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Grady-White Marlin 300 (2017-)

2 x 300-hp Yamaha V6 4.2L

Brief Summary

The Grady-White Marlin 300 is a fully-equipped blue-water fishing vessel and she can accommodate up to four people for overnight excursions. The walk-around design adds safety for fishing far offshore in rough conditions, while the aft cockpit has plenty of space for trolling as well as for after-hours entertaining. Her 282-gallon (1,067 L) fuel capacity gives her a range of about 390 statute miles at 27.6 mph with the twin 300-hp Yamaha four-strokes provided for our tests.

Key Features

  • Aft double berth and forward vee berth
  • Port side galley with sink, light and Corian cutting board
  • Enclosed head area w/sink, shower, lamp & VacuFlush® marine head w/freshwater supply, 10-gallon (38 l) holding tank, overboard discharge & deck pump-out
  • Battery charger system
  • Recessed cockpit freshwater shower
  • 290-quart insultated fishbox with light and overboard drain
  • Stereo system with AM/FM tuner, MP3 auxiliary audio connections/amplifier, Bluetooth, remote control and fold-down storage; speakers w/ LED lights
  • 32-gallon port insulated raw water livewell with light, full column distribution inlet and ob drain

Test Results

600 3 2.6 1.5 2.1 1.8 525 456.6 67
1000 6.1 5.3 2.6 2.4 2.1 602 523.6 69
1500 8.1 7 4 2.1 1.8 520 452.6 72
2000 9.6 8.3 6.6 1.4 1.3 367 319.3 75
2500 12.7 11 10 1.3 1.1 322 280.3 82
3000 19.5 17 13.4 1.5 1.3 371 322.4 84
3500 27.6 24 18 1.5 1.3 390 338.7 85
4000 32.5 28.3 23.7 1.4 1.2 349 303.3 85
4500 37.5 32.6 30.8 1.2 1.1 309 268.7 87
5000 42.2 36.7 37.8 1.1 1 284 246.7 88
5500 47.3 41.1 47.4 1 0.9 253 220.2 91
5900 50 43.4 52.7 0.9 0.8 241 209.4 93


Length Overall 30' 6'' / 9.30 m
Beam 10' 7''
3.23 m
Dry Weight 8,221 lbs.
3,729 kg
Tested Weight 10,615 lbs.
4,815 kg
Draft 23''
0.58 m
Deadrise/Transom 19.5-deg (SeaV2® progression)
Max Headroom N/A
Bridge Clearance 9' 9''
2.97 m
Fuel Capacity 282 gal.
1,067 L
Water Capacity 32 gal.
121 L
Total Weight 10,615 lbs.
4,815 kg


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Acceleration Times & Conditions

Time to Plane 3.3 sec.
0 to 30 6.9 sec.
Ratio 1.75:1
Props 15 1/2" x 17 SWS II SDS
Load 3 persons, 2/5 fuel, no water, 50 lbs. of gear
Climate 78.8 deg., 75 humid.; wind: 5-10 mph; seas: calm

Engine Options

Tested Engine 2 x 300-hp Yamaha V6 4.2L
Std. Power Not Available
Opt. Power 2 x 250-hp Yamaha 4-stroke
2 x 300-hp Yamaha 4-stroke
2 x 350-hp Yamaha 4-stroke

Captain's Report

The Marlin 300 has an LOA of 30’6” (9.30 m), a beam of 10’7” (3.23 m), and can sleep as many as four.


The Marlin 300’s SeaV2® hull and overall design make it an offshore saltwater fishing vessel first and foremost. The 30’6” (9.30 m) LOA and cabin below deck are a marriage of practicality and convenience. Perhaps the most important thing about the Marlin 300 is that it is a lot more comfortable – dryer and safer – for extended trips far offshore for bluewater fishing. Because she is not an open boat, when the sea gets rough, her closed foredeck and protected bridge and cockpit make her a welcome alternative to any center console on the market.

The addition of Strataglass between the windshield and the hardtop allows the bridge to be buttoned up for a cozy ride home when the weather turns foul. In addition, the square footage in her cockpit is greater than what is found in most center consoles her size between the lead post or bait-prep station and the transom.

The added advantage of the design is that she has an enclosed head with sink and shower, a full galley, and a U-shaped seating area with a convertible table for dining which can be made into a double berth. Another berth is amidships. For this reason, the Marlin 300 can also be used for cruising and even short weekend over-nighting.

A “Walk Around”. The Marlin 300 is the largest boat in Grady-White’s “Walk Around” series, but frankly, we think of her more as more of an fishing fishboat. “Walk Around” refers to the side decks which are recessed to provide secure footing when working a fish around the boat. We think these side decks are an excellent compromise between an express and a center console. For all of these reasons we find that she provides a lot more utility than the ubiquitous center console.

The layout of the Marlin 300, with the main deck view overlaid on the cabin.

