MJM 50z, Bob Johnstone's Triple-Pod Downeast Flagship
A J/Boats founder's idea of a power yacht, light, stiff and fast on three Volvo pods, with a single-stateroom plan that puts the owners first.
- Length
- 55.3 ft16.84 m
- Beam
- 15 ft4.57 m
- Cruise
- 25.3 kn
- Cabins
- 1 or 2
- Used price
- $1.05M to $1.65M
On this page
- Overview
- What a sailboat legend wanted from MJM's biggest power yacht
- A 55-foot boat that weighs less than many 45s
- Twin or triple Volvo IPS, and why three was the headline
- The numbers behind the triple-pod 50z
- An air-conditioned bridgedeck under a hardtop
- One stateroom by design
- Running costs for a triple-pod 50z
- Used MJM yachts and the 50z's rarity
- Specifications
- Price and value
- Strengths and weaknesses
- Used buyer checklist
- Rivals
- Our verdict
- FAQ
The MJM 50z is a 55-foot overall Zurn-designed express from MJM Yachts, built by Boston BoatWorks in an E-glass, Kevlar and Corecell composite. On triple Volvo IPS600 pods it ran 37.6 knots and cruised at 25 knots in testing.
- Experienced couples cruising without crew
- Former sailors moving to power
- Fast coastal passages from New England to Florida
- Owners who value efficiency over volume
What a sailboat legend wanted from MJM's biggest power yacht
MJM Yachts exists because Bob Johnstone, the co-founder of J/Boats and the man behind the J/24, decided that most power boats were heavier and thirstier than they needed to be. MJM boats apply sailboat thinking to power: light, stiff composite hulls, efficient shapes and clean, functional deck plans. Designer Doug Zurn of Zurn Yacht Design drew the hulls, Boston BoatWorks built them, and Johnstone wrote the specifications. Zurn described the process to Power and Motoryacht as a very straight, very clear path from Bob through the designer to the builder.
The MJM 50z was the largest expression of that idea when hull No. 1 launched in the summer of 2014, ahead of a debut at that fall's Newport and Fort Lauderdale shows, a big step up from the 29z, 34z, 36z and 40z that built the brand. It was aimed at owners who wanted to cover serious distance at speed, in comfort, without crew. The 50z is now on MJM's retired-models list, and the company describes it as a robust cruiser that celebrated MJM's Downeast heritage at a larger scale. Its current range has moved on to the X, V and R series, but the 50z remains one of the most interesting used MJM yachts on the market.
MJM 50z by the numbers
- Speed to length ratio at cruise
- 3.65A planing cruise. Fast passages in exchange for much higher fuel burn per mile.
- Estimated range at cruise
- 393 nmUsing 90 percent of tank capacity at the cruise speed and fuel burn listed on this page.
- Fuel economy at cruise
- 0.84 nmpgNautical miles per gallon at cruise, both engines combined.
- Horsepower per ton
- 79 hpStrong power to weight for a planing hull.
- Length to beam ratio
- 3.68 : 1A slim, easily driven hull.
A 55-foot boat that weighs less than many 45s
At 32,850 pounds displacement for a boat 55 feet 3 inches overall and 15 feet in beam, the 50z is remarkably light. The lamination schedule blends E-glass, Kevlar and Corecell foam core, using prepreg techniques and resin infusion, to get high stiffness at low weight. That is the key to everything else on the boat. Less weight means less power for a given speed, less fuel, a shallower draft and better range.
MJM's approach is the opposite of the traditional Downeast builder who adds weight for a solid feel. The 50z relies on hull shape and stiffness for its ride, and the standard Seakeeper gyro, a 1,210-pound unit positioned forward of the engine room, takes care of the roll at anchor and at slow speed. Owners used to heavy Downeast hulls should sea trial in a chop to be sure they like the livelier motion.
Twin or triple Volvo IPS, and why three was the headline
Standard power was a pair of Volvo Penta IPS600 pods, each rated at 435 hp, good for a top speed of about 33.8 knots according to MJM. The configuration that made headlines was three IPS600s, which Power and Motoryacht tested. Triple pods are rare on a boat of this size and give the 50z sportboat speed: 37.6 knots at 3,400 rpm and a 25-knot cruise at 2,500 rpm burning about 30 gallons per hour across all three engines.
Pods suit the 50z. The forward-facing propellers work in clean water, which improves efficiency, and the Volvo joystick with dynamic positioning lets one person hold the boat in place against wind and tide. On this boat the dynamic positioning eliminated the need for a bow thruster altogether. The trade-off is maintenance. Each pod needs regular service of oil, anodes, propellers and bellows, and three pods means three of everything. A triple-pod engine room is also more crowded than a twin.
