There is a passage ritual practiced by offshore sailors worldwide that costs almost nothing, requires about ten minutes to set up, and will change the way you provision. A cedar plug trailing 30 meters behind the boat catches fish. Mahi-mahi, wahoo, skipjack, yellowfin tuna — the lure goes in the water, the cleat takes the line, and you forget about it. Hours later, the line goes tight and you have dinner. Sometimes you have dinner for four days.
Fishing from a sailboat is nothing like sport fishing from a dedicated boat. You're not trolling at 10 knots on a diesel-powered platform with an outrigger and a fighting chair. You're doing 5.5 knots in the trades with a lure trailing off the stern cleat, waiting to see what finds it. The gear is simple almost to the point of being crude. The results, in the right waters, are spectacular.
The Rig: Simple and Effective
The standard offshore trolling rig for a cruising sailboat is not complicated. You want a #2 or #3 cedar plug — a short, dense wooden lure in blue-white or green-white — or a small Rapala in a mullet pattern. Either will work. The cedar plug has been catching mahi-mahi and tuna since the 1950s. It has not been improved upon.
Behind the lure: a short length of wire leader (6–12 inches of 40–60lb stainless wire, single-strand) to prevent bite-off from wahoo and the occasional barracuda. Above the wire, a snap swivel — this lets you change lures quickly and prevents line twist from the lure's action. Above the swivel: 30 meters of 80lb monofilament. This is heavy enough to handle a large fish hand-over-hand without cutting your palms and stiff enough that it won't foul easily when coiled on the deck or in a bucket.
The far end of the line ties to a stern cleat with a loop or a bowline. When a fish strikes, the cleat takes the load. You don't need a rod — though a rod and reel is unquestionably the better tool, and the difference becomes obvious the first time you have a large tuna on. But the hand-line setup has caught fish on every ocean passage by sailors who didn't want to deal with rods. It works.
Troll between 4 and 8 knots. Below 4 knots the lure sinks and loses its action; above 8 knots most fish can't catch it or won't bother. The sweet spot for most offshore passage speed is right in this range, which is one reason trolling and sailing passage-making fit together so naturally.
The Tuna Reality
Skipjack tuna — 2 to 4 kilograms — are manageable on a hand-line. Albacore in the 6 to 10 kilogram range are a genuine fight but doable for most crew. Yellowfin tuna above 20 kilograms on a hand-line are a different category of problem. The fish has tremendous endurance. It will run deep and stay there. It will come up, see the boat, and sound again. A 30-kilogram yellowfin on 30 meters of hand-line is a 15-to-20-minute fight at maximum exertion. Your hands will hurt. Your back will hurt. If you're solo or short-handed, you have a problem — you can't leave the helm, and you can't fight a large fish with one hand.
The honest advice: if you want to catch large tuna regularly, rig a rod. A 30 to 50lb class offshore trolling rod with a lever-drag reel rated for 80lb line gives you mechanical advantage the hand-line lacks. You can fight the fish properly, use the rod's flex to absorb runs, and reel in the line you've given. The hand-line setup is fine for mahi-mahi up to 10 kilograms and for skipjack. For serious tuna, get a reel.
That said: a 5-kilogram skipjack tuna on a hand-line in the Atlantic trade wind zone, landed cleanly, bled properly, and served as sashimi two hours later — this is a perfectly reasonable meal and a fine offshore experience. You don't need large fish to eat well.
Catch and Clean: The Protocol
Speed matters once you've brought the fish to the boat. The flesh quality of a tuna or mahi-mahi is determined largely by what happens in the first 60 seconds after it leaves the water.
Bleed first, always. A spike to the brain — aim just behind the eye, forward of the lateral line — kills the fish instantly and stops the adrenaline-heavy muscle activity that degrades flavor. Immediately after, cut through the gill arches on both sides. Hang the fish over the transom in the water, head down, for 5 minutes. The blood drains. The result is sashimi-quality tuna rather than the metallic, soft flesh that an unbled fish produces. The difference is significant enough that it's worth doing even if you're going to cook the fish.
Mahi-mahi are easier to clean than tuna. Score around the head behind the pectoral fins, run the knife down the dorsal line, and fillet the two sides off the spine. The skin peels away easily. A mahi-mahi of 4 kilograms will produce two generous fillets in about 30 minutes the first few times, faster once you have the technique. Tuna should be cleaned immediately and kept on ice or in a cold seawater slurry; the flesh continues to deteriorate in warm conditions regardless of bleeding.
