Access More Boat Tests

Captain's reports and/or test numbers for this model are archived.

To get full access to this content, please:

login   or   Register

Sea Ray SLX 400 OB (2021-)

3 x 300-hp Mercury Verado JPS

Brief Summary

Sea Ray refers to the SLX 400 OB as “The Entertainer” and that description is spot on. The original SLX 400 with sterndrives won the Innovation Award. This takes that same boat to the next level with outboard power, thereby meeting the demands of a growing market segment.

The Sea Ray SLX 400 offers incredible versatility that allows her to be reconfigured for whatever use an owner desires… be it watersports, swimming, coving, entertaining or overnighting.

Test Results

600 3.8 3.3 2.4 1.6 1.4 534 464.7 56
1000 6.1 5.3 4 1.5 1.3 510 443.9 57.2
1500 8 7 6.4 1.3 1.1 422 366.8 64.1
2000 10.1 8.7 10.7 0.9 0.8 317 275.7 67.8
2500 11.4 9.9 13.5 0.8 0.7 283 246 72.2
3000 13.9 12.1 22 0.6 0.5 213 185.4 75.1
3500 21.1 18.3 26.4 0.8 0.7 269 234 76.8
4000 32.9 28.6 34.8 0.9 0.8 319 277 80.4
4500 38.4 33.3 42.7 0.9 0.8 303 263.6 82.5
5000 41.9 36.4 58 0.7 0.6 244 211.8 82.5
5500 48.5 42.2 70.6 0.7 0.6 232 201.8 84.7
5900 51.8 45 72 0.7 0.6 243 210.9 87.5


Length Overall 41'11"
12.77 m
Beam 12'1"
3.68 m
Dry Weight 18,537 lbs.
8,408.24 kg
Tested Weight 19,758 lbs.
8,962.08 kg
Draft 45"
114 cm
Deadrise/Transom 21 degrees
Fuel Capacity 375 gallons
1,419.53 L
Water Capacity 50 gallons
189.27 L
Total Weight 19,758 lbs.
8,962.08 kg

Acceleration Times & Conditions

Time to Plane 4.8 seconds
0 to 30 9.5 seconds
Props 16 x 18 Eco Enertia
Load 3 persons; 1/4 fuel; 1/2 water; 50 lbs. gear
Climate 86 deg.; 56 humid.; winds: 20-25; seas: <1

Engine Options

Tested Engine 3 x 300-hp Mercury Verados JPS
Std. Power 3 x 300-hp Mercury Verados JPS

Captain's Report

By Capt. Steve

Sea Ray SLX 400 OB

The Sea Ray SLX 400 OB is a big bowrider with overnight accommodations. 


The Sea Ray SLX 400 OB is the company’s premium-level entertainment platform.  She’s a large bowrider that morphs into a staging area for so many functions that it’s hard to believe Sea Ray managed to fit them all into one boat and still leave so much space onboard, ensuring that no one feels cramped or has to squeeze past areas to transition through the whole boat.

Sea Ray SLX 400 OB Layout

There’s room for at least 15 people on deck and overnight accommodations for four. 

Major Features on the Sea Ray SLX 400 OB

  • The Sea Ray SLX 400 OB has an expansive cockpit social zone that has a well-appointed wet bar with a refrigerator, sink and available dual grills. The innovative new transom patio wing opens to extend the cockpit all the way to the water.
  • The bow has forward touring seats with armrests, U-shaped benches and a table.
  • Swim platform that comes out 16" (40.64 cm) from the transom. 
  • Premium Fusion audio system with Bluetooth, Wi-Fi audio streaming with Apple AirPlay 2 and Digital Signal Processing (DSP).
  • Fiberglass hardtop with optional aft extended sunshade and bow sail shade system.
  • For overnighting, the Sea Ray SLX 400 OB has premium comforts that extend to the cabin via a queen-sized bed in the aft section and a forward bunk that converts to form a social gathering area.
  • Dual Digital Dash with standard 16” (40.64 cm) Simrad touchscreen displays.
  • Complimentary 3-month subscription to Sea Ray Connect, powered by NAUTIC-ONTM smart boating technology, featuring remote monitoring of status and diagnostics via a smartphone app.
  • Optional Design, SLX-R and Elite Plus packages available.


The 2021 Sea Ray SLX 400 OB has a length overall of 41’11” (12.77 m), a beam of 12’1” (3.68 m) and a draft of 45” (114.3 cm). With an empty weight of 18,537 lbs. (8,408 kg), 1/4 fuel and three people onboard, we had an estimated test weight of 19,758 lbs. (8,962 kg). With the triple 300-hp Mercury Verados with JPS turning 16 x 18 Eco Enertia props and wound up to 5900 RPM, our speed topped out at 51.8 MPH. Best cruise was measured at 32.9 MPH and 4000 RPM. At that speed, the 34.8 GPH fuel burn translated in 2.9 MPG and a range of 319 statute miles, all while still holding back a 10% reserve of the boat's 375-gallon (1,419.53 L) total fuel capacity.


