L and S Series Architecture for Bennington Boats | Comparing Cross-Member Spacing and Structural Rigidity

You’re standing at the boat show, looking at an S Series and an L Series side by side, and you can’t shake the feeling that the L Series just feels… tighter. But is that real, or is it just in your head?

Here’s the thing about choosing a Bennington pontoon boat. The S Series gets you on the water. The L Series makes you feel like you belong there. But underneath the upgraded vinyl and the extra stainless steel, there’s a structural difference that matters—especially if you plan to keep this boat for a decade or more. Let me walk you through exactly how Bennington builds these two series, where the cross-members go, and whether the extra rigidity is worth your money.

TL;DR
The structural architecture of S and L Series Benningtons shares the same foundation—both use 16-inch on-center cross-member spacing, bolted deck construction, and M-bracket systems. The real differences are in refinement, not rigidity. L Series adds features like recessed fencing, upgraded hinges, better seat construction, and more standard stainless hardware. For 99% of boaters, the S Series structure will outlast their ownership. The L Series justifies its premium through fit and finish, not stronger bones.

Key Takeaways

• Both S and L Series use 16-inch cross-member spacing—this is the industry standard for premium pontoons
• Bennington moved from 24-inch to 16-inch spacing for marketing reasons, not because 24-inch ever failed
• The M-bracket deck system is identical across all series—extruded aluminum brackets distribute weight evenly
• L Series fencing is recessed behind rails for protection against dock rash
• The structural warranty is the same—lifetime on structure and decking for both series

The Cross-Member Question: What the Spacing Actually Means

Let’s start with the part you can’t see. Under the deck, running from port to starboard, are the cross-members. These aluminum channels support the deck and transfer weight down to the pontoon tubes. The distance between them—the spacing—determines how much flex the deck has when you walk on it.

The industry standard used to be 24 inches on center. That meant a cross-member every two feet. Then a competitor started bragging about 16-inch spacing. Bennington followed suit.

But here’s the part that might surprise you. A Bennington factory representative who handled warranty claims for years said this: “In all the time they used 24” OC, they never had a claim and they performed exactly the same” .

That’s right. The move to 16-inch spacing wasn’t because 24-inch was failing. It was because customers wanted what the other guy had.

So both S and L Series use 16-inch spacing today. If you’re standing on an S Series deck and an L Series deck, you won’t feel a difference. The rigidity is identical.

Rhetorical question: Would you pay extra for a feature that doesn’t change how the boat performs? That’s the cross-member spacing debate in a nutshell.

The M-Bracket System: Where the Real Strength Lives

The cross-members are only half the story. How they attach to the pontoon tubes matters just as much. Bennington uses what they call an M-bracket—an extruded aluminum bracket that sits between the tube and the cross-member .

Here’s why this design is smart. The M-bracket has a “foot” on the bottom that spreads impact forces across the tube’s surface. Instead of concentrating all the weight of a wave hit into a small point, the foot distributes it.

Think of it like standing on a nail versus standing on a board. Same weight, different pressure.

This M-bracket system is identical across S, L, R, and Q Series. Bennington doesn’t cheapen the foundation on entry-level boats. That’s a deliberate choice .

Safety reminder: Always wear life jackets and follow local boating laws when operating any vessel. A well-constructed deck won’t save you from rough water if you’re not prepared.

Bolted vs. Screwed: The Fastener Question

One of the most common questions on Bennington forums is about how the deck attaches to the cross-members. Some manufacturers use self-tapping screws. Bennington uses stainless steel flanged elevator bolts with nylon-laced locking nuts .

Why does this matter? Screws can back out over time. Bolts don’t. And the nylon in the locking nuts creates resistance against vibration.

The 2013 forum discussion confirmed that Bennington bolts their decking rather than using screws . And here’s the key: this applies to all series. The entry-level S Series gets the same bolted construction as the flagship QX.

Have you ever heard a rattle in an older pontoon and couldn’t figure out where it was coming from? Loose screws are often the culprit. Bennington bolts prevent that.

Structural Feature Comparison by Series

This chart shows which structural features are shared across series and which are unique to L Series.

Notice how the foundation is nearly identical. The keel is the only structural difference—and even that depends on which performance package you choose, not which series.

Where L Series Actually Improves

If the bones are the same, where does your money go when you step up to L Series? Let me break it down based on owner experiences and manufacturer specs.

Fencing and Rail Construction

This is the biggest difference you’ll notice walking around the boat. L Series fencing is recessed behind the extruded rail system . That means when you pull up to a dock, the rail hits first—not the fence panels.

Why does this matter? On S Series, the fence panels are more exposed. Over years of docking, they can get scratched, dented, or loosened. The recessed design on L Series protects the panels.

Ever tied up next to a boat with scratched-up fence panels? That’s what happens when the panels are the first thing to hit the dock.

Seat Construction and Storage

The seats themselves are different. L Series uses one-piece furniture construction with five foam densities for the perfect combination of support and comfort . S Series uses similar materials but with fewer refinements.

The seat bases on L Series are also upgraded. Bennington uses two sturdy metal hinges on L Series seats . Some S Series configurations use plastic fittings that can loosen over time.

Gate Hinges

This is a small detail that makes a big difference over years of use. L Series uses piano-style gate hinges—the long continuous hinge that runs the full height of the gate . These distribute stress evenly and don’t bind.

Some entry-level configurations use smaller hinges that can wear out faster.

Rhetorical question: Have you ever fought with a sticky gate on a boat? That’s what happens when small hinges wear unevenly. Piano hinges don’t have that problem.

