What size chase boat do I need for a dive programme?

Between 12 and 16 metres is where most superyacht programmes settle. That is enough length to carry tanks in racks, weight belts, regulators and a compressor, and to absorb chop on the run back, while staying small enough to launch from a dedicated shadow vessel or follow the mothership without imposing on charter guests. The deck also has to leave room for two divers to kit up at the same time, so the working area matters as much as the overall length.

How much range should a diving chase boat have?

We brief 200 nautical miles at cruise as a working minimum. A reef worth visiting is often two hours from the anchorage, and the dive day runs from a 6am departure through two morning dives, a surface interval, an afternoon dive and the run home. That range usually means 1,500 to 2,500 litres of fuel with twin or triple outboards in the 1,200 to 1,800hp range, or twin diesel sterndrives where the programme operates in the Indian Ocean or South Pacific and outboard servicing is sparse.

What does the boat need on board to support nitrox and rebreathers?

Four things: an onboard high-pressure compressor such as a Bauer Mariner or equivalent, sized for the daily fill load; a nitrox membrane or partial-pressure blending station with O2 stored in a separate vented locker carrying the right flag-state sign-off; a dry, temperature-stable area for rebreather sorb; and 240V power for handset, scrubber, light and camera chargers. All of that has to be specified from the keel up. Compressor location is not a detail - we have seen 20m boats where it made conversation on the foredeck impossible.

What coding and crew qualifications does a dive chase boat need?

The skipper needs RYA Yachtmaster offshore as a baseline, with a PADI or BSAC divemaster as a minimum and ideally an instructor for charter operations. The boat itself is usually MCA Workboat-coded under the Workboat Code, or operated under the tender's classification if it is under 24m and stays inside the parent yacht's operating area. Coding sets passenger numbers, distance from a safe haven and life-saving appliance scope. Cat 2, at 60 miles from safe haven, is usually enough; Cat 0 unrestricted is overkill for almost every dive programme.

Which builders should be on the list for a dive-capable chase boat?

Ribco, Pascoe, Hodgdon, Tecnorib (Pirelli) and Wajer are the names that come up regularly for dive-specific or dive-tolerant chase boats. The choice turns on the parent yacht's geography, garage constraints, and whether diving is the primary brief or one of three or four jobs the boat shares. Where diving leads, we usually steer owners toward a purpose-built chase platform rather than a sport-tender derivative - if you are retrofitting tank racks, kitting benches and a low swim platform, you have bought the wrong hull.

Diving Chase Boats: Compressor, Range and Crew

A diving programme is the brief that exposes a chase boat's compromises faster than almost any other. The boat has to carry weight (cylinders, weights, rebreathers, compressor), it has to carry people (a divemaster, a few crew, six to ten divers in kit), and it has to do both in a sea state that's often borderline for the mothership's stern garage. Get the spec wrong and you end up using a SOLAS rescue tender as a dive boat, which works once and then stops working.

What the role actually demands

A dive-led chase boat is a working platform first. The deck has to swallow tanks in racks, regulators on hooks, weight belts on rails, and still leave room for two divers to kit up at the same time. Most superyacht programmes settle on something between 12 and 16 metres, which is enough to carry the kit and absorb chop on the run back, but small enough to launch from a dedicated shadow vessel or to follow the mothership without imposing on charter guests.

The four constants on every brief we've worked on:

A flat working deck aft with non-slip, fresh-water washdown, and recessed tank racks
A dedicated bench seat with stainless backrest for kitting up, ideally on both sides
A swim platform low enough that a diver in full kit can step in and out without a ladder gymnastic
A compressor and storage hold separated from the working deck, ventilated, with adequate sound attenuation

If the boat doesn't have those, you're retrofitting them. If you're retrofitting them, you've bought the wrong hull.

Powertrain and range

Diving rarely happens within a mile of the mothership. A reef worth visiting is often two hours away from the anchorage, sometimes more if the programme is moving between islands. The dive day is also long: a 6am departure, two morning dives, surface interval, an afternoon dive, then the run home. That puts a real number on range.

We brief 200 nautical miles at cruise as a working minimum. That usually means 1,500 to 2,500 litres of fuel and a twin or triple outboard package in the 1,200 to 1,800hp range, or twin diesel sterndrives if the programme operates in the Indian Ocean or the South Pacific where outboard servicing is sparse. Quad outboards on a 14m hull look impressive on a boat-show stand. They're also a maintenance bill that nobody reads carefully until the second season.

For programmes operating from a support vessel, the chase boat's autonomy matters less than its launch and recovery cycle. A boat that can be lifted in the swell at the end of a long day, with a divemaster who's been in the water four times, is a different specification problem.

Compressor, nitrox, rebreather support

Most serious dive programmes today run nitrox, and a meaningful minority run closed-circuit rebreathers. That means:

An onboard high-pressure compressor (Bauer Mariner or equivalent) sized for the daily fill load
A nitrox membrane or partial-pressure blending station, with O2 storage in a separate locker, vented, with the right flag-state sign-off
A rebreather sorb storage area kept dry and temperature stable
240V power for chargers (handsets, scrubbers, lights, cameras)

If the chase boat is being asked to handle all of this, it has to be specified for it from the keel up. Compressor noise alone can drive a poorly thought-through chase boat off the brief; we've seen 20m boats where the compressor location made guest conversation on the foredeck impossible.

Crew, certification and operating envelope

A dive chase boat is operated by qualified crew, which means RYA Yachtmaster offshore as a baseline for the skipper, a divemaster (PADI or BSAC) as a minimum, and ideally an instructor for charter operations. The boat itself is usually MCA Workboat-coded under the Workboat Code, or operated under the tender's classification if it falls under 24m and stays inside the parent yacht's operating area.

Coding determines passenger numbers, operating distance from a safe haven, and life-saving appliance scope. A boat coded Cat 2 (60 miles from safe haven) is usually enough; Cat 0 (unrestricted) is overkill for almost every dive programme.

Builders worth the brief

For dive-specific or dive-tolerant chase boats, the names that come up regularly are Ribco, Pascoe, Hodgdon, Tecnorib (Pirelli), and Wajer. The choice depends on the parent yacht's geography, garage constraints, and whether the dive load is the primary brief or one of three or four jobs the boat has to share. If diving is the primary brief, we usually steer owners toward a purpose-built chase platform rather than a sport-tender derivative.

If you're scoping a dive-capable chase boat now, start with the brief before the hull, not the other way round.