The numbers behind the triple-pod 50z
The Power and Motoryacht test boat carried 265 gallons of fuel, 130 gallons of water and two people. At 600 rpm it idled along at 4.1 knots on 1.1 gallons per hour, giving a theoretical range of more than 1,700 nautical miles. At 1,500 rpm, 11.1 knots used 9.9 gallons per hour. At 2,500 rpm the boat made 25.3 knots on 30.1 gallons per hour, about 393 miles of range. Wide open at 3,400 rpm it reached 37.6 knots on 65 gallons per hour.
Sound levels were impressive, 75 dB at 11 knots and 79 dB at 25 knots, reflecting both the pod installation and the stiff hull. With 520 gallons of fuel, the 50z can run from Newport to Nantucket and back at cruise speed with plenty of reserve, or reach the Bahamas from South Florida easily.
An air-conditioned bridgedeck under a hardtop
The helm deck is the 50z's center of gravity. It sits under a hardtop and is climate controlled with a Marine Air system, enclosed with removable Strataglass curtains so it can be fully open in summer and sealed in the shoulder seasons. Side seating lines the bridgedeck with lockers opening into large stowage areas. An optional bimini folds aft and stows above the transom for shade in the cockpit.
Aft, the Sealift hydraulic swim platform lowers into the water for swimming and can launch and retrieve a tender of up to 2,500 pounds. That turns the 50z into a true expedition cruiser for a couple, with no need for a davit.
One stateroom by design
Below decks the standard 50z has a single, en suite master stateroom forward with hanging lockers, a desk and a fixed chair. It is a plan for a couple who travel alone and occasionally host guests, rather than a family boat. The saloon and galley are aft of the master, the dinette converts to a guest berth, and a separate day head with its own stall shower serves guests.
An optional second stateroom was available, but it eliminates the saloon dinette. Most buyers stuck with the single stateroom, which is part of why the 50z feels so spacious for its displacement. Guests who stay more than a night or two will be happier in a marina hotel.
Running costs for a triple-pod 50z
Annual costs for a 50z typically run from $60,000 to $120,000 excluding depreciation. The big items are a 55-foot slip, insurance on a $1 million-plus boat, IPS service on two or three pods, Seakeeper maintenance, the generator and climate control systems, canvas and Strataglass replacement.
Fuel is surprisingly reasonable for the size. At 25 knots the triple-pod boat burns about 30 gallons per hour, comparable to many 40-foot twin-diesel express boats. Slow to 11 knots and the burn drops to about 10 gallons per hour, ideal for longer passages.
Used MJM yachts and the 50z's rarity
MJM built the 50z in small numbers, and well-maintained examples are rare on the brokerage market. Used MJM yachts for sale tend to hold value well thanks to a loyal following among experienced boaters, many of them former sailors who appreciate the brand's efficiency and engineering.
The 50z is a niche boat. Its single-stateroom plan and lively, light-hull motion do not suit every buyer, which narrows the market. But for the right owner it offers performance, efficiency and finish that few competitors match, and boats with documented pod and Seakeeper service sell quickly.
MJM 50z specifications
| Length overall | 55.3 ft16.84 m |
|---|---|
| Beam | 15 ft4.57 m |
| Draft | 3 ft0.91 m |
| Displacement | 32,85 lbs14,901 kg |
| Fuel capacity | 52 gal1,968 L |
| Fresh water | 17 gal644 L |
| Cabins | 1 or 2 |
| Berths | 2 to 4 |
| Heads | 2 |
| Standard engines | 2 x Volvo Penta IPS600 (435 hp each) pod drives |
| Optional engines | 3 x Volvo Penta IPS600 (435 hp each); triple Yanmar 8LV 370 hp sterndrives were also listed as an option |
| Maximum power | 1,305 hp |
| Cruise speed | 25.3 knots |
| Top speed | 37.6 knots |
| Range | 393 nm |
| Hull type | Modified-V planing hull optimized for pod drives |
| Hull construction | Resin-infused and prepreg E-glass, Kevlar and Corecell composite |
| Builder | Boston BoatWorks for MJM Yachts, USA |
| Naval architect | Zurn Yacht Design (Doug Zurn) |
| Other design credits | Bob Johnstone, MJM Yachts founder and J/Boats co-founder (concept and specification) |
| Production | 2014 to present |
| Status | Discontinued |
Figures come from builder documentation and independent tests where available. Displacement is usually quoted light, so a loaded cruising boat will weigh more. Compare these specs with another model.
