CI SEA - BOSTON BOAT WORKS FOR SALE

Flagship of the MJM range, with single-level social space from pilothouse to aft, private quarters for four, meticulous engineering and craftsmanship, and thrilling performance in a Downeast motor yacht and express cruiser.

Introduction

CI SEA is a late-model 2021 MJM 53z, envisioned by Doug Zurn and meticulously built by Boston Boatworks. As the Downeast-inspired flagship of the MJM line, she delivers expansive single-level entertainment spaces that flow effortlessly between the pilothouse and aft decks, private luxury accommodations for four, impeccable engineering and build quality, and genuinely impressive performance—precisely the attributes sought by a discerning yachtsman. Acquired nearly new in 2022, she has since benefited from comprehensive care and thoughtful upgrades, including new updated Mercury quad outboards with extended warranties, an all-new Garmin navigation suite, refreshed canvas and fabrics throughout, a laid teak sole on the aft deck, fully renewed deck non-skid, and a host of additional enhancements detailed herein. Her condition and specification are sure to impress upon inspection.

Interior

The interior showcases finely crafted cherry joinery, with cherry-paneled or louvered cabinet doors, solid drawer fronts, and elegant solid trim throughout, all finished in a refined satin varnish. Large surfaces are executed in varnished cherry veneer for visual warmth, while the gloss teak cabin soles with wenge inlays create a crisp, yacht-quality contrast beneath removable soft white overhead panels. Custom removable cabin-sole covers in a laid teak deck pattern add both protection and style. In 2024, CI SEA’s décor was tastefully refreshed with custom-fitted bedspreads, mattress covers, shams and accent pillows for each cabin, complemented by numerous new throw pillows in the pilothouse and aft cockpit. Two steps down from the pilothouse, the layout places a generous galley to port, the private guest cabin to starboard with adjacent day/guest head and shower, and a spacious full-beam master cabin forward with private access to its ensuite head and shower.

The galley is purpose-built and beautifully equipped with Corian countertops featuring a recessed sink with cutting board cover and a pullout faucet, three flatware and utensil drawers with organizer trays, a Vitrifrigo stainless 5.5 cu ft two-drawer refrigerator, and an Isotherm freezer compartment forward with convenient top access. A dedicated drop-front trash bin is set under the forward counter, while a large under-counter storage locker aft accommodates pots, pans, and cleaning supplies. Cooking is handled by a Wolf two-burner induction cooktop and a Breville toaster oven. Above, an extended shelf with storage cabinets and a secure grab-rail fiddle adds practicality, while a skylight hatch and an opening portlight maximize natural light and ventilation.

The guest cabin to starboard is a serene retreat with a double berth featuring a memory-foam mattress upholstered in UltraLeather, a fold-down desk for work or journaling, and an upholstered reading chair with armrests. A side table with drawers and a reading lamp sits at hand, and the space is bathed in daylight from a large fixed hull portlight with shade, an opening portlight, and an overhead hatch with screen and shade. Private access to the guest/day head enhances convenience for overnight guests.

Forward, the full-beam owner’s cabin centers on a fixed island queen berth with a memory-foam mattress clad in quilted Ultrasuede. Storage abounds with four drawers beneath the berth, shelves outboard on each side, and a cherry-framed forward bulkhead that integrates two recessed bookcases and double access doors to a large forepeak anchor locker. A reading chair with armrests in UltraLeather, a cherry desk/dressing table, and hanging lockers to port and starboard with storage shelves above complete the suite. A full-length dressing mirror graces the forward face of the entry door. Natural light and airflow are enhanced by two fixed hull portlights with shades, an opening cabin port, and two large cabin-top hatches with screens and shades.

Both the owner and guest heads are outfitted for comfort and cleanliness, with Corian counters and a white Corian oval sink, a glass-enclosed shower with seat, and a Dometic electric toilet with freshwater flush. Storage and practicality are addressed by an under-sink locker, towel rings and hooks, and a floor drain feeding a gray-water overboard system. The guest head also includes a hanging locker, while an overhead hatch and an opening portlight with screens and shades provide natural ventilation.

Pilothouse and aft cockpit

The spacious pilothouse is the primary command and social hub, fully enclosed for quiet operation and efficient climate control, yet able to transform into an open-air pavilion via opening windshields, side windows, and a rear door and window for a breezy, outdoor feel. Seating is generous and flexible, with helm and passenger chairs, a U-shaped dinette with table to starboard, and a full-length settee to port, all flowing aft on a single level to the cockpit where a fixed settee and two matching movable seats gather around a gloss-varnished teak table. Boarding is effortless thanks to side entry doors on each side and transom doors leading to the swim platform to port and starboard.

