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If your retirement plans call for casting off the lines and heading off for distant shores to explore your horizons, then have we got a boat for you. Not only is the 40z remarkably fuel-efficient, but she is also built to demanding standards in terms of strength and sea-keeping abilities. She is a very unusual boat from almost any standpoint and we think she is truly exceptional.

Key Features

  • Powered by twin Volvo Penta D6 IPS500
  • Standard radar and autopilot
  • Standard swim ladder and swim platform
  • Standard trim tabs
  • Freshwater washdown
  • Optional Seakeeper gyrostabilizer
  • Optional powered windshields
Length Overall 43' 2''
13.16 m
Beam 12' 0''
3.7 m
Dry Weight 17,450 lbs.
7,915 kg
Tested Weight N/A
Draft 3' 3''
0.99 m
- Draft Up N/A
- Draft Down N/A
- Air Draft N/A
Deadrise/Transom 19 deg.
Max Headroom N/A
Bridge Clearance N/A
Weight Capacity N/A
Person Capacity N/A
Fuel Capacity 350 gal.
1,324.9 L
Water Capacity 100 gal.
378.5 L
Length on Trailer N/A
Height on Trailer N/A
Trailer Weight N/A
Total Weight
(Trailer, Boat, & Engine)

Prices, features, designs, and equipment are subject to change. Please see your local dealer or visit the builder's website for the latest information available on this boat model.

Std. Power 2 x 370-hp Volvo Penta D6 IPS500
Tested Power 2 x 435-hp Volvo Penta IPS600
Opt. Power Not Available

by Capt. Steve Larivee

MJM 40z
At 43' 2" (13.16 m), some may feel that the 40z is too big for a shorthanded crew. We'll show that it's not.

How Efficient?

Our test of the MJM 40z was powered by twin Volvo Penta IPS600s developing 435-hp. So let's start by checking out the claim that this boat is fuel-efficient. Our tests show that the 40z reached a top speed of 40.2 kts (46.3 mph) at 3550 rpm. At that speed we were burning 44 gph (166.6 lph) for a range of 288 nautical miles.When we compare that top speed with other hardtop 40-something express cruisers with a displacement of 18,000 lbs. to 22,000 lbs., I find that she was the fastest of seven boats I looked at. They all had less horsepower except two, and the MJM 40z was from 6 to 8 mph faster at WOT than those two boats.

Best Cruise Tells the Tale

Best cruise is basically a combination of good speed and miles per gallon. Now, from 2000 to 2750 rpm our miles per gallon ranged from 1.48 nautical miles per gallon to 1.30 nmpg. When we compare the best cruise speeds of 7 other boats in class with the MJM 40z, we find that the she is more fuel efficient than all of them, ranging from about 22% to as much as 70% more fuel efficient. None of these are apples-to-apples comparisons because of many variables including engine horsepower, drives, and boat displacement. Nevertheless, it is clear that the MJM 40z when powered by twin Volvo Penta 435-hp IPS600s is exceedingly efficient, even when compared to other boats with IPS drives. When it comes to time-to-plane, the 40z smokes boats even much smaller and lighter. I recorded only 4.4 seconds to plane, and we reached 20 mph in only 5.6 seconds, and 8.6 seconds to reach 30 mph. These are times you might expect to find with a sportboat.Complete test results can be seen by clicking on the test results tab above this report.

Efficient by Design

A lot of that efficiency comes from adopting racing sailboat technology. The 40z is largely the brain child of Bob Johnstone, the "J" of J/Boats sailboat fame, and inarguably a man who knows a bit about how to tweak the best performance out of a hull design. But his concept of the ideal cruising powerboats is only half the battle. A naval architect with a good eye was needed to complement the boat's functionality. For that Johnstone turned to famed architect, Doug Zurn. As a result of Doug's design contribution, the "Z" was added after the size moniker of each MJM model, and thus we have in this case… the 40z. For the build, Johnstone turned to Boston Boat Works (BBW), because no one else in the power boat field had the technology and because of their 35 year reputation for building successful world championship and Olympic winners in sailboats.