Major Features

  • SeaV2 Hull Design. The hull was designed by C. Raymond Hunt and Associates which knows as much about designing a deep-V hull as any firm on the planet. Her high deadrise forward widens to a moderate deep-V aft to combine stability with riding comfort.
  • Below Deck Features. The Marlin 300 has two berths, galley, full head with a shower, dining space, storage, with optional air conditioning, and entertainment platforms.
  • Aft Fish Box. Along the transom is the 300’s 290-quart (275 L) aft insulated fish box. It comes standard with a light and overboard drainage.

Features Inspection

Stern/ Swim Platform

Grady-White Marlin 300 ladder

A view of the sturdy transom door with positive-locking 316-grade stainless steel latch.

The stern of the Marlin 300 is nearly all engine with a stainless steel re-boarding ladder on the starboard side. The ladder is molded-into the fiberglass platform, and just below it begins the 300’s rub rail, which circles the entire boat and is made of high-quality PVC with a stainless steel insert.

Just forward of the re-boarding ladder is the transom door. The stout door is made of fiberglass with a heavy-duty stainless steel latch on the inside just below the cockpit bolster that extends to include the transom door. The door opens out, which we prefer so it does not restrict cockpit space.


A view of the cockpit from the aft end of the boat displaying a well-defined fishing space with cockpit bolsters lining it.

The cockpit on the Marlin 300 is the primary fishing space, and is broken up forward by two steps up to the helm deck and access to the cabin below. A bolster wraps around the cockpit with four dedicated rod holders mounted into the reinforced gunwales. Rod racks are under both gunwales. Just below these are toe rails that can be used when hauling in the big one. On the hardtop legs, two to each side, are stainless steel rocket launchers.

Along the transom is the freshwater cockpit shower. The majority of the transom panel, however, is taken up by the 300’s 290-quart (274 L) fish box, which has LED lights and drains overboard. On the port end of the transom is a lift-out storage bin under a fixed cutting board. Under the bin is access to two battery banks with four batteries.

The aft seating in the cockpit, in its folded-down position. Note the fresh and raw water washdowns under the cockpit bolster in the background.

There is a fold-down bench seat facing forward on the transom as well with marine-grade weather-resistant upholstery. Below the seat is an access hatch to levered seacocks and the 5 kW generator.

The levered seacocks are a very good idea and something that we only rarely see. They enable the seacock to be turned off quickly in an emergency without having to fish around for a long reach to the thru-hull. More builders should use this concept when not able to put the seacock within easy reach.

Grady-White Marlin 300

The rigging station in the cockpit to starboard. Note the sink and lockable tackle storage below.

Grady-White Marlin 300 livewell

The cockpit livewell, which sits to port, just abaft the companion seat.

Cockpit Details. Forward the rod holders in the gunwales are fiberglass steps up to the side decks on each side. Adjacent to the steps up to the helm on the centerline on each side are two stations: to port is a 32 gallon (121 L) insulated raw water livewell with a light, full column distribution inlet, and overboard drain; to starboard is a rigging station with a freshwater sink, insulated bait box, and lockable drawers. For both, cushions can be easily installed just on top, creating additional cockpit seating space.

The lighted cockpit bolsters in the Marlin 300, with rod racks below -- 3 on each side.

Grady-White Marlin 300 fish box

A view of the aft fishbox, removable storage tub on the port side for easy battery access and battery switches. We like the handy battery switches.

Two fiberglass steps up in the center of the boat from the cockpit to the helm. The bottom step lifts up to reveal storage space below.

Helm/ Under the Hardtop

The Command Elite helm chairs, with armrests and bolsters shown in different states of articulation.

Bridge Seating. The Marlin 300 comes standard with two Deluxe II helm seats, which are both horizontally and vertically adjustable, with armrests that can flip-up and out of the way. Both helm seats have lockable storage spaces in their bases. The boat we tested had optional Command Elite seats (shown above) that are horizontally and vertically adjustable with deluxe cushioning for smoother ride. Flip up bolsters, too. We recommend this option.

Optional Companion Bench Seat. Grady-White also offers the option to eliminate the companion bridge chair and replace it on the port side with a lounge seat that has a backrest that faces forward but also wraps along the portside gunwale for versatility in a social setting.

The hardtop comes standard on the Marlin 300 and comes as a painted aluminum frame, with radio box, storage nets, spreader lights, four side mounted rod holders, outrigger plates, and drop, front and side curtains.

The helm on the Marlin 300. Note the footrest at the bottom of frame and outlet to starboard.

The helm station has a stainless steel steering wheel with throttle just to starboard on the forward flat panel. A compass divides the dash’s flat panel. Rocker switches and the standard trim tab controls are to the right.

Grady-White offers the Yamaha Helm Master EX Digital Electric Steering standard and the Helm Master EX w/ Full Maneuverability as an option on the Marlin 300.