Performance data
| RPM | Speed (kn) | Fuel (gph) | Range (nm) |
|---|---|---|---|
| 600 | 4.1 | 1.1 | 1744 |
| 1500 | 11.1 | 9.9 | 525 |
| 2500 | 25.3 | 30.1 | 393 |
| 3400 | 37.6 | 65 | 271 |
Power and Motoryacht test, January 2016 issue, triple Volvo Penta IPS600. Load 265 gallons fuel, 130 gallons water, two people, 200 pounds gear.
How much does a MJM 50z cost?
Triple IPS boats command the strongest prices because they deliver the 35-knot-plus performance the 50z is known for, while twin IPS boats trade lower. Engine hours, pod service history and the condition of the Seakeeper and Sealift platform are the big swing factors. Price as tested in 2016 for a triple IPS boat was $2,075,000.
Estimate your yearly cost
A planning estimate using common rules of thumb: insurance near 1.5 percent of value, maintenance near 3 percent, haul out and bottom paint by length. Your marina, region and use will move these numbers. Open the full cost calculator.
Versions and options
- Twin IPS600
- Standard configuration with two 435 hp Volvo IPS600 pods and a 3-foot draft. Lower purchase price and simpler maintenance.
- Triple IPS600
- Three 435 hp pods for a 37.6-knot top speed and 25-knot cruise. The most sought-after version, with a 3-foot-10 draft.
- Two-stateroom option
- Adds a second cabin at the expense of the saloon dinette.
MJM 50z timeline
- 1970sBob Johnstone co-founds J/Boats, later the inspiration for MJM's light-boat philosophy
- 2014Hull No. 1 of the 50z launches in summer and the boat debuts at the fall Newport and Fort Lauderdale shows
- 2016Power and Motoryacht tests the triple IPS 50z at 37.6 knots, price as tested $2,075,000
- 2018MJM announces the outboard-powered 53z as its next flagship, with deliveries planned for 2019
- 2026The 50z is a retired model, with MJM's range now built around the X, V and R series
Strengths and weaknesses
What owners like
- Light, stiff composite hull with excellent efficiency
- Triple IPS option gives 37-knot performance
- Volvo dynamic positioning and joystick make single-handing practical
- Standard Seakeeper gyro
- Hydraulic swim platform lifts a 2,500-pound tender
- Shallow draft for a 55-foot boat
What to weigh up
- Single-stateroom plan limits guest capacity
- Triple pods mean triple maintenance
- Light hull has a livelier motion than heavy Downeast boats
- Small production numbers limit the used market
- No longer in production
Used MJM 50z buyer checklist
Take this list to a viewing. Your ticks are saved in this browser so you can come back to it.
Always commission an independent marine survey and an engine survey before you buy. How a marine survey works.
Rivals to consider
Hinckley Talaria 48
Jet-driven Downeast flagship with traditional finish and more prestige, heavier and more expensive.
Sabre 48 Salon Express
Heavier Maine-built express with more accommodation and a more traditional ride.
Palm Beach GT50
Light, fast Australian-built cruiser with a similar efficiency-first philosophy and stylish finish.
Wajer 55
Dutch-built dayboat with similar speed and a more open layout, less suited to long-range cruising.
Compare side by sideOur verdict on the MJM 50z
The MJM 50z is a boat for owners who think like sailors: light, efficient and engineered from the hull up, with a single-stateroom plan that puts the couple aboard first. On triple IPS pods it is quicker than almost anything with a Downeast profile and burns no more fuel at cruise than many smaller boats. Buy one with documented pod and Seakeeper service, accept the livelier motion and limited guest space, and you will own one of the most capable short-handed cruisers of its era.
MJM 50z questions answered
What is MJM Yachts known for?
MJM Yachts, founded by J/Boats co-founder Bob Johnstone, builds light, efficient Downeast-styled power yachts designed by Zurn Yacht Design. The brand is known for engineering, efficiency and strong resale.
How fast is the MJM 50z?
With triple Volvo IPS600 pods the 50z tested at 37.6 knots top speed and cruised at about 25 knots burning 30 gallons per hour.
How much does a used MJM 50z cost?
Used MJM 50z yachts typically list between about $1.05 million and $1.65 million depending on year, engine configuration and condition.
Who builds MJM yachts?
The 50z and earlier MJM models were built by Boston BoatWorks, with hull designs by Doug Zurn of Zurn Yacht Design.
Is the MJM 50z still in production?
No. The 50z is on MJM's retired models list. The current range is built around the X, V and R series.
How many cabins does the MJM 50z have?
The standard layout has a single en suite master stateroom, with an optional second stateroom that replaces the saloon dinette.