The Sea Ray SLX 400 OB is an excellent boat to drive, seemingly with plenty of power to spare. At first, I questioned her triple 300-hp engines as not being enough for this heavy boat but that was quickly dispelled. These are the new 8-cylinder technology engines from Mercury and offered plenty of power to spare. In fact, because the larger engines are V6s these engines easily made the grade as the correct choice from Sea Ray. She was very responsive to the throttles, coming on plane in an average of 4.8 seconds, reaching 20 MPH in six seconds, continuing through 30 in 9.5 and 40 MPH came and went in 14.7 seconds.

The Sea Ray SLX 400 OB does have a bit of a wide turn radius but it's unlikely that an operator will get as heavy-handed as we did when testing this boat. She exhibited nothing short of a solid feel as we crossed various wakes during our testing time. She will show a bit of hull slap at full speed but dialed back to cruise where she was allowed to penetrate through the waves for a much more comfortable ride. The auto-trim feature used throughout hard turns was met with no prop ventilation whatsoever. It was just a remarkably pleasurable boat to drive.


Standard power for the SLX 400 OB is the triple 300-hp Mercury Verado outboards with Joystick Piloting (Tri-300 hp / 224 kW).

Optional power includes…

  • Triple 350-hp Mercury Verado® Outboards with Joystick Piloting — Black (Tri-350 hp / 261 kW)
  • Triple 350-hp Mercury Verado® Outboards with Joystick Piloting — White (Tri-350 hp / 261 kW)
  • Triple 400-hp Mercury Verado® Supercharged 2.6L L6 Outboards with Joystick Piloting
  • Triple Mercury Racing with Joystick Piloting Carbon Fiber Accents (SLX-R Package Only) — White (Tri-400 hp / 298 kW) 450R 4.6L V8 Outboards – Cold Fusion White with (Tri-450 hp / 336 kW)

Boat Inspection


The aft-facing seating at the stern is plenty large enough at 8’ (2.44 m) across.  Fore and aft, we measured 34” (86.36 cm) inches, providing plenty of room for sitting, relaxing and lounging about.  The portside seat lifts and beneath that is cavernous storage that can hold longboards, skis, wakeboards and even stand-up paddleboards.  There's an inflator for water toys and a pole stored in this compartment that is used to support the pull-out shower wand creating an actual stand-up transom shower. 

Sea Ray SLX 400 OB Swim Platform

Even with the outboard power, the spaciousness of the swim platform is not sacrificed. At its narrowest, it comes out 16” (40.64 cm) from the transom.

Sea Ray SLX 400 OB Aft-Facing Seating

The aft-facing seats can easily accommodate five. 

Sea Ray SLX 400 OB Port Seat Storage

Under the port seat is huge storage that continues under the cockpit seating.

Sea Ray SLX 400 OB Transom Shower

A pole comes out of storage to support the pull-out shower creating a stand-up transom shower.

Power Terrace

At the side of the cockpit walkthrough in the Sea Ray SLX 400 OB, the bulkhead is all teak.  At the touch of a button, we can lower the whole section to create a starboard side patio.  Additionally, releasing a latch allows for swinging the adjacent seatback to the side providing an excellent place to face the platform and watch the kids swim.  When lowered, the terrace adds 3’ (.91 m) to the boat's beam. 

Sea Ray SLX 400 OB Power Terrace

The power terrace creates an expanding play area. 

Sea Ray SLX 400 OB Seatback

Notice how the adjacent seatback swivels around to add more seating that faces the terrace. 


At the 18” (45.72 cm) wide walkthrough, there are steps leading up to the teak caprail for boarding from a fixed pier and there’s self-draining storage underneath the steps.   Right alongside, there are switches for the terrace and the hatch for getting into the massive storage where the engine compartment used to be.   

Sea Ray SLX 400 OB Cockpit

Steps to the side of the cockpit facilitate boarding from a fixed pier. 

Gatherings are clearly the theme of the Sea Ray SLX 400 OB cockpit as there’s so much seating.  It starts with L-shaped seating around the port side and across the stern.  There’s storage underneath the aft seat to hold a carry-on cooler.  Additional storage continues underneath the seats and behind the port side seatback.  All of this wraps around an expandable solid wood table on a fixed pedestal. 

To starboard, opposing seating takes up the forward corner.  Alongside are dual electric grills and a stainless-steel single basin sink.  Underneath are dual refrigerators.  Ahead and to port, the 39” (99.06 cm) wide observer’s seat with a flip-up bolster can swing around with the release latch on the side and join the crowd.

