooler setup and the fish handling — and which GATR sizes to take.

Short version: it is a two-cooler job. A GATR 110 with Wheels for the fish, packed with a hundred-plus pounds of ice and kept shut. A GATR 45 for food and drinks, which is the one that gets opened all day. On a two-day trip or a smaller boat, the GATR 70 with Wheels takes the fish cooler's job. One enormous cooler for everything is the mistake that ends with warm fish on day three.

Why one cooler is the wrong plan

Every time a lid opens, the cold air falls out and Gulf air takes its place. On a three-day trip the drinks cooler opens forty times a day; the fish cooler should open a handful of times, when a fish goes in. Put them in the same box and the fish pays for every beer. Split them and the fish cooler behaves like a sealed box in the shade — which is the only way any cooler makes three days in August.

It is also cheaper. A GATR 110 plus a GATR 45 is $800 and about 160 quarts of insulated space you can position separately — the fish cooler in the shade of the console, the drinks where the crew is. There is no single cooler that does that.

The ice math for three days

Two rules cover it. For food and drinks: about two parts ice to one part contents by volume, and top up the gaps. For fish: about two pounds of ice per pound of fish, in a slurry of ice and seawater. Then add a margin for the sun, because a cooler on a deck is not a cooler in a garage.

GATR does not yet publish ice capacity in pounds. The figures above are estimates from each cooler's interior volume, using the same fill rate the national brands' published ice figures imply (roughly one pound of ice per quart of interior). Treat them as planning numbers, not a spec.

Worked example: a crew of four, three days, a realistic box of two yellowfin at 40 lb each plus a limit of snapper — call it 110 lb of fish. Two pounds of ice per pound of fish says 220 lb over the trip. A pre-chilled GATR 110 loaded with 110 lb of block ice and topped up from the drinks cooler's meltwater and a second run of ice on the morning of day two gets you there. If the boat has no way to restock, load the 110 full, keep it in the shade, open it only to add fish, and be honest about the size of fish you can keep cold: a hundred pounds of tuna is a lot of heat to pull out.

Which GATR for the fish

The internal length is the spec that matters for fish. A 30 in redfish or a 27 in snapper lies flat in either; a 45 in yellowfin does not lie flat in any consumer cooler and goes in bent, gutted, or in an insulated fish bag. Two dividers in the 110 let you keep snapper away from tuna and both away from the bait.

Both run on solid off-road wheels that stay put in the boat — the cooler is stabilized until you lift it from the opposite end — and both lids are textured to double as a casting platform. At 50 lb empty and well over 150 lb full, the 110 is a roll, not a carry: from the truck across the dock and onto the boat with a two-person lift at the gunwale.

The food-and-drinks cooler: GATR 45

Four people for three days is a lot of sandwiches and a lot of water. The GATR 45 holds 42 cans plus ice, fits in front of most consoles at 26.7 × 16.6 × 16.3 in, and is the cooler the crew is allowed to open. Pre-chill the drinks in a refrigerator before they go in so the ice is spent keeping them cold rather than making them cold, pack two to one, and let the meltwater stay until the cooler needs to be lighter. If there is deck space, an Egg 25 on day one keeps the 45 closed until dinner.

Handling the fish so the ice can do its job

• Bleed every fish the moment it is on deck — a cut at the gills or the tail, head down over the side for a minute. Bled fish chill faster and eat better.
• Into the slurry immediately. Ice plus a bucket of seawater makes a slush that pulls heat out of a fish far faster than dry ice does, and gets it to 32°F in minutes rather than an hour.
• Keep the drain closed while the slurry is working. Open it only to drain warm water before a repack.
• Layer: ice, fish, ice. A fish sitting on top of the pile is not cold; a fish buried in it is.
• Measure on the lid before it goes in — 0–26 in on the 70, 0–30 in on the 110 — and check the season and limits at wlf.louisiana.gov before you leave. Red snapper limits change mid-season.
• Open the fish cooler only to add fish. Every other question — how many, how big — has been answered by the ruler on the lid.
• At the dock: drain, rinse through the garden-hose plug, leave the lid cracked to dry, and check the gasket for scales and grit before the next trip.

What we will not tell you

We will not tell you the GATR 110 holds ice for a number of days. Nobody can, honestly: a cooler pre-chilled and packed with block ice in the shade of a console is a different machine from the same cooler half-full of cubed ice in the sun on the bow. What we can tell you is that a one-piece rotomolded shell with two to three inches of foam and a freezer-style gasket, kept shut, is what makes three days possible — and that the five things that decide it are in your hands, not ours. They are in the ice retention guide.

We will also not tell you a 70 or 110 is the cooler most people should own. For most trips it is the GATR 45, and the size guide says so. The 110 is the cooler you buy because you fish offshore, keep a hunting camp or feed a crew, and it earns its price on exactly those days.

Where to go from here

• The saltwater fishing guide covers what a cooler needs on a Gulf boat — hardware, feet, lid, ruler — and which GATR fits which boat.
• The size guide has every dimension side by side.
• The boat could use decking too — GATR Skn, cut in Thibodaux.

Frequently asked questions

What is the best cooler for a 3-day offshore fishing trip?

Two coolers, not one: a GATR 110 with Wheels for the fish (150 cans or 100 bottles plus ice; 31.6 in long inside; two dividers; off-road wheels) and a GATR 45 for food and drinks. On a two-day trip or a smaller boat, the GATR 70 with Wheels takes the fish cooler's job.

How much ice do I need for a 3-day fishing trip?

For fish, about two pounds of ice per pound of fish over the trip, in an ice-and-seawater slurry. For food and drinks, two parts ice to one part contents. For a crew of four expecting around 100 lb of fish, plan on 110–120 lb of block ice in the fish cooler at the dock plus 40–45 lb in the drinks cooler, and restock on day two if you can.

How many pounds of ice does a GATR 110 hold?

GATR has not published a pounds-of-ice figure. From the interior volume (31.6 × 14.2 × 14.8 in), plan on roughly 110–120 lb of bagged ice with the cooler otherwise empty. Treat that as a planning estimate.

Will a yellowfin tuna fit in a GATR 110?

A mid-size yellowfin, gutted and bent, yes — the interior is 31.6 in long. A 60 lb-plus fish will not lie flat in any consumer cooler; use an insulated fish bag for the big one and the 110 for everything else.

Should I use saltwater in the fish cooler?

Yes. A slurry of ice and seawater chills fish far faster than ice alone and holds them at about 32°F. Keep the drain closed while the slurry works and repack with fresh ice when it thins.

Why not one big cooler for fish, food and drinks?

Because the drinks cooler gets opened forty times a day and the fish cooler should open only when a fish goes in. Split them and the fish cooler stays sealed and cold; combine them and the fish pays for every lid-opening.

GATR 70 or 110 for offshore fishing?

The 110 for three days, tuna and a crew. The 70 for two days, a smaller boat, snapper and mid-size fish. Both have off-road wheels, a casting-platform lid and a lid ruler; the 110 adds 4 in of interior length, a second divider and about half again as much interior volume for $50.

How long will a GATR 110 keep fish cold?

Kept shut, pre-chilled and packed with block ice in a slurry, several days — long enough for a three-day trip. GATR does not publish a days figure because shade, fill level and lid-openings decide the result more than the cooler does.

Does the GATR 110 fit on a center console?

It is 38.3 × 19.2 × 19.6 in outside. It fits across the transom or in front of the console on most 24 ft-plus center consoles; measure the space first. The wheels keep it locked in place until you lift the far end.