A Combination of Methods

Master Builder Mark Lindsay at BBW uses a wet prepreg epoxy, Kevlar, Eglass and Corecell composite which is vacuum set and oven post cured. No one else in the industry is doing this on a production boat. What comes from such a strong, light, and long lasting build is superior handling, more speed for HP applied, fuel efficiency and a low vertical center of gravity. The epoxy is forced into the Kevlar/Eglass material by high pressure rollers before it is laid into the boat with the glass fibers running the full 40' instead of being chopped up into short strands. The folks at MJM tell us that with this method BBW is able to get a glass-to-resin ratio of 60%, rather than just the opposite which is typical of the industry. The resin is just the glue, so the higher the glass to resin ratio the higher quality the construction.Epoxy also has better adhesion and is 25% stronger than polyester and vinyl ester resins. It also has more of an ability to elongate without failing over time. As Eric Sorenson, Soundings Technical Editor, commented, “Those MJMs are built like the Boeing Dreamliner, they are going to last 100 years or more!”.BBW and MJM are able to have a lighter boat that operates with less horsepower, while maintaining strength enough to have a rating that allows for offshore conditions. The MJM 40z as well as its new 50z are the only Down East style boats of any size that are certified ISO (CE) Category A Ocean, the highest rating for seaworthiness and offshore safety available. Category A says the vessel has the stability and strength to be going 45 knots in 21' seas.

The Layout

MJM 40z
An interior layout for the MJM 40z.

Now because we have a full walkthrough video, we'll just touch on the highlights of what makes the 40z such an ideal cruiser. It starts with the access. Large side doors to either side of the cockpit make boarding a step-in affair as opposed to a climb-in affair. This is much more appropriate for the aging set that this boat appeals to. The base of the doors is 24" (61 cm) off the surface of the water, so not only is it a gentle step across from a floating dock, but it's equally easy to board from a dinghy. And if you are relegated to tying up to a fixed pier, you can step down onto the wide caprails, and down easy steps into the cockpit.

MJM 40z
How easy would it be to carry supplies onboard with these convenient access doors? There are wide caprails for those laying against a floating dock.

Once aboard, the boat's single level layout is welcoming and accommodating for loads of guests. A full beam aft bench seat faces two double wide aft facing seats just ahead. Two opposing settees are in the helm deck, again on the same level as the cockpit, and a table expands to dining from both simultaneously.

MJM 40z
With a single level right up to the bulkhead in front of the helm, you have a boat that is easy for everyone to access regardless of where you want to be. Notice the steps up to the side decks.
MJM 40z
The forward seats swivel around to join the crowd at the settees. The table opens double wide to allow dining from both couches. The sides are wide open on the Downeast design and enclosed in the Express. The storage under the settees is absolutely cavernous. Notice how the windshields open to the horizontal.
MJM 40z
This is ingenious. The companionway hatch closes to form a chart table right next to the helm navigational center.

Of course, when cruising, you can't take your car with you, and typically, a bike becomes the next best thing. How many times have you seen cruising sailboats with bikes lashed to the rails? Such an arrangement would not do with the 40z, but under the two settees on the bridge deck is cavernous storage that can swallow two full size bikes, the golf clubs, and whatever else you'd like to bring along. Our test boat even had a deflated Avon dinghy in one of these compartments, and it still had room for plenty more.

Below Decks

Down below, there's a single stateroom, which makes a lot of sense. Why have a second stateroom for the 10% of the time another couple will be staying with you? No, better to have the dinette convert to a second berth, and MJM accommodates privacy with a curtain that hooks to the overhead. Now our couple has the entire boat to use while still accommodating the occasional second couple. If a third couple decides to join the cruise, the twin settees abaft the helm will convert to berths and another privacy curtain provides the seclusion.

MJM 40z
Here you can really see the sailboat heritage of the 40z. Notice the shelf above and below the table, and with refrigerated drawers in the galley, you won't be dumping contents out when you want a drink. The shelf above the galley has a grab area in its full length, and there's a stainless grab rail above.

