“Krackafat.” If ever a dive site deserved an innuendo-laden name — and there are quite a few in Papua New Guinea — this is it.

You know you’re about to dive somewhere special when the already enthusiastic crew are like kids on Christmas morning. Digger is buzzing like he’s had four double espressos, with Josie giggling and bouncing through her predive briefing. Digger had a sneak preview when he dropped down to tie on the mooring line: “Looks amazin’ down there!” he says, grinning.

Briefing done, we stride off the waterlevel platform into balmy 87 degree F seas and fin into a gentle current. FeBrina is hanging off the back of an underwater seamount, moored to the top through a permanent pin some 45 feet down. As I look forward, I can already see why the dive guides are so excited. The far side of the top of the reef is covered by a silvery-black cloud. In 1,600-odd dives, I have never seen anything like it. Horse-eye jacks in the thousands, a giant swarm swaying gently back and forth, face into the current. The top and sides of the mount — created by the volcano whose crater forms nearby Witu Island — are an explosion of color. Countless crinoids, multiple magnificent anemones, delightful dendronephthya, and clumps of red whip coral adorn the reef. Several species of schooling fusiliers dart to and fro, yellow and white pyramid butterflyfish flutter by in the hundreds, and swarms of anthias loiter around the barrel sponges and black coral trees as a couple of gray reef sharks patrol in the distance. The viz is even better than the 90- to 100-foot conditions we’d had the day before in Kimbe Bay, probably 140-plus feet. It’s hard to judge with all the fish in the way.

It’s also hard to know what to take a picture of. The school of jacks is so big, I can barely get a fifth of it in and lighted. The closer I get, the larger the school. As I come to the current side of the reef, I descend deeper to try to get under the cloud, and three dogtooth tuna cruise below me. Hanging at 90 feet, I let the camera dangle, and I gape in wonder.

Sixty minutes later, back on the boat, I ask skipper Alan Raabe what the name means. He asks in his Australian brogue if I found the dive exciting — in a gender-specific sort of way. I must look nonplussed. “‘Krackafat,’ to get a hard-on, good old Aussie slang.”

Krackafat is one of a number of reefs around the Witu Islands, about eight hours’ north of Kimbe Bay, off the north coast of New Britain Island, in the Bismarck Sea. There is no commercial fishing in the area, and the locals fish from dugout canoes. The bottom of the ocean is several thousand feet deep, creating perfect conditions for a superb reef in a country full of them. I’d estimate that there are over 300 known dive sites in the country. I’ve dived around 100 of them and not found more than a half-dozen that weren’t a great dive; most I would rate between “excellent” and “Can I live down here please?” Krackafat is probably my favorite of them all.

The Witus are dived as part of FeBrina’s 10-night “Signature” itinerary from April to June and September to mid-November, along with Kimbe Bay and Fathers Reefs, together forming a triangular tour with an overnight steam between each area.

Kimbe Bay has 40 dive sites on its own, the Witus close to a dozen, and Fathers around the same. Kimbe Bay’s outer seamounts are pelagic fish magnets, and Fathers Reefs have yet more barracuda, tuna, batfish, sharks and possibly the world’s friendliest turtles at Jayne’s Gully, a few of whom seem to have formed a bond with Digger. Shaggy Ridge and its silvertip sharks are also at Fathers, and multiple sites are great for gray and whitetip reef shark action.

From January to March, rains fall on the north coast of New Britain, but the mountain range along the spine of the island keeps the south coast dry. FeBrina operates out of Rabaul for three months, steaming round to the south coast on nine-night trips. The south coast itinerary takes you diving in the Solomon Sea, just off the 29,988-foot New Britain Trench. Nutrients from the über-deep create a wonderland of rare and unusual critters as well as pelagics.

In March, the 12-night Rabaul to Milne Bay, and the subsequent Milne Bay to Rabaul, itinerary includes diving in the Milne Bay area, Tufi, the d’Entrecasteaux Islands of Normanby and Goodenough, and along the southern coastline of New Britain at Lindenhaven.

While the boat isn’t the most luxurious vessel by 21st-century standards, the individually air-conditioned cabins do the job, and FeBrina makes a great dive platform with ample room for camera equipment and battery charging. I’ve done four trips on it now and am itching to go back as FeBrina visits what I consider to be the most beautiful, unspoiled dive sites on the planet.

FIVE REASONS TO DIVE M/V FEBRINA

1) THE PEOPLE
New Guineans are the friendliest people on the planet, and their good humor is infectious. Local kids paddle out to the boat to sell produce and fish — and to look at the funny people with all the crazy gear on.

2) PHOTO OPS
The variety of subjects is almost unlimited, from schooling jacks and barracuda, turtles and sharks, to a plethora of macro subjects including rarities like Coleman’s pygmy seahorse.

3) THE GUIDES
Josie and Digger have been guiding here for decades and know where to find whatever you want to see. Digger also has an excellent eye for composition and is always willing to show you the optimal spot for a killer shot.

4) THE LOCATIONS
Whether you are diving the outer reefs of Kimbe Bay, Fathers Reefs or the Witus, you’ll be in the middle of nowhere, stunning volcanic silhouettes on the horizon, or even moored in an extinct crater. The south coast is close to local villages.

5) THE VARIETY
There are pinnacles, seamounts, black-sand dives, swim-throughs, arches, overhangs and passes, and four different itineraries from which to choose.

NEED TO KNOW

WHEN TO GO The seven-and eight-night itineraries run mid-June to early September, and mid-November to end of December. The 10-night signature itinerary runs April to mid-June and September to mid-November. The New Britain South Coast itinerary is offered in January and February, and the trans-Solomon Sea 12-night trips run in March.

TRAVELERS TIPS Fly from LA direct to Brisbane in 14.5 hours, change planes for a three-hour flight to Port Moresby, and then change again for the 90-minute flight to Hoskins. From the airport to the boat takes an hour. Divers get an extra 33-pound baggage allowance on top of the standard 33 pounds for domestic flights.

Good chocolate is hard to come by, as are the latest DVD releases. Take a few bars and some movies on a memory stick for the crew.

Using a PNG specialist like Best of PNG, it’s easy to combine a cruise with cultural land tours or resort diving at one of the five dive resorts elsewhere in the country.

DIVE CONDITIONS With temperatures between 83 and 88 degrees F, only a light wetsuit or skin is required. Visibility runs between 60 and 120 feet, and there are mild currents on pinnacles on rising and falling tides.

OPERATOR FeBrina has seven below-deck en-suite cabins with individual air conditioning, which house 12 divers. It’s not a luxury boat, but the crew provides five-star service.

PRICE TAG Prices per person double occupancy run from $3,720 for the eight-night South Coast itinerary to $5,640 for the 12-night Milne Bay to Rabaul run.