Castoldi JT21

LOA0.0m
Beam0.00m
Top Speed0kn
Guests0
Draft0.00m
EnginesYanmar marine diesel
Propulsionjet
HullGRP
ClassCE-C

About this tender

Castoldi JT21 - what we know.

The Castoldi JT21 is the model that does most of the work in the lower-mid Castoldi range. At 6.30m length and 2.60m beam, twelve guests on the CE plate, single Yanmar 250 mHP diesel to a Castoldi Turbodrive 240 H.C., this is the build we recommend when a programme needs a real diesel waterjet tender on a hull where 7.1m or 7.5m simply will not stow.

The recently-launched JT21 N revision moves the platform onto a V8 diesel running 370 mHP through the higher-output Turbodrive 240 H.C.T., GPS-tested at 45 knots. That is a meaningful step from the standard JT21's 37-knot service speed and shifts this hull into chase-territory if the owner specs it accordingly. For tender duty, the standard 250 mHP package remains the right answer, simpler service, lower fuel burn, and twelve passengers on a hull that captains can put against the swim step single-handed.

Highlights

Built for the work.

The four details we'd point out first to a captain who hasn't seen one on the water yet.

01

Twelve guests on a 6.3m hull

CE Cat C plate for twelve passengers on a 6.30m by 2.60m hull. That is a working number for a primary owner tender on a 50-65m programme, with deck volume left over for fenders, a beach kit and a small toy load. Folding console and standard Castoldi tube package.

02

Yanmar 250 mHP standard, 370 mHP JT21 N option

Standard JT21 runs a 250 mHP Yanmar through a Turbodrive 240 H.C., quoted top speed 37 knots. The JT21 N revision steps to a V8 diesel at 370 mHP through the H.C.T. waterjet, GPS-tested at 45 knots. Two configurations on the same hull, two different missions.

03

155L fuel, real day range

155-litre tank gives the JT21 a working two-hour run at cruise, which puts it well inside the operational envelope for a typical Med shore programme. Diesel consumption stays predictable, which is what makes this hull such a practical fit for charter or busy private programmes.

Gallery

The full specification

Every number, sorted.

Dimensions

Length overall
6.30m
Beam
2.60m
Draft
0.50m
Dry weight
1,850kg
Year
2025

Performance

Top speed
37kn
Cruising speed
34kn

Power and Tanks

Engines
Yanmar marine diesel
Power
250hp ea.
Propulsion
jet
Fuel capacity
155L

Construction

Hull
grp
Classification
CE-C

Capacity and Pricing

Indicative price
EUR 232,700 ex VAT

Specifications, prices, availability, and performance figures are supplied for guidance only and remain subject to confirmation by the yard, seller, broker, survey, contract, and final specification.

Questions, answered

Before you enquire.

JT21 versus JT23, which one to specify?
Garage geometry and guest count. The JT23 is 7.1m and fourteen-guest, more deck volume and slightly more range. The JT21 is 6.3m and twelve-guest, smaller envelope and easier to stow on hulls in the 50-65m bracket. If the GA can take the JT23, that is usually the better tender, but the JT21 wins on smaller hulls and on programmes where stowage is the limiting constraint.
Should we go straight to the JT21 N for the V8?
Worth a hard look if the programme will use the extra speed. JT21 N adds roughly eight knots in service over the standard, with a meaningful uplift in cost and a slightly more involved service on the higher-output Turbodrive. For typical owner-tender duty we still default to the standard 250 mHP, the JT21 N comes into its own when the boat is doing chase-style duty as well as guest transfers.
Has the JT21 hull stayed consistent year to year?
The hull has been refined rather than redrawn. Castoldi run continuous improvement on the JT range, with engine and waterjet revisions pushing the platform forward without breaking the storage envelope. A 2019 JT21 and a 2025 JT21 will run on the same garage drawing, with detail changes on console layout, electronics and the Turbodrive specification.

The yard

Castoldi

Albairate, Italy

Castoldi is an Italian manufacturer headquartered in Albairate, in the Milan metropolitan area of Lombardy. The company has been developing waterjet propulsion since the early 1960s, with the first mass-produced Castoldi waterjet unit presented at the Genoa Boat Show in 1969. Today more than 40,000 Castoldi hydrojet units operate worldwide, across civilian, military, and commercial fleets.

The range we ask Castoldi for runs from compact garage-fit tenders at 4.3m right through to the flagship Jet Tender 34 at 10.5m - sixteen passengers, twin 440 hp diesels paired to twin Turbodrive waterjet units, and a certified top speed of 50 knots. Every model in between follows the same build logic: deep-V hulls hand-laid in Kevlar and vinylester resin, Castoldi's own Turbodrive waterjet drives manufactured in-house, and a package of practical details - retractable helms, self-bailing cockpits, and walkthrough deck layouts - that captains value on a working programme.

The propeller-free drivetrain is the defining feature of any Castoldi. No exposed rotating parts below the keel means safe operation around swimmers and watersport guests; zero draft restriction means beach landings and sand-bank crossings that a conventional-drive tender cannot attempt. SOLAS-certified rescue versions (JT 14 RB, JT 18 RB, JT 19 RB) sit alongside the standard tender line, so owners running a dual-purpose programme can specify a single platform. We'd put the mid-range JT 21 through JT 28 models alongside the main European jet-tender alternatives: the build quality is consistent, the proprietary waterjet technology is genuinely in-house, and the range breadth covers most mothership garage sizes without compromise.

Last call · Available

Enquire about the JT21.

Castoldi · Albairate, Italy

Indicative price fromPrices on request
LOA
6.3m
Beam
2.60m
Top Speed
37kn
Guests
12

Tell us about your yacht, your programme, and the missions JT21 needs to handle. We come back within 48 hours with a written assessment - fit for the brief, lead time, and trade-offs against alternatives in the same band.

Prefer to talk? +44 (0) 77180 88055 · other ways to reach us

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