Harris FloteBote Grand Mariner SL 250 (2010-)
(w/ 1 x 225-hp Mercury Verado 4-stroke)

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Grand Mariner SL 250 (2010-)
Harris FloteBote Grand Mariner SL 250 (2010-) Test Video

It’s hard to have a bad day on the water when you’re inviting 13 of your friends onboard for a day of fun in the sun. Throwing in a touch of luxury makes it that much better. With the Harris Flotebote Grand Mariner SL 250, you’ll be entertaining in style and luxury that will have your guests lining up to be on the next cruise. Her amenities make for easy relaxing while the captain will appreciate the handling qualities and safety features built into the layout.

Key Features

  • Bimini, 11'6" (1.25" frame w. SST quick release)
  • Carpet, Imperial Two-Tone 32oz
  • Flooring, TPO for ext swim platform
  • Glovebox, lockable
  • Lighting, courtesy
  • Seat, helm, Ultra Lux
  • Ski tow bar, SST
  • Skin kit, aluminum (3/4 from stern)
  • Stereo, Sony Gold (incl CD player, 6 spkrs, USB port)
  • Sunlounge, oversize stern with flip-flop backrest
  • Swim platform, extended (incl rear TPO)
  • Table, aft with molded drink holders
  • Trailer protection clips
  • Windscreen, removable


Harris FloteBote Grand Mariner SL 250 (2010-) Specifications
Length Overall 26' 4''
Dry Weight 3,200 lbs.
1,451 kg
Beam 8' 6''
2.59 m
Tested Weight N/A
Draft 21''
0.53 m
Weight Capacity N/A
Draft Up N/A Person Capacity N/A
Draft Down N/A Fuel Capacity 45 gal.
170 L
Air Draft N/A Water Capacity none
Deadrise/Transom N/A Length on Trailer N/A
Max Headroom open Height on Trailer N/A
Bridge Clearance 62''
1.58 m
Trailer Weight N/A
Total Package Weight (Trailer,Boat & Engine) N/A
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.

Engine Options

Harris FloteBote Grand Mariner SL 250 (2010-) Engine options
Std. Power Not Available
Tested Power 1 x 225-hp Mercury Verado 4-stroke
Opt. Power 1 x 150-hp Mercury Verado
1 x 175-hp Mercury Verado
1 x 200-hp Mercury Verado
1 x 225-hp Mercury Verado
1 x 300-hp Mercury Verado

Harris FloteBote Grand Mariner SL 250 (2010-) Line Drawing


Harris FloteBote Grand Mariner SL 250 (2010-) Captain's Report

Harris Flotebote Grand Mariner SL 250

With its sweeping curves to the side fences, and a grand interior, it’s hard to ignore the level of luxury in the Grand Mariner SL 250.

Captain’s Report

The Grand Mariner series is Harris FloteBote’s upscale pontoon line. Not only are they very comfortable, but the options list is long enough to allow you to customize your 'toon to your specific uses. The difference between the SL and the SEL versions is the power. SEL’s are sterndrive, while the SL’s are outboard powered. You won’t save room on deck by switching to the outboard version. The seating that lies above and around the sterndrive’s engine box over the center pontoon will still be there, but raising the former engine hatch will expose storage underneath in the outboard version. For today’s test, we were assigned the SL 250 powered by a Mercury 225 Verado 4-stroke. First, more on the boat.

Features Galore

For starters, Harris FloteBote set out to make sure you could store whatever you needed to bring aboard, and did it with the “a place for everything and everything in its place” mentality. And in the optional entertainment center (add $1,200), Harris also created “smart storage” where you actually have dividers to insert in various places to create storage sections depending on what you have to store, be it dry towels, wet towels or silverware.

Harris Flotebote Grand Mariner SL 250

With inserts, you can create storage bins to suit your needs. Note the stainless steel drawer sliders.

The Grand Mariner SL 250 is also easy to clean. The textures of the seats are such that no moisture will collect in corners or low spots, and the material is Torino vinyl with Prefixx built in to ease removal of marks and stains. Typically, when a cleaner such as 409 is used on vinyl, it strips the protectant off and then every wet bathing suit leaves a color stain. Prefixx allows you to use even nail polish remover without doing harm to the seats, and even accidently writing on the seat with a Sharpie is no problem.

A 25-qt (23.7 L) transom cooler is standard, as well as the LED docking lights, courtesy lighting, a Sony Gold stereo, and Bimini just to name a few.

The side fences are built ¼” (6.35 mm) off the deck, so you won’t get beach sand collecting in the corners, and rain or hose water will run right out.

Harris Flotebote Grand Mariner SL 250

Lighted toggle switches with circuit breakers right underneath. The keypad is for a keyless starting system. You can program a code into it so that you’re the only one who can start your boat.