The specification elevates comfort and control with optional stainless Stidd 500 seating—a wide passenger chair and a double-wide piloting seat—alongside optional helm and co-pilot dashes and countertops in gloss-finished teak with flush-mounted electronics. An optional aft sliding glass door with fixed aft windows in a polished stainless frame and an optional electric-powered drop-down aft starboard window enhance versatility. Three full-opening electric windshields with wipers and washers deliver commanding ventilation and clear sightlines, complemented by sliding safety-glass three-part side windows with tinted treatment added in 2024 and drop-down Sunbrella privacy and sunshades. The helm is crowned by a 24" Edson destroyer wheel with a varnished teak rim and supported by footrests at each pedestal seat. A teak pilothouse table expands on an electric telescoping stainless pedestal, and the settees feature blue UltraLeather-covered memory-foam cushions that convert as needed into a double and a single, with a second set of new, unused white UltraLeather cushions in reserve. Storage is abundant, including clear Awlcraft-finished teak drawers with locks on each side, large settee lockers with mesh organizer bags for cords, hoses, bikes, hard luggage, a dinghy, and golf clubs, and a lockable companionway with a safety latch.

Piloting & navigation

A comprehensive 2024 navigation refit places intuitive control at your fingertips: two Garmin 8616 16-inch chart plotters at the helm are complemented by one Garmin 8612 12-inch chart plotter at the co-pilot station, a Garmin GMR Fantom 24 radar, and two Garmin GMI 20 instrument displays. Weather and connectivity are enhanced by a Garmin Sirius XM weather antenna, the Garmin NMEA 2000T network backbone, a Garmin rear-view camera, and a Starlink satellite system for reliable broadband afloat. Additional systems include a Raymarine Ray 218 VHF, Raymarine AIS 650 tracking, and a Mercury VesselView MFD controller with joystick docking, Skyhook station hold, and Autopilot. Night and low-visibility operations benefit from a 320,000 Candela LED articulating searchlight mounted on the bow rail, a Kahlenberg compressed-air horn with auto fog and anchor signals, a trustworthy Ritchie compass, and a FLIR M232 infrared camera on a pedestal with mast light on a hinged mounting plate.

Entertainment

Entertainment is seamless throughout with a Fusion MS-AV755 stereo driving a bass woofer and four pairs of speakers, complete with Sirius radio. A clever optional drop-down 42" smart TV over the companionway serves the pilothouse, while a 24" smart TV resides in the forward cabin and a 31" smart TV in the guest cabin. For content at sea, a KVH TV3 satellite Direct TV receiver dome shares a pedestal with the radar and navigation light, supported by a Glomex TV antenna.

Electrical

Electrical systems are organized for simplicity and redundancy, beginning with a custom backlit panel featuring 12V DC breakers, 240/110V AC breakers, and digital DC and AC monitors conveniently located near the companionway. Ship’s power is supported by a Westerbeke 9 kW genset showing 505 hours and serviced in Dec 2025, and a 110V AC system with a Victron Energy shore-power solution including a 65' white 50‑Amp cord and a Cable Master/Glendenning with remote control (2024). Battery capacity comprises three Group 8D AGM 245Ah house batteries and one Group 31 105Ah/800CCA per engine (new 2022), charged by 150‑amp alternators on each engine, Blue Seas automatic charging relays, and two Victron 12‑volt/100‑amp battery chargers, with a Victron 12‑volt/3,000‑watt inverter for silent AC power. A galvanic isolator protects metalwork, while a Seakeeper 9 Gyro‑Stabilizer calms motion. Climate control is assured by a 4‑Zone 48,000 BTU HVAC system, including an optional fourth unit dedicated to the pilothouse. Illumination is entirely LED, with house and machinery-space lighting, cockpit and head courtesy lights, and navigation and anchoring lights, plus dimmable LED rope lighting in the galley. Convenience features include a 12V outlet at the helm and a 110V weatherproof outlet with USB ports to port, an ABYC‑compliant bonded electrical system, serviceable bundled and numbered wiring with Deutsch O‑ring waterproof connectors, a Dirt Devil central vacuum system, and Hella turbo fans in the cabins.

Mechanical and plumbing

Performance and serviceability define the machinery package, led by quad Mercury Marine HD Verado 400 HP gas outboards—new in 2024 and showing 253 hours as of Feb 2026—with full service completed at 245 hours. Mercury Platinum warranties are extended through 2032 at a $30k investment, while Mercury Active Engine Trim, an optional Reverso auto engine flush system, a Sidepower bow thruster, and Humphree Interceptors auto trim deliver precise handling and easy upkeep. Operations are supported by comprehensive engine spares kits and a service manual, and fuel is carried in a single 920‑gallon aluminum tank with level gauge. Ventilation and safety are enhanced by four machinery‑space air intakes and a Seafire automatic fire‑suppressant system.

