Overview

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.

The interior features finely crafted cherry joinerwork including cherry paneled or louvered cabinet doors, solid drawer fronts, and solid trim throughout, finished off in satin varnish. Large surfaces are optional varnished cherry veneer. Cabin soles are gloss teak with wenge inlays for a sharp look, with removable soft white overhead panels. There are also custom removable cabin sole covers in a laid teak deck pattern. The décor details for CI SEA were tastefully updated in 2024 including custom fitted bedspreads, mattress covers, shams and accent pillows for each cabin. There are also numerous new throw pillows for the pilothouse and aft cockpit. Two steps down the companionway from the pilothouse brings one to a generous galley to port with the private guest cabin starboard and day/guest head with shower. The spacious full-beam master cabin with private access ensuite head and shower is forward.

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.

CI SEA has been maintained and updated with numerous recent upgrades including 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, new exterior covers, custom storage bags underside of deck hatches, new teak deck chairs, and a new upgraded bimini in 2025. The yacht features a modified deep-V hull with sharp entry, high length-to-beam ratio, dual lifting strakes, chine flats and 19-degree deadrise aft. The hull is ISO (CE Mark) Certified Category A Ocean. The hull and deck are fused as monocoque structure with Insignia white deck gelcoat with light gray non-skid, completely refinished in 2024. The hull is finished with Awlcraft Bentley Blue with clear coat, white boot and cove stripes, and black bottom.

CI SEA is powered by quad Mercury Marine HD Verado 400 HP Gas Outboards, new in 2024, with 253 hours as of Feb 2026, full service at 245 hours, and Mercury Platinum warranties extended to 2032 at a cost of $30k. The yacht includes a comprehensive engine spares kit and service manual, sidepower bow thruster, Humphree Interceptors auto trim, and a Seakeeper 9 Gyro-Stabilizer. The electrical system includes a Westerbeke 9 kW genset with 505 hours, serviced Dec 2025, 110V AC system with Victron Energy Shore power system, batteries including (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, and a galvanic isolator.

Features

Designed by Doug Zurn
Built by Boston Boatworks
Late model 2021 MJM 53z
Expansive single-level entertainment spaces between pilothouse and aft decks
Luxury private accommodations for four
Finely crafted cherry joinerwork with satin varnish finish
Gloss teak cabin soles with wenge inlays and removable soft white overhead panels
Custom removable cabin sole covers in laid teak deck pattern
Updated décor details in 2024 including custom fitted bedspreads, mattress covers, shams, accent pillows, and throw pillows
Generous galley to port with Corian countertops, recessed sink, cutting board cover, pullout faucet, flatware and utensil drawers with organizer trays
Vitrifrigo stainless 5.5 cu ft. 2-drawer refrigerator
Isotherm freezer compartment forward with top access
Dedicated drop-front trash bin under counter forward
Under-counter storage locker aft for large pots/pans and cleaning supplies
Wolf 2-burner induction cooktop
Breville toaster oven
Extended shelf with storage cabinets and grab-rail fiddle above galley
Skylight hatch and opening portlight to maximize light and ventilation
Guest cabin with double berth, memory foam mattress covered in UltraLeather, fold-down desk, upholstered reading chair with arm rests, side table with drawers and reading lamp, large fixed hull portlight with shade, opening portlight and overhead hatch with screen and shade, private access to guest/day head
Forward cabin with fixed island queen berth with memory foam covered in quilted Ultrasuede, below-berth storage drawers, storage shelves outboard berth each side, cherry framed forward bulkhead with (2) recessed bookcases and double access doors to large forepeak anchor locker, reading chair with arm rests upholstered with UltraLeather, cherry desk/dressing table, hanging lockers each side with storage shelves above, private head and ensuite shower, full-length dressing mirror on forward face of entry door, (2) fixed hull portlights w/ shades, opening cabin port, and (2) large cabin top hatches with screens and shades for enhanced light and ventilation
Ensuite owner and guest heads with showers, Corian counter with white Corian oval sink, glass enclosed shower with seat, Dometic electric toilet with freshwater flush, under-sink storage locker, towel rings and hooks, floor drain to gray water overboard system, hanging locker in guest head, overhead hatch and opening portlight w/ screens and shades
Pilothouse with multiple seating including helm and passenger seats, U-shaped seating with table to starboard, full-length settee to port, 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
All new 2024 Garmin electronics suite including (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 piloting and navigation 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 system: 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 system: 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 Sea-Ro watermaker, new upgraded bimini