But the best part is there are grab handles virtually everywhere. Three, right at the helm alone, duplicated for the observer. Making a sandwich at the galley, there's a handle overhead, and another in front ahead of a storage shelf. No matter where you are on this boat, there's something to hold onto.


With only two onboard, it's best to have both sets of eyes looking ahead. The 40z accommodates this with a pair of Stidd helm seats that are very comfortable. Optional seats are over-wide. Both seats swivel to join the crowd in the double settees just abaft, and when facing ahead, they are surrounded by so much glass that you'd think you were outdoors. And lest you worry about greenhouse effect, the front windows open up to the horizontal allowing plenty of air to flow through if you choose not to start the air conditioning. The helm gets a 14" (35.6 cm) navigational display, but no dedicated cruiser in his or her right mind would settle for relying only on electronics. Close off the companionway, and the top hatch becomes a chart table. Now, with the autopilot engaged, you can stand in the middle of the boat and simultaneously keep an eye on the paper charts, the helm, the navigational display, and the water. It's a delivery captain's dream boat, and a cruising couple's dream come true.

The Master

The master stateroom has a few tricks up its sleeve. The top half of the berth is wider than the lower half and that's how it should be. Your arms take up more space than your legs and this clever design allows for more room to move about the cabin. There is a hatch at the entry to the stateroom and another over the pillows. Why? Two reasons… first, you can lie in bed and stargaze quite easily, and second, if you anchor out, you can open the hatch and stand on the bed with the deck at your waist while you check and adjust the ground tackle… all without leaving the berth. Brilliant!

MJM 40z
Just stand on the bed and you can check the ground tackle without leaving the stateroom, or bothering your other guests.

There is a water closet to port with a commode and sink, plus a separate shower to starboard. With this design, two people can get ready for a night on the town at the same time. If both want to shower at the same time, they can use the water closet as a wet-head with its pull out sprayer at the sink.


Our test boat didn't have a dishwasher, and I don't feel the need for one. Two people will use only a few dishes and you need just a sink for that. However, the 40z has a clever storage area recessed into the counter that holds those wet dishes and allows them to dry in storage. The table across from the galley is beautiful and lined with teak planking ala sailboat, and a shelf below has a computer plug so you can bring your laptop without having the cord running all over the place. Oh, and the deck… while it may look like a brilliantly varnished teak and holly sole, it's actually coated in clear Awlgrip. This is much more durable than varnish, so go ahead and wear your shoes while onboard. This boat is made to be used, not kept under glass.

Other Design Considerations

There are a few other mentionable areas about the 40z. Some may notice that she has a somewhat narrow beam at 12' (3.7 m). While this may be narrower than others in class, it's not by accident. First, it aids in the performance. Second, it keeps the weight down. But most importantly, if you live in dual locations (like Maine and Florida) you can now transport your 40z over the road more cost effectively. At this width, you won't need to pay extra for escort vehicles. And transporting the boat from north to south and back is a lot faster and less expensive than moving the boat on her own bottom.The 40z is built around the IPS pods which add interior space, and has a proven economic advantage as we have seen.

Two Versions

Finally, the 40z comes in two versions. The Downeast, with open sides, or an Express with glassed in helm deck. Our test boat was the Downeast version and with roll down curtains (secured to the inside of the overhead to eliminate gathering rain water), we were able to enclose our boat quite easily. In my opinion, this boat really does represent the ideal combination of capable cruiser or a large day boat, while adding remarkable efficiency. I've had my share of gripes with various boats, as everyone knows (handrails, footrests, helms that don’t fit right, rails too short…), but these gripes are all met and put to rest on the 40z.