Harris Flotebote Grand Mariner SL 250

The aft entertainment center is the perfect place to spend the afternoon at anchor. Under the left seat is a cooler, under the right is a storage space for wet gear. Those aft speakers get a separate aft mounted volume control.

Harris Flotebote Grand Mariner SL 250

The helm is on a raised platform to aid with visibility when passengers are seated in front. We’d love to see the engine controls mounted on the horizontal for better controllability. Inside the left circular cubby is a 12v power supply outlet.


Pontoon boats are made with plywood decks, and wood rots... right? Not so fast. Harris FloteBote adds a few touches to their build process to fend off that problem. Four touches to be exact: First, they add protective tape to the aluminum cross members, so the wood is not resting right on top. Next, the plywood is joined by tongue and groove joints. This prevents water seepage into the joints and vulnerable end-grain. But water is tricky, and maybe some will still sneak past the joints. So Harris FloteBote adds sealant to the joints to completely protect them. Finally, they add sealant to the tops and bottoms of the seams. Now it’s watertight and when combined with the marine-grade pressure-treated wood, the result is a deck with a limited lifetime warranty.

The pontoons are constructed in-house with baffles to create separate chambers in each tube. All welds are pressure tested for integrity. In effect, you could hole a pontoon and the boat will still float due to the separate chambers. A flange is welded to the top, to mount the deck onto, and this distributes the load through the length of the tube to eliminate flexing when hitting waves.

Harris Flotebote Grand Mariner SL 250

The standard P-3 package adds a ventilated-stepped tube to break the bond between the water surface and the tube, giving better performance.


Accommodations for safety are evident everywhere. The gates all have full-length stops that can hold 400lbs of pressure, so falling into one from a boat wake will not mean falling through. The re-boarding ladder is custom built, not off the shelf. It’s 20” (51 cm) wide with 2.5” (6.4 cm) foot treads, and made of heavy-duty stainless steel. You typically see these ladders with three steps that are difficult to step onto. This ladder has four steps and it’s angled out so it’s easier to find underwater with your foot. Decks run out past the ends of the tubes, non-skid is everywhere you would step (even on top of the nav lights)… the list goes on and on.


Having options means you can fine tune your ‘toon to suit your needs and desires. This is much better than having a “one size fits all” boat, and at Harris FloteBote the options are diverse and varied. The most important questions are… how far do you want your luxury to go and how much do you want to spend?

While it’s nice to have the standard Bimini, hydraulically operated is easier (add $2,990). Deck extensions are available in 1’ (add $340), 2’ (add $670), and 4’ (add $1,340) lengths. Tired of dock lines lying around the boat? Retractable lines are for you (add $920). Since we’re partying onboard we’ll need the entertainment center with fridge (add $2,250). If you’re not a fan of carpet you can add the look of faux teak to the whole boat (add $7,980) or choose to teak just the bow (add $180) or the swim platform (add $1,980). Of course there are individual seating choices for the bow and helm positions. It’s all a matter of taste and whatever yours is, Harris FloteBote has you covered.

Harris Flotebote Grand Mariner SL 250

Handling Characteristics

We tested the SL 250 on a gusty 20-25 mph day with solid chop on a Minnesota lake. Not ideal conditions for testing a tri-toon, but it’s days like this that show the sins. For starters, when heading into the chop, we discovered that the water hitting the PIII performance center-toon was having an effect of pushing against the boat. The resulting feeling was like pumping the brakes in your car and lurching you forward with every wave.

The side-toons threw water off via the spray rails, and being spray, the wind would catch it and blow it onto the boat. In beam and following seas the tubes were long enough to stretch across the chop and we got a smooth ride. Remember however, this was in a heavy chop that would not be the kind of day you would be likely to take out friends.

Stopping the boat had the wind catching the fences immediately and turning us beam to. Not uncomfortable, but it did show that if you have any plans of drift fishing across the lake, then this is your boat. You’ll be able to utilize the full length as you drift. All in all, it was a positive test as we got a good feel for how the boat would react in rough conditions.

Harris Flotebote Grand Mariner SL 250

Calming Down

We then went to a remote hidey-hole to find calmer water and got a taste of how the SL 250 should really feel in normal conditions, and it was very comfortable. The 250 had a solid feel that belied its relatively light weight. Acceleration was crisp and you felt yourself moving forward with the boat, rather than being thrown back as the boat drove forward.

Hard turns were met with a small bit of prop ventilation, so slow down before turning hard, or don’t turn as hard. This is characteristic of pontoon boats, not just this model, so no points deducted. The best word I can use to describe the feel is solid.