Grady-White Marlin 300

Grady-White’s “Captain Grady” remote system monitor comes standard with the Marlin 300.

Captain Grady. One of Grady-White’s big innovations is their Captain Grady system, which works on either an iPad or iPhone or other smart devices as an app and provide operations guides, FAQs, and troubleshooting.

Forward, the windshields are ventilated tempered glass, with windshield washers and two standard windshield wipers.


The galley on the Marlin 300’s lower deck with refrigerator, microwave, stereo control panel, and overhead storage.

Access to the cabin comes via three fiberglass stairs to port of the helm station. The flooring on the 300’s lower deck are teak and holly, and immediately to port upon entry is the boat’s galley. It has a microwave, glass electric top stove, refrigerator, Corian countertop, stainless steel sink, and trash drawer. Above is storage behind sliding cabinet doors.

The midships berth on the Marlin 300 -- note the netted storage and overhead rod racks.

Midships Berth. Immediately to starboard off the access stairs, through a lowered entrance, is the aft double berth, which has netted storage on the far wall, as well as rod storage overhead.

A view of the wet head on the Marlin 300 with the shower head, storage overhead, and sink.

Opposite the galley on the starboard side is the 300’s enclosed head. It has a sink, shower, and lamp, with a VacuFlush marine head that has a 10-gallon (38 L) holding tank and pump-out.

The forward V-berth with its filler cushions installed. Note that there are storage compartments under the cushions.

A view of the storage compartments -- note the center table is not installed in this image, and can raise/ lower depending whether one is looking to eat or sleep.

Dine or Sleep. Forward below deck is a dining space that can convert to a V-berth. The “C” shaped seating section wraps around a cherry wood table and has a backrest wrapping around the entire space. The table can be adjusted down to be level with the seating, allowing the addition of a filler cushion for conversion to a berth.

Removal of the cushions in the seating section itself reveals storage cubbies below.

Overhead are two reading lights, as well as four rod storage racks to each side, which flank the opening overhead latch that has both a screen and a shade depending on desired level of natural light and fresh air.

A view of the cherry table inserted that is level with seating.


The deep footwells add welcome security when working a fish forward in a seaway.

The Marlin 300 is a walkaround cuddy cabin, and from an easy step-up in the cockpit you’re up onto the side-decks, with the 316 grade stainless steel guide rails extending all the way up to the foredeck.

On the bow, just forward the windshield, is the opening Bowmar hatch above the lower deck V-berth. This surface can also be covered with the optional cushions and converted into a seating space.

The foredeck cushions can be easily attached to create seating in the bow.

Grady-White Marlin 300 bow pulpit

The bow pulpit and roller for the Marlin 300’s anchor and windlass.

Forward the seating space is the anchor windlass, which has foot controls to port (as well as controls at the helm), and a bow pulpit that includes a roller. To the starboard side of the windlass is the anchor locker, under a hatch with a stainless steel latch.


The Marlin 300 comes with twin 300 Yamaha four-strokes.


With a pair of Yamaha V6 4.2L 300-hp engines powering our test boat, we had an estimated test weight of 10,615 lbs. (4,815 L).

Our top speed at wide open throttle was 43.4 knots.

Best cruise came at 3500 rpm where we recorded 24.0 knots, burning 18 gph (68 lph), getting 1.3 nm per gallon (4.9 LPNM) for a range of 338 nmiles with a 10% fuel reserve.

She was fast on plane – 3.0 seconds, hitting 20 mph in 3.9 seconds and 30 mph in 6.9 seconds.

Options to Consider


Check with your local Grady-White representative for a price quote.


The Grady-White Marlin 300 has passed the test of time. The builder first introduced this series over 30 years ago and they are still in the lineup -- but re-engineered and updated over the years. That is saying something as most boat models last from three to seven years before they are discontinued.

At 30’ (9.14 m) this vessel is big enough, and seaworthy enough to take from Florida down island.

The Grady-White Marlin 300 is a top-flight fishing boat, with plenty of amenities aimed at such an excursion.

  • Cabin air conditioner 8,000 BTU
  • Bow thruster
  • 19” LED HD TV with DVD player (cabin)
  • Generator -- 5 kW diesel, 12-gallon (45.4 L) fuel capacity
  • Yamaha Helm Master EX w/ Full Maneuverability
  • Outrigger kit – 15’ (4.6 m) crank outriggers hardtop mounted
  • Outrigger kit – 15’ (4.6 m) radial hardtop mounted
  • Six additional painted hardtop top mounted rod holders
  • Upgrade Helm Chair(s): Command Elite horizontally and vertically adjustable contoured helm chair with deluxe cushioning and flip-up bolster
  • Power steering
  • Cockpit freshwater shower w/hot & cold mixer
  • Underwater blue LED lighting

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