At an MSRP of $989,000 the MJM 40z is not for everyone. Rather, she is for a couple that appreciates a fine-looking, state-of-the-art Downeast cruiser that has no peer. With her, a couple can cruise securely from Nova Scotia to the Bahamas economically and with security, come what may. Very few express cruisers have a CE Category A Ocean rating. While I doubt that many people will do it, the fact is that at 8 knots she could make it to Bermuda. It is nice owning a boat that can do that, even if you don't take her there.If you are in the market for a picnic boat, a harbor cruising entertaining platform, or a fast express cruiser for a dash to Maine or Martha's -- and you want to arrive in style -- this could be the boat for you.

Test Result Highlights

  • Top speed for the MJM 40z (2012-) is 46.3 mph (74.5 kph), burning 44.00 gallons per hour (gph) or 166.54 liters per hour (lph).
  • Best cruise for the MJM 40z (2012-) is 23.7 mph (38.1 kph), and the boat gets 1.69 miles per gallon (mpg) or 0.72 kilometers per liter (kpl), giving the boat a cruising range of 533 miles (857.78 kilometers).
  • Tested power is 2 x 435-hp Volvo Penta IPS600.

Marine Electronics

Autopilot Standard
GPS/Chart Standard
Radar Standard
VHF Radio Standard


Air Cond./Heat Optional
CD Stereo Optional
Head: Fixed Standard
Shore Power Standard
Trim Tabs Standard
TV/DVD Optional
Washdown: Fresh Water Standard
Water Heater Standard
Windlass Standard


Icemaker Standard
Microwave Standard
Refrigerator Standard
Stove Standard

Exterior Features

Hardtop Standard
Outlet: 12-Volt Acc Standard
Swim Ladder Standard
Swim Platform Standard
Transom Door Standard


Bimini Top Optional

Boats More Than 30 Feet

Davit Optional
Generator Optional


Blistering Warranty
10 Year


Pricing Range: $1,025,000.00

Prices, features, designs, and equipment are subject to change. Please see your local dealer or visit the builder's website for the latest information available on this boat model.

Test Results - Change Measurement Unit

RPM MPH Knots GPH MPG NMPG Stat. Mile NM dBa
600 5.2 4.5 0.8 6.4 5.6 2028 1763 69
1000 8.3 7.2 2.1 4.1 3.5 1275 1109 69
1250 10.1 8.8 4.0 2.6 2.2 805 700 76
1500 12.0 10.4 6.4 1.9 1.6 591 514 72
1750 15.6 13.6 9.1 1.7 1.5 540 470 73
2000 19.6 17.0 11.5 1.7 1.5 536 466 75
2250 23.7 20.6 14.0 1.7 1.5 533 464 76
2500 28.4 24.7 18.0 1.6 1.4 496 431 77
2750 32.2 28.0 21.5 1.5 1.3 472 410 78
3000 36.3 31.5 26.0 1.4 1.2 439 382 82
3250 40.7 35.4 32.5 1.3 1.1 394 343 82
3500 45.3 39.3 39.5 1.2 1.0 361 314 81
3550 46.3 40.2 44.0 1.1 0.9 331 288 81
600 1763 3264 8.40 3.03 2.74 69
1000 1109 2052 13.40 7.76 1.72 69
1250 700 1296 16.30 14.95 1.09 76
1500 514 951 19.30 24.23 0.80 72
1750 470 869 25.10 34.45 0.73 73
2000 466 863 31.50 43.53 0.72 75
2250 464 858 38.10 53.00 0.72 76
2500 431 798 45.70 68.14 0.67 77
2750 410 760 51.80 81.39 0.64 78
3000 382 707 58.40 98.42 0.59 82
3250 343 634 65.50 123.03 0.53 82
3500 314 581 72.90 149.52 0.49 81
3550 288 533 74.50 166.56 0.45 81

All fuel consumption numbers are the total for all engines in the boat. Speeds are measured with Stalker ProSports radar gun or GPS. Fuel consumption (gallons per hour) measured with Floscan digital fuel-flow meter or by on-board factory-installed diagnostic instruments. Range is based on 90% of published fuel capacity. Sound levels determined using Radio Shack digital decibel meter on A scale. 68 dBA is the level of normal conversation. Time to plane is measured from start of acceleration to formation of rooster tail behind boat.