Close Quarters

When docking, I used the old V-hull trick of approaching just off the dock and letting the hull’s momentum slide me into the dock. Don’t try this with a tri-toon… there is no slide. When you dock this boat, drive it up to the dock, slowly, coming close enough to step off and tie the lines. If you think it’ll keep drifting over when you reverse to slow, all you’ll get is slowing or stopping right where you are. The wind or tide may move you, but momentum will not, because tri-toons carry very little way at slow speeds.

Backing had a different feel too. Instead of the stern backing one way and the bow swinging off the other, I found the bow to slide in the same direction that I was steering the stern. These two observations make docking simple. Just drive the boat over to the dock, whether forward or reverse, and the rest of the boat will arrive there too. Simple enough.

Harris Flotebote Grand Mariner SL 250

Performance Numbers

Our test boat was powered by an optional 225-hp Mercury Verado 4-stroke. Top speed was 35.9 turning 5600 rpms. I think she could do better with a different prop. Our top rpms were 5600 on an engine rated for 6200, so it appears the prop was over-pitched.

Pulled back to a more sedate 3000 rpm we were cruising at 17.1 mph. I tend to go by feel and find a comfortable speed without looking at the gauges until after that speed is set. Therefore, my hand settled the throttle at around 4000 rpm for a decent comfort level and a speed of around 24.5 mph. That will also yield a speed that your guests will find comfortable as well. Being a tri-toon, there is very little bow rise when accelerating, so she had a short time to plane of only 3.5 seconds. Time to 30 mph was 6.4 seconds.

The base boat is powered by a 150-hp Mercury Verado and has an MSRP of $51,800.00. An upgrade to a middle of the road 225-hp Verado, that we tested with, will add $7,930. If you want to move to the top of the food chain, the Mercury 300 Verado will add $11,700 over base. Naturally street prices will differ, so don’t be afraid to wheel and deal. You’ll end up with a great boat and a boatload of memories.

Harris Flotebote Grand Mariner SL 250


There are few boats on the market that foot-for-foot, dollar-for-dollar provide as many watersports opportunities and entertaining pleasure than does a tri-toon. You can waterski behind it, go tubing, swimming, scuba diving or snorkeling, cruising, camping out, and of course do first class entertaining. Be sure to match the boat with the body of water you plan to use it on. And make sure that you customize the boat to take care of the needs of every member of your family.

The cost of entry into this business is low. For that reason, there are many tri-toons on the market and most of them are made by local builders only selling near the factory. Because these regional builders generally sell for slightly less, it is easy for a consumer to make a mistake. All tri-toons are not the same, and all 'toon builders are not the same. You want a boat made of the best materials so that it will still look new when you go to sell it down the road. Low-priced, locally made units are less likely to keep their new look, hold up, and be in business if you need warranty work or parts later. If you have seen old weathered 'toons with delaminating decks in a boatyard or behind someone's summer cottage, you know what I mean.

Harris FloteBote is one of the four or five premier companies making pontoon boats. It is owned by the Brunswick Corporation which means the company has the infrastructure, corporate governance and customer service culture to both build good boats and keep its customers happy.

Harris FloteBote Grand Mariner SL 250 (2010-) Test Result Highlights

  • Top speed for the Harris FloteBote Grand Mariner SL 250 (2010-) is 35.9 mph (57.8 kph), burning gallons per hour (gph) or N/A liters per hour (lph).
  • Best cruise for the Harris FloteBote Grand Mariner SL 250 (2010-) is 20.6 mph (33.2 kph), and the boat gets miles per gallon (mpg) or N/A kilometers per liter (kpl), giving the boat a cruising range of miles (N/A kilometers).
  • Tested power is 1 x 225-hp Mercury Verado 4-stroke.
For complete test results including fuel consumption, range and sound levels
go to our Test Results section.

Standard and Optional Equipment

Harris FloteBote Grand Mariner SL 250 (2010-) Standard and Optional Equipment
Marine Electronics
Fishfinder Optional
GPS/Chart Optional
CD Stereo Standard
Head: Portable Optional
Exterior Features
Carpet: Cockpit Standard
Outlet: 12-Volt Acc Standard
Swim Ladder Standard
Swim Platform Standard
Tower: Watersports Optional
Wet bar Optional
Bimini Top Standard

Standard = Standard Optional = Optional

Harris FloteBote Grand Mariner SL 250 (2010-) Warranty

Harris FloteBote Grand Mariner SL 250 (2010-) Warranty Information
Warranties change from time to time. While BoatTEST.com has tried to ensure the most up-to-date warranty offered by each builder, it does not guarantee the accuracies of the information presented below. Please check with the boat builder or your local dealer before you buy any boat.
NMMA Certification Yes

Harris FloteBote Grand Mariner SL 250 (2010-) Price

Harris FloteBote Grand Mariner SL 250 (2010-) Price
Pricing Range $59,730.00
Price as Tested $62,540.00
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 numbers for this model are archived.