Sea Ray SLX 400 OB Cockpit Seating

L-shaped seating at the cockpit surrounds a solid wood table.  Seating includes dedicated storage for a carry-on cooler. 

Sea Ray SLX 400 OB Grill

Dual electric grills are to the starboard side.  Fully aft is a single basin sink.

Sea Ray SLX 400 OB Refrigerators

Dual refrigerators are under the electric grills.  One can be swapped out for a wine chiller. 

Sea Ray SLX 400 OB Observer's Seat

By swinging the observer’s seat around, we create voluminous seating. 

All of this is protected by the standard hardtop 6’7” (2.01 m) off the deck.  It includes an optional sunshade 66” x 50” (167.64 cm x 127 cm) and it opens manually.  There's also an optional SureSHADE extendable awning at the aft end adding 7’ (2.13 m) of shade to the trailing edge and carrying it all the way back to the aft end of the seats.


The gatherings continue at the bow that are accessed through a 22” (55.88 cm) walkthrough windshield, which narrows down to 18” (45.72 cm) at its forward-most point.  The bow features three-across forward-facing seating.  Each seat includes flip-down armrests. There’s additional seating up forward flanking a solid wood expandable table. This, along with the pedestal, gets dedicated storage in the deck hatch just underneath.  To the starboard side is a Fusion stereo with connectivity, more beverage holders and an armrest.   

Sea Ray SLX 400 OB Bow

The bow includes three-across seating with flip armrests.  Notice the grab rail behind the seats.  We’d move that to the top of the caprail for easier reach.  Fully forward is seating that flanks a solid wood pedestal table. 

Cabin Class

The Sea Ray SLX 400 OB can entertain at least 15 people and can overnight four. The cabin is accessed from a sliding center-mounted door.  Inside is 6’3” (1.91 m) of overhead clearance. 

Wraparound seating is forward, surrounding an expandable pedestal table that can also be lowered to a two-person berth.  There’s storage under the portside seat back and under the starboard side seat base.  A 32” (81.28 cm) TV is on the port bulkhead. 

Sea Ray SLX 400 OB Cabin

The cabin includes convertible seating and a galley to port. 

Sea Ray SLX 400 OB Mid-Cabin

Two can be comfortable in the mid-cabin. 

The galley includes the usual features of a refrigerator, microwave and storage.  Behind, there’s a mid-cabin that will sleep another two people.  There’s storage to both sides, plenty of interior room and overhead clearance.

A wet head is to starboard and features a hullside window, storage behind a mirror just above a vessel sink mounted on a Corian counter and more storage below.   

Operational Features Inspection

Under the aft-facing seat to port, that massive storage also includes all the shore power connections, the city water inlet, phone and TV connections and a freshwater washdown. Of course, the most significant aspect of this area is the outboard power.  We can go with the 300-horsepower of our test boat or up to 400 Racing engines, all from Mercury.  That said, this is the new V-technology from Mercury so there’s a lot of torque, a lot of power, bigger alternators and they run a lot quieter. 

Sea Ray SLX 400 OB Utilities

Under the stern seating are all the utility connections. 

Inside the cockpit, we electrically lift what was the engine hatch.  Inside is an optional Seakeeper 3 and I noticed that the stringers are already built to accommodate it.   To the porthand side are the house and engine start batteries and the generator.  On the starboard side are the hydraulic components for the terrace. 

Sea Ray SLX 400 OB Engine Hatch

What was formerly the engine compartment is now housing the Seakeeper 3 and all the main mechanical components. 


The Sea Ray SLX 400 OB has outdone itself with one of the nicest helms I've seen in class. It features a soft-touch dash over dual Simrad displays. They include the connectivity to the Naviop system for controlling the electrical switching throughout the boat.  It includes preset settings for all the lighting, all of the battery readouts, tank levels and so much more.   

Sea Ray SLX 400 OB Helm

Sea Ray has made an elegant helm by using Simrad flush mount NSO displays. 

Sea Ray SLX 400 OB Remote

One of the things we appreciate is when a builder correctly puts the remote for the displays to the side of the helm seat where it can be reached.  It also helps to have the joystick behind the engine controls. 

Now, these are the new Simrad NSS evo 3S series displays.   Not only do they have a tide graph in the middle of the data bar, but we can also add up to six panels on the screen.  Additionally, they’re also connected to the engines giving us full readouts of the engine parameters and vessel controls such as cruise control, troll control, active trim and control of the sport exhaust.

To the right side is a sub-panel housing auto glide automatic trim tab system, the digital throttle and shifts, remote control for the Simrad displays, the JPS joystick for functionality at the dock and a Simrad VHF. 

There are dual helm seats, each one 24” (60.96 cm) across. They include flip-up bolsters and adjust fore and aft.

Sea Ray SLX 400 OB Anchor

The ground tackle is concealed under dual hatches. 

