Guide
Support Vessels buyer notes
About support vessels
A support vessel is a separate yacht that carries the tenders, toys, helicopters, submarines, and crew that no longer fit on the mothership. The category includes shadow vessels, helicopter support vessels, submarine support vessels, and expedition support yachts. Each is a different kind of answer to the same question: what do you do when the programme has outgrown the garage.
This page is the entry to the support-vessel library. The category sits above the superyacht chase boats overview on capability, range, and capital cost, and operates on a different model. Chase boats day-run from coastal bases. Support vessels reposition under their own keel across oceans, in convoy with the mothership.
What a support vessel actually is
A support vessel is a commercially classed yacht in its own right, usually 35 to 80 metres, with the deck area and lift capacity to carry equipment the mothership cannot. Unlike a chase boat, it is built and crewed for ocean transits. Unlike a tender, it never lives in a garage. The mothership and the support vessel travel as a pair, sometimes a day apart, more often within sight.
The four sub-categories that drive the spec:
- Shadow yachts, the general-purpose category, mostly converted offshore supply vessels with deck cranes and large open aft decks
- Helicopter support vessels, with a certified helideck, fuel storage, and an MRO arrangement to keep the airframe airworthy
- Submarine support vessels, with a launch and recovery system rated for the specific submersible, plus pilot accommodation and pressure-vessel servicing space
- Expedition support yachts, polar or remote-area capable, with ice class, extended fuel and provision storage, and crew accommodation for two-week deployments away from port
A few support vessels carry all four roles. Most carry one or two and hand the rest off to the mothership or to local providers.
Why a support vessel exists
A 60 to 90 metre yacht has finite garage volume. By the time the spec includes a 14m limousine, an 11m beach lander, two RIBs, three jet skis, and a watersports toy box, the garage is full. Add a helicopter and a submarine and you no longer have a yacht, you have a logistics problem. The support vessel is the answer.
There is a second answer, which is to scale up the mothership to 110m and absorb everything into one hull. Owners that go that route end up in a different cost band and a different berthing-availability conversation. The support-vessel route is usually cheaper to operate and far more flexible, because the support vessel can travel ahead, set up an anchorage, and have the toys ready when the guests arrive.
Sizes and capability
Most support vessels sit in three brackets.
- 35 to 50 metres. Compact, often single-mission. Either a heli platform with a small toy garage, or a sub-support boat with a minimal aft deck. Crew of 8 to 12. Range 4,000 to 6,000 nautical miles.
- 50 to 70 metres. The mainstream, multi-role bracket. The Damen Yacht Support series sits here, as do most converted offshore supply vessels (OSVs). Crew of 12 to 18. Range 5,000 to 8,000nm. Aft deck of 200 to 400 square metres.
- 70 to 90 metres. Genuine expedition platforms. Ice class options, full helideck, sub-handling crane, large workshop and engineering capacity. Crew of 16 to 28. Range 8,000nm and up.
The full reference and builder set is on shadow vessel builders and the comparison against the smaller chase asset is on support yacht vs chase boat.
Builders and the OSV pipeline
Half the support-vessel market is purpose-built. The other half is conversion, mostly of platform supply vessels (PSVs) and anchor handlers from the offshore oil and gas sector. The offshore market provides a steady supply of ten to twenty year old hulls with diesel-electric drivetrains, large open aft decks, and the mechanical credentials to take a yacht refit. The economics of conversion versus new-build favour conversion below 65m and tilt towards new-build above that.
The dedicated builder set is short:
- Damen Yachting (Netherlands), the Yacht Support 53 / 6911 / 7011 series, the segment leader by volume
- Astilleros Armon (Spain), conversion and new-build, mid-market
- Westport (USA), the Westport 164 platform, US-flag friendly
- Lurssen / Abeking & Rasmussen / Feadship, top-end custom support yachts, usually built as part of a paired contract with the mothership
The conversion houses include the same yards that handle commercial OSV work, with a yacht-finish subcontractor handling interior and topside finish.
Costs
Support vessels are commercial-class yachts and the cost structure shows it. Headline budget bands:
- 35 to 50m converted shadow: 8,000,000 to 25,000,000 EUR
- 50 to 70m new-build or major conversion: 25,000,000 to 70,000,000 EUR
- 70 to 90m purpose-built expedition: 70,000,000 EUR and up
Annual operating cost runs 8 to 12 percent of capital value, dominated by crew, fuel, and class survey cycles. The total programme cost of a yacht plus support vessel is typically 1.4 to 1.7 times the yacht alone, which is the number the asset gets benchmarked against.
Classification, flag, and the carriage question
Support vessels almost always run commercial flag. The aft-deck cargo, the helicopter fuel, the submarine pressure vessel, and the support-crew complement push the boat outside the private-yacht code envelope. Most support vessels run on REG Yacht Code Part A or one of the cargo-yacht codes (PYLC), with class to ABS, Lloyd's, RINA, or DNV. The carriage of dangerous goods (helicopter fuel, dive cylinders, lithium battery toys) is governed by the IMDG code and is a non-trivial piece of the spec conversation.
The owner's side of this is mostly about who carries the operating risk and who provides the crew. A good build manager will want this settled in writing before the keel is laid, not after the boat enters service.
Support vessel vs chase boat vs large tender
The decision between asset classes is mostly about distance and crewing.
| Asset | Range | Lives in garage | Own crew | Cost band |
|---|---|---|---|---|
| Large tender | Coastal | Yes | No | 1 to 5m EUR |
| Chase boat | Day-running, 200 to 600nm | No, marina or alongside | 1 to 4 | 1 to 15m EUR |
| Support vessel | Ocean, 4,000nm+ | No, separate yacht | 8 to 28 | 8 to 70m EUR |
The full breakdown sits on chase boat vs shadow vessel and support yacht vs chase boat.
Where we sit on this
Support vessels are not our core market. We broker tenders and chase boats, and we will say so to anyone who needs the larger asset. What we can do is help owners and project managers understand the boundary, so the wrong asset does not get bought to fill a brief that another asset would do better. If the programme is genuinely a tenders and chase boat problem, we will tell you. If it has tipped into shadow-yacht territory, we will tell you that too, and point you at the people who do the larger work.
For now, the relevant entries to read are shadow yachts, helicopter support vessels, submarine support vessels, expedition support yachts, and the shadow vessel builders reference. To go back up the hierarchy: chase boats, tenders, and the home page. If you want to talk it through, get in touch.