53 MJM 2021 Boat for Sale

Ci Sea

ASKING PRICE: $1,800,000 Watch Price

Vero Beach, FL

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Last updated Feb 11, 2026

Ci Sea Boat | 53' MJM 2021

CI SEA is a late model 2021 MJM 53z, designed by Doug Zurn and proudly built by Boston Boatworks. The 53z is the Downeast inspired flagship of the MJM line and features expansive single-level entertainment spaces between the pilothouse and aft decks, luxury private accommodations for four, impeccable engineering and construction quality; and truly impressive performance - all key attributes for the discriminating buyer.

The current owners acquired CI SEA in 2022 when almost new, and they have spared absolutely no expense in maintaining and updating this impressive yacht. Recent upgrades include new updated Mercury quad outboards with extended warranties, all new Garmin nav electronics, canvas, fabrics throughout, aft deck teak sole, deck non-skid and much, much more as noted herein. Without a doubt, one will be duly impressed with her condition and extensive features upon inspection.

Denison Yachting is pleased to assist you in the purchase of this vessel. This boat is centrally listed by Wellington Yacht Partners. It is offered as a convenience by this broker/dealer to its clients and is not intended to convey direct representation of a particular vessel

Denison Yacht Sales offers the details of this yacht in good faith but cannot guarantee or warrant the accuracy of this information nor warrant the condition of this boat for sale. A yacht buyer should instruct his yacht broker, or his boat surveyors, to investigate such details as the buyer desires validated. This yacht for sale is offered subject to prior sale, price change, or withdrawal without notice. This boat may be listed with another yacht broker.

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Ci Sea HIGHLIGHTS

Yacht Details: 53' MJM 2021
Location: Vero Beach, FL
Engines: 4 x 400.00hp (Gas/Petrol)
Last Updated: Feb 11, 2026
Asking Price: $1,800,000
Maximum Speed: 50 MPH
Max Draft: 3' 0''

Ci Sea additional information

Specifications

Cruising Speed: 40 MPH
Maximum Speed: 50 MPH
Beam: 15' 0''
Hull Material: Composite
Max Draft: 3' 0''
Cabins: 2
Heads: 2

Pilothouse And Aft Cockpit

The spacious pilothouse is the primary operating and entertainment space – fully enclosed for efficient climate control and quiet running underway. The opening windshields, side windows and rear door and window provide a complete outdoor feel when desired. There is multiple seating including helm and passenger seats, U-shaped seating with table to starboard, and a full-length settee to port.

The Pilothouse leads aft on one level to the cockpit area that features a fixed settee, and two additional matching movable seats surrounding a gloss varnish teak table. Access to the dock is easy with side entry doors each side, and transom doors leading down to the swim platform each side.

Additional details:

Optional stainless Stidd 500, wide passenger and double wide piloting seats
Optional helm and co-pilot dash and countertops in gloss finished teak with flush-mounted electronics
Optional aft sliding glass door with fixed aft windows in polished stainless frame
Optional electric powered drop-down aft starboard window
(3) Full opening electric windshields
Windshield wipers and washers
Sliding safety glass three-part side windows with tinted treatment (2024)
Drop-down Sunbrella privacy/sunshades side windows
24" Edson destroyer wheel with varnished teak rim
Footrests at each pedestal seat
Teak pilothouse expandable table on electric telescoping stainless pedestal
Pilothouse settees with blue Ultraleather-covered memory-foam bottom cushions, converting to double and single when needed
Second set of new unused white UltraLeather cushions in storage
Clear Awlcraft finished teak storage drawers, each side with locks
Large pilothouse settee lockers each side with mesh organizer bags for cords, hoses, bikes, hard luggage, dinghy, golf clubs etc.
Lockable companionway with safety latch

Piloting & Navigation

All new 2024:

(2) Garmin 8616 16-inch chart plotters at helm
(1) Garmin 8612 12-inch chart plotter at co-pilot station
Garmin GMR Fantom 24 radar
(2) Garmin GMI 20 instrument displays
Garmin Sirius XM weather antenna
Garmin Nmea 2000T
Garmin rear view camera
Starlink satellite system

Additional details:

Raymarine Ray 218 VHF
Raymarine AIS 650 tracking system
Mercury VesselView MFD controller, joystick docking, Skyhook station hold and Autopilot
320,000 Candela LED articulating search light (bow rail mounted)
Kahlenberg compressed air horn with auto fog/anchor signal
Ritchie compass
FLIR M232 infrared camera on pedestal with mast light on hinged mounting plate

Entertainment

Fusion MS-AV755 stereo with bass woofer, (4) pairs of speakers and Sirius radio
Pilothouse optional drop-down 42” smart TV over companionway
Forward cabin 24” smart TV
Guest cabin 31” smart TV
KVH TV3 satellite direct TV receiver dome on pedestal with radar and nav light
Glomex TV antenna

