2022 Harris Grand Mariner 250 SL

The Grand Mariner 250 SL is responsive and nimble.

Harris always provides above-the-bar pontoon boats, and this year’s Grand Mariner 250 SL did it again. Fitted with a Mercury Verado 300 FourStroke outboard, it romped from a dead idle to 30 mph in a cat-quick 5.8 seconds and topped out at a tick under 48 mph. At its best cruise speed of 17.2 mph at 3,000 rpm, the 300 Merc consumed 5.1 gph for a 3.4 mpg gait.  

Grand Mariner 250 SL on the lake
The Grand Mariner 250 SL pops and flies when the Mercury 300 is trimmed out. Bill Doster

It’s a driver’s boat too, responsive and nimble considering its near-28-foot length. Three 25-inch pontoons help it along, featuring the Performance Level III package, with in-floor storage, lifting stakes on all three tubes, and a wind-cheating skin cover underdeck. It’s responsive to engine trim, and pops and flies when the Mercury 300 is trimmed out, like driving a high-performance hull. 

Grand Mariner 250 SL helm
There’s a standard Simrad GO7 in the dash. Bill Doster

Harris focuses on the big picture for interior layout, and the Grand Mariner features a sleek fiberglass perimeter bow trimmed in navy gelcoat, with built-in lighting pods for navigation and docking; this transitions midway back to a traditional aluminum perimeter. 


Bow seating features a full-length starboard lounge extending back to the driver’s console, and a shorter portside lounge. The upholstery is luxurious, with nifty pockets housing cup holders and phone chargers. The JL Audio Diamond package has eight speakers and a subwoofer; two speakers can be added to the arch. 

Grand Mariner 250 SL bow seating
Bow seating features a full-length starboard lounge. Bill Doster

A raised helm station is standard, with a standard Simrad GO7 in the dash. The boat’s key fob controls the lights, stereo and arch. Standard C-Zone switching features a Harris-specific application for all boat controls and engine information.  

The aft seating features a huge lounge platform three-quarters-wide across the stern providing access to the aft deck via the starboard side. A multiposition reversible backrest combined with adjustable footrest cushions provides nearly infinite configurations for lounging, with a built-in cooler underneath. 

Grand Mariner 250 SL cockpit
Aft seating features a huge lounge platform three-quarters-wide across the stern. Bill Doster

The extended aft deck features a stainless-steel flip-down swim seat and an auto-retracting boarding ladder. Stainless-steel fender holders are integrated into the perimeter fencing—a nice touch. 

The electric folding tower is equipped with JL Audio speakers.

High Points

  • JL Audio package makes for a sound system that thumps loud and crisp. 
  • Electric folding tower features covered hinges. 
  • It’s a party platform with a watersports purpose, an all-around high-end performer. 

How We Tested

  • Engine: Mercury Verado 300 FourStroke 300 hp
  • Drive/Prop: Outboard/Mercury Enertia Eco 16″ x 17″ 3-blade stainless steel
  • Gear Ratio: 1.75:1 Fuel Load: 40 gal. Crew Weight: 250 lb.

Pricing and Specs

Price: $155,017
LOA: 27’11”
Beam: 8’6″
Draft: NA
Dry Weight: 4,045 lb.
Seat/Weight Capacity: 13/2,189 lb.
Fuel Capacity: 63 gal.

Harris Pontoon Boats – Fort Wayne, Indiana; 260-432-4555;