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](https://www.boatingmag.com/uploads/2021/12/BTGBG22_PON_Harris-Grand-Mariner-250-SL_01-1024x682.jpg)
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](https://www.boatingmag.com/uploads/2021/12/BTGBG22_PON_Harris-Grand-Mariner-250-SL_11-1024x682.jpg)
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](https://www.boatingmag.com/uploads/2021/12/BTGBG22_PON_Harris-Grand-Mariner-250-SL_07-1024x682.jpg)
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](https://www.boatingmag.com/uploads/2021/12/BTGBG22_PON_Harris-Grand-Mariner-250-SL_17-1024x682.jpg)
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.
![](https://www.boatingmag.com/uploads/2021/12/BTGBG22_PON_Harris-Grand-Mariner-250-SL_19-1024x682.jpg)
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 |
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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; harrisboats.com