Sea Ray SLX 400 OB Electrical Panel

The vessel’s main electrical panel is behind a seatback in the cabin. 

Fathom ePower

We already talked about the fact that Sea Ray SLX 400 OB has a generator for running the electrical systems, but there's also a very cool system called the Fathom ePower that gives 22-kilowatt hours of lithium-ion batteries that will power all the electrical on the boat.   As it starts wearing the batteries down, it starts shedding nonessential loads when it gets to within 5%.  Plus, it will all interface with the Simrad displays so there’s an accurate readout of exactly how much power is left in the system.  The batteries can recharge from either the alternators on the engines, the generator or shore power.   

Options to Consider

Aside from individual options, there are three option packages for the Sea Ray SLX 400 OB. 

The SLX-R package on the Sea Ray SLX 400 OB includes:

  • Triple Mercury Racing 450R outboard engines
  • Badging, SLX-R
  • Dynamic Running Surface
  • Hardtop — black painted
  • Helm with true carbon fiber accent panels
  • Hull paint — Shadow Metallic Lighting, accent — red
  • Lighting, underwater — red
  • Simrad NSO evo3 16" (40.64 cm) dual displays
  • Steering wheel, upgraded
  • Stereo upgrade, premier (speaker/subwoofer/amp)
  • Upholstery — Stone with red accent stitching

The Design Package on the Sea Ray SLX 400 OB includes:

  • Dynamic Running Surface
  • Hardtop — black painted
  • Helm with true carbon fiber accent panels
  • Hull paint — Shadow Metallic
  • Lighting, accent — red
  • Lighting, underwater — red
  • Dual Simrad NSO evo3 16" (40.64 cm) displays
  • Steering wheel — upgraded
  • Stereo upgrade, premier (speaker/subwoofer/amp)
  • Upholstery — Stone with red accent stitching

The Elite Plus Package includes:

  • Anchor — stainless steel
  • Dynamic Running Surface
  • Fender clips
  • Hardtop, fiberglass with opening canvas section
  • Lighting, underwater (thru-hull) Lighting package, LED
  • Stereo upgrade, premier (speaker/subwoofer/amp)
  • Sunshade, extended

Additional options include:

  • Canvas Package for Fiberglass Hardtop 
  • Cockpit Cover w/ Tonneau Cover 
  • Extended Sunshade for Hardtop (SureShade)
  • Marine Midnight Blue Canvas 
  • Opening Canvas for Hardtop 
  • Sunshade, Bow Seating 
  • Toast Tweed Canvas
  • Fathom e-Power System (Includes: Monitoring System w/User Interface, Inverters, 4 Marine Grade Lithium-Ion Batteries) Replaces Generator Option
  • Flat Screen TV w/ DVD Player — Cockpit 
  • Flat Screen TV w/ DVD Player — Mid-Cabin 
  • Flat Screen TV w/ DVD Player — V-Berth 
  • Marine Weather 
  • Premier Audio Upgrade — Combined Cabin & Cockpit (Includes: SRX 400 in Cabin, (6) Pair of 6.5" (16.51 cm) Signature Series Speakers & 10" (25.4 cm) Signature Series Subwoofer)
  • Simrad Halo 24 Radar 
  • Simrad RS40 VHF Radio w/ Antenna 
  • SiriusXM Satellite Receiver (N/A outside North America) 
  • Air Compressor for Water Toys 
  • All Chain Windlass w/ Galvanized Anchor 
  • Blue LED Lighting Package 
  • Docking Lights 
  • Dual 12V Refrigerators in Cockpit Wet Bar 
  • Enhanced Storage option w/ two drawers for Cockpit Wet Bar (takes place of wine cooler option & second refrigerator option)
  • Fender Clips (6) Quick Connect 
  • Flagpole w/ Base & US Flag
  • Gray Water System 
  • Grill, Dual Electric — 120v/60 
  • Gyroscopic Stabilizer (Seakeeper 3) 
  • Inverter — 12v to 120v/60 Cycle (REQUIRES TV) 
  • Macerator w/ Seacock Interlock System 
  • OEM Battery Installation (Includes: 6 Group 31 AGM Batteries) 
  • Remote Controlled 5" (12.7 cm) Spotlight 
  • Single Electric Grill in Cockpit — 120V/60 
  • Stainless Steel Anchor
  • Teak Bow Table w/Dedicated Storage 
  • Thru-Hull Under Water Blue LED Lights 
  • Thru-Hull Under Water White LED Lights 
  • VacuFlush Head System w/ Direct Overboard Discharge (Int'l) 
  • White LED Lighting Package
  • Wine Cooler 


Change is a good thing and by making some fundamental improvements to the original SLX 400, Sea Ray has unquestionably made a good boat even better.  She appeals to families and executives looking to entertain clients equally well.