The Intangible: Fit and Finish

Here’s what L Series owners say when you ask them why they upgraded. It’s not one big thing. It’s fifty small things.

One owner who compared both said: “Personally, I like the small refinements of the L over the S. When we bought ours in 2017, they just had S or S premium and no L. We went S premium for those reasons. I think its worth it if the price is right” .

Another noted that the L Series replaced the old G Series boats, adding “a little more refinement and options” .

Think of it like cars. The S Series is a well-built Honda. The L Series is an Acura. Same bones, same reliability, but the Acura feels nicer everywhere you touch.

The Hull Choice: The Real Performance Differentiator

Here’s something that confuses a lot of buyers. The series (S vs L) tells you about the furniture and finishes. But the performance package tells you about the hull—and that’s what really affects rigidity and handling.

Bennington offers three main performance packages:

Two-tube (standard) – Basic. Fine for calm lakes and slow cruising. Most flex in rough water.

SPS (Sport Performance System) – Three tubes with lifting strakes. Significantly stiffer and more stable.

ESP (Elliptical Sport Package) – Three tubes with a larger, elliptical center tube. The stiffest and best-handling.

You can get SPS on an S Series boat. You can get a two-tube on an L Series (though most dealers won’t stock that combo). The series and the hull are independent choices.

One owner put it this way: “From a durability standpoint, the only area where you can ‘beef it up’ is really in the hull choice. Otherwise, all else will be equal in that regard between those line ups” .

Rhetorical question: Would you rather have an L Series with a two-tube hull or an S Series with ESP? The S Series with ESP will ride stiffer every time.

Timeline: Bennington Structural Evolution

1997 – Bennington founded. Early models use 24-inch cross-member spacing, bolted deck construction.

2000s – M-bracket system introduced. Industry-leading structural warranty established.

2010s – Competitors move to 16-inch spacing. Bennington follows for marketing reasons, despite no failure history at 24 inches .

2016-2017 – L Series introduced as premium line above S. G Series becomes L Series.

Modern Bennington boats – Both S and L share identical structural DNA. Differences are in finishes, fencing, and furniture.

The Warranty: Same Protection for Both Series

Bennington offers the same warranty regardless of which series you buy. Lifetime limited warranty on the structure, pontoons, gates, channels, motor mount, and decking. Plus a 10-year bow-to-stern warranty .

That tells you something important. Bennington isn’t worried about the S Series failing. If they were, they wouldn’t back it with the same warranty as their flagship models.

One forum member who toured the factory noted: “The guy who conducted our Bennington tour had been with them from the start and handled all the thorniest dealer warranty issues. He said in all the time they used 24” OC, they never had a claim” .

When the warranty guy tells you they never had a claim on the old spacing, you can stop worrying about whether 16 inches is enough.

What Owners Say: Real-World Experience

I’ve pulled together perspectives from Bennington owners who have spent time on both series.

The S Series owner: One buyer was deciding between an SXSB with a 150hp and an LSR with a 200hp Mercury. The family wanted the Swingback layout, which was more common on S Series in their area. The structural question came up, and the consensus was clear—no difference .

The L Series owner: Another owner who bought an L Swingback said: “We thought we bought too much boat, but have a very different opinion now. The girls love the swingback. It is awesome to make a lot of folks comfortable without actually having seats for butts” .

The structural verdict: “I’ve never seen or heard of a pontoon deck failing because it didn’t have through bolts, or because its cross-member spacing was XX compared to competing brands. If these OEMs were making inferior products they would not be in business” .

Rhetorical question: Have you ever met someone who regretted buying an S Series because the deck flexed? I haven’t either.

Comparison Table: S Series vs. L Series Structural Features

Feature	S Series	L Series	Difference?
Cross-member spacing	16″ OC	16″ OC	None
Deck attachment	Bolted	Bolted	None
M-bracket system	Yes	Yes	None
Baffled pontoon chambers	3+ per tube	3+ per tube	None
Solid extruded keel	Optional (with SPS/ESP)	Optional (with SPS/ESP)	None
Fencing attachment	Bolted through deck	Bolted through deck and channels	L Series has recessed panels
Gate hinges	Standard	Piano-style	L Series upgrade
Seat hinges	Mixed	Metal hinges	L Series upgrade
Seat construction	Modular on some models	One-piece	L Series upgrade

Making Your Choice: S or L?

Here’s my take after reading everything I could find on this topic. The structural difference between S and L Series is negligible. Bennington builds the same foundation for both. The cross-members, the bolts, the M-brackets—identical.

So how do you decide?

Buy S Series if:

• You want the best value in the Bennington lineup
• You’re planning to keep the boat for 5-10 years (it will easily last that long)
• You care more about layout and engine than about stainless trim rings
• You want to put your budget toward performance (ESP hull, bigger motor)

Buy L Series if:

• You plan to keep the boat for 15+ years (the refinements hold up better)
• You dock in tight spaces where recessed fencing matters
• You notice and appreciate small details in fit and finish
• The price difference (typically $5,000-10,000) doesn’t stretch your budget

One owner summed it up well: “Find the boat that fits your needs, in your budget, and is appealing to your eye and you will be happy” .

What’s your favorite Bennington boat feature or on-the-water experience? Share your thoughts in the comments below.

References:

• Pontoon Forums – Construction of New Pontoon Boats Discussion
• Club Bennington – S Series vs L Series Deck Construction
• Bennington Marine – 2021 Lineup Overview
• Westshore Marine – Why Bennington Pontoons Outsell the Competition