Electrical

Custom backlit electrical panel with 12V DC breakers and 240/110V AC breakers and digital DC and AC monitors conveniently located close to companionway
Westerbeke 9 kW genset - 505 hours, serviced Dec 2025
110V AC system w/Victron Energy Shore power system with 65' white 50-Amp cord and Cable Master/Glendenning with remote control (2024)
Batteries: (3) Group 8D AGM - 245Ah house batteries, (1) Group 31, 105Ah/800CCA per engine (new 2022)
150 amp alternators on each engine
Blue Seas automatic charging relays
(2) Victron 12 volt/100 amp battery chargers for house and engine batteries
Victron 12 volt/3,000 watt Inverter
Galvanic isolator
Seakeeper 9 Gyro-Stabilizer
4-Zone 48,000 BTU HVAC System including optional fourth unit in pilothouse
LED house and machinery space lighting
LED courtesy lights in cockpit and head
LED navigation and anchoring lights
Dimmable, LED rope lighting in galley
12V outlet at helm and 110V weatherproof outlet with USB ports to port
Bonded electrical system per ABYC
Serviceable wiring, bundled and numbered with Deutsch O-ring waterproof connectors
Dirt Devil central vacuum system
Hella turbo fans in cabins

Mechanical And Plumbing

Quad Mercury Marine HD Verado 400 HP Gas Outboards – new 2024, 253 hours as of Feb 2026
Full service at 245 hours
Mercury Platinum warranties extended to 2032 at a cost of $30k
Mercury Active Engine Trim
Optional Reverso auto engine flush system
Sidepower bow thruster
Humphree Interceptors auto trim
Comprehensive engine spares kits and service manual
Single 920 gallon aluminum gas tank w/level gauge
(4) Machinery space air intakes
Seafire automatic fire suppressant system
Pressure hot/cold water with Johnson Aqua Jet Duo variable-speed water pressure pump
Sea-Ro watermaker (2025)
20 gallon stainless steel water heater
250 gallon polyethylene freshwater tank
Seagull IV drinking water purification filter
Dock-mate portable water filter (2023)
Hot/cold shower on swim platform
High-pressure fresh water (washdown in port cockpit locker with 50’ hose and nozzle)
(5) 110 automatic bilge pumps
(2) High water alarms
Arid Dry bilge system with three pick-ups (2023)
Dometic electric freshwater toilet system with 60 gallon holding tank, tank gauge in each head, deck pump out and macerator overboard discharge
Gray water sump w/ inspection for showers, head and AC condensate
Marelon non-corrosive thru-hulls/seacocks with oversized strainers and double-clamped hose

Hull And Deck

Modified deep-V hull with sharp entry, high length-to-beam ratio, dual lifting strakes, chine flats and 19-degree deadrise aft
ISO (CE Mark) Certified Category A Ocean
Solid keel, stem, and transom corners of E-glass/epoxy GRP
High density core around thru-hull and hardware attachments points
Bilges painted with smooth, gloss-white finish
PVC guardrail and 1/2 round SS rub rail
Hull and deck fused as monocoque structure
Insignia white deck gelcoat with light gray non-skid, completely refinished 2024
Hull finished with Awlcraft Bentley Blue with clear coat, white boot and cove stripes, and black bottom

Deck Details

Muir anchor windlass with deck and helm controls
Ultra 46 lb stainless auto-launching anchor with 250’ rode and 50' SS high-tensile chain
Freshwater anchor and rode washer control at helm
Polished stainless anchor guard and roller
13 lb Stern anchor
Retractable swim ladder
Stainless handrails on corner posts, hardtop, pilothouse, seat backs, console and companionway entrance
Stainless 30" cockpit guardrail and bow rail
(2) Custom stainless multi-directional bow chocks
(8) Opening overhead hatches on foredeck, cabin top and hardtop with dual action shade-screens
(6) Opening cabin portlights with combo screens/shades
(3) Machinery space access hatches with scuppers, overboard drains, gaskets, lockdowns and custom storage bags under hatches (2024)
Main hatch has electric operated lift and teak/stainless access ladder
Optional upgrade to Flexiteek bleached finished synthetic teak on pilothouse sole and swim platform
Pilothouse removable sole covers in a laid teak deck pattern
Laid teak decks on aft deck sole (new 2023)
Cockpit seat locker for dock lines, fenders etc.
Aft serving bar with tumbler storage and 110V icemaker (new 2023)
Teak cockpit table with cover
(2) Teak chairs and stools with padded storage bags (all new 2024)
Aft cockpit bimini (new 2025)
Custom hinged three-piece sun pad cushion forward (2024)
Custom engine covers (2024)
New exterior covers (2024)
Ensign with teak staff and retainer pin
Multiple padded fenders and dock lines

Safety And Misc

ARC EPIRB
(24) PFDs
(2) Inflatable PFDs
Winslow 6-man life raft
Life ring
Flare kit
First aid kit

Summary Of Recent Upgrades

2023

Laid teak decks on aft deck, treated and oiled
New icemaker aft deck bar
Arid Dry Bilge system with (3) pick-ups
Dock-Mate water filter

2024

Quad Mercury Marine HD Verado 400 HP Gas Outboards with extended warranties to 2032
Custom engine covers
All new Garmin electronics suite
Garmin rear view camera
Starlink system
New non-skid on decks and cabin top
Pilothouse windows tinted for cooling and sun protection
Sun pad forward
New exterior covers
Custom storage bags underside of deck hatches
(2) Teak deck chairs

2025