Freshwater systems are equally robust, featuring pressure hot/cold water via a Johnson Aqua Jet Duo variable‑speed pump, a Sea‑Ro watermaker (2025), a 20‑gallon stainless‑steel water heater, and a 250‑gallon polyethylene freshwater tank. Drinking water is polished by a Seagull IV purification filter, with dockside supply treated through a Dock‑mate portable water filter (2023). On deck, a hot/cold shower at the swim platform and a high‑pressure freshwater washdown in the port cockpit locker with a 50' hose and nozzle keep decks and gear pristine. Bilge management is comprehensive with five 110 automatic bilge pumps, two high‑water alarms, and an Arid Dry bilge system with three pick‑ups (2023). The Dometic electric freshwater toilet system includes a 60‑gallon holding tank, tank gauges in each head, deck pump‑out, and macerator overboard discharge, while a gray‑water sump with inspection serves showers, the head, and AC condensate. Below the waterline, Marelon non‑corrosive thru‑hulls and seacocks with oversized strainers and double‑clamped hose provide durable, low‑maintenance reliability.

Hull and deck

Designed for efficiency and seakeeping, the modified deep‑V hull blends a sharp entry, a high length‑to‑beam ratio, dual lifting strakes, chine flats, and a 19‑degree aft deadrise. Structural integrity is reinforced with ISO (CE Mark) Category A Ocean certification, solid E‑glass/epoxy GRP in the keel, stem, and transom corners, and high‑density core around all thru‑hull and hardware attachment points. Bilges are finished in smooth gloss white for easy inspection, while a PVC guardrail and 1/2‑round stainless‑steel rub rail defend topsides. Hull and deck are fused into a rigid monocoque. The deck is finished in Insignia white gelcoat with light‑gray non‑skid, completely refinished in 2024, and the hull gleams in Awlcraft Bentley Blue with a clear coat, white boot and cove stripes, and a black bottom.

Deck details

Anchoring and deck work are effortless with a Muir windlass controlled from deck and helm, an Ultra 46 lb stainless auto‑launching anchor on a polished stainless guard and roller, 250' of rode, and 50' of high‑tensile stainless chain, plus a freshwater anchor and rode washer controlled at the helm. A 13 lb stern anchor stands ready for precise positioning. Access to the water is via a retractable swim ladder, while stainless handrails on corner posts, the hardtop, pilothouse, seat backs, the console, and the companionway entrance provide complete security. Protection continues with a stainless 30" cockpit guardrail and a robust bow rail, two custom stainless multi‑directional bow chocks, eight opening overhead hatches on the foredeck, cabin top, and hardtop with dual‑action shade‑screens, and six opening cabin portlights with combination screens and shades. Machinery space is accessed via three hatches with scuppers, overboard drains, gaskets, lockdowns, and custom storage bags secured beneath (2024), while the main hatch lifts electrically and is served by a teak and stainless access ladder. Surfaces are refined with an optional Flexiteek bleached‑finish synthetic teak on the pilothouse sole and swim platform, removable pilothouse sole covers in a laid‑teak pattern, and laid teak decks on the aft deck sole installed new in 2023. Amenities include a cockpit seat locker for dock lines and fenders, an aft serving bar with tumbler storage and a 110V icemaker new in 2023, a teak cockpit table with cover, two teak chairs and stools with padded storage bags (all new in 2024), and an aft cockpit bimini new in 2025. Finishing touches include a custom hinged three‑piece forward sun pad cushion (2024), custom engine covers (2024), new exterior covers (2024), an ensign with a teak staff and retainer pin, and multiple padded fenders and dock lines.

Safety and misc

Safety equipment is comprehensive and thoughtfully selected, including an ARC EPIRB, twenty-four PFDs, and two inflatable PFDs for added redundancy. Offshore readiness is further supported by a Winslow 6‑man life raft, a life ring, a flare kit, and a well‑stocked first aid kit.

Summary of recent upgrades

In 2023, CI SEA received laid teak decks on the aft deck—carefully treated and oiled—an all‑new icemaker at the aft deck bar, an Arid Dry Bilge system with three pick‑ups, and a Dock‑Mate water filter to ensure clean dockside supply. The 2024 program delivered a transformative suite: new quad Mercury Marine HD Verado 400 HP gas outboards with extended warranties through 2032 and custom engine covers, an all‑new Garmin electronics suite with a Garmin rear‑view camera, and a Starlink system for fast, reliable connectivity. Exterior refinements included new non‑skid on decks and the cabin top, professionally tinted pilothouse windows for cooling and UV protection, a forward sun pad, new exterior covers, and custom storage bags installed on the undersides of deck hatches, plus two teak deck chairs. In 2025, a Sea‑Ro watermaker was added for true autonomy at anchor, along with a new upgraded bimini to shade the aft cockpit.

Exclusions

Owner’s personal effects are excluded from the sale, as is the coffee maker.