Keep your cutting board, knife, and workspace clean. Rinse with seawater, not fresh. Fish guts over the side well downwind of where you're sailing — even offshore, a slick follows you and you don't want to be in it.
Gaffs vs. Nets: The Right Tool
The gaff debate is simple once you've decided whether you intend to keep the fish. A net is the tool for fish you might want to release or for smaller fish that don't justify the damage a gaff inflicts. A landing net for fish up to 5 kilograms is easy to handle, preserves the fish well, and allows you to unclip and revive a fish you don't want. For schooling skipjack or a mid-sized mahi, a net is the right choice.
A gaff — a hook on a pole — is the tool for larger fish you are definitely keeping. A 15-kilogram mahi at the transom, still strong, with the boat moving at 4 knots, needs a gaff. Aim for the head or the shoulder forward of the dorsal fin. Strike firmly and cleanly, then bring the fish aboard in one motion. A gaff used hesitantly is worse than no gaff — it wounds the fish and loses it. If you're going to gaff, commit.
Never gaff a fish you're going to release. The hook causes internal damage that gives the fish a poor survival rate. For catch-and-release, bring the fish to the transom, remove the hook with pliers, and let it go without removing it from the water.
Fish Species by Ocean Area
Atlantic trade route (Caribbean, Bermuda, Canaries): Mahi-mahi are abundant from roughly May through November and the most consistently caught offshore species for Atlantic cruising sailors. They school near weed lines, debris, and floating objects with genuine reliability. Wahoo appear most frequently near the Azores, the Canaries, and through the Caribbean — fast, aggressive, and extraordinarily good to eat, though they'll bite through mono without that wire leader. Tuna are present everywhere in the warm Atlantic but are most concentrated near productive upwelling areas. Flying fish jump across the deck at night throughout the trades — they're not worth eating (bony, dry, not much flavor), throw them back before dawn.
Sargassum weed patches deserve special attention. Offshore in the Atlantic, accumulated sargassum at convergence zones creates floating habitat that mahi-mahi use heavily. A patch of sargassum the size of a tennis court might have four or five large mahi holding under it. Approach slowly, drag the lure through the weed line, and slow to 4 knots or less. Strikes are often immediate.
Pacific passages: Mahi-mahi are common in the tropics. Wahoo appear throughout the Pacific but are particularly concentrated in the ITCZ and near islands. Skipjack tuna are everywhere. On longer passages toward the Marquesas, yellowfin tuna are a reliable catch and large fish are common.
Indian Ocean: Similar species to the Pacific tropics. The Arabian Sea and Bay of Bengal have dorado and tuna. The southern Indian Ocean passages toward South Africa tend toward cooler water and fewer tropical species, with albacore appearing at higher latitudes.
Regulations
In US territorial waters (within 12 nautical miles of the baseline) you need a valid federal fishing license, obtainable online for a modest fee. State waters have their own requirements. Offshore beyond the 12nm line, open ocean fishing is effectively unregulated at the federal level — no license required for recreational trolling.
Shark finning is prohibited globally under international law and is never acceptable. Be aware of protected species: Atlantic bluefin tuna have complex quota structures even for recreational fishing; billfish (marlin, sailfish) are catch-and-release only in most jurisdictions. The NOAA FishWatch website has current US species guidance. Check the regulations of any nation you're fishing near.
The good news is that trolling a cedar plug for mahi-mahi and skipjack in open ocean is about as uncomplicated a legal situation as exists in recreational fishing. No permits, no reporting, no restrictions — just a lure in the water and whatever finds it.
The Sashimi Moment
There is a specific experience that veteran offshore sailors describe in nearly identical terms: a yellowfin tuna caught at mid-morning, bled properly, cleaned below decks in a rolling seaway, sliced thin with a sharp knife, plated on a cutting board, and served with soy sauce and wasabi from the ship's stores while still 600 miles from the nearest land. No restaurant produces this meal. The combination of freshness that land-based dining cannot replicate, the physical context of an ocean passage, and the satisfaction of having caught the fish yourself creates something that outlasts the passage itself in memory.
It doesn't require a large fish. A 4-kilogram skipjack, properly bled and chilled, sliced in the afternoon for the evening watch change, is a fine meal. A 15-kilogram yellowfin produces enough sashimi-grade fish to feed a full crew twice. Either way, the ten minutes it took to set up the cedar plug and cleat the line to the stern will have been some of the best-returned effort of the passage.