Larson SEi 180 Fish Series I/O 2005 boat specs
Larson
Larson SEi 180 Fish Series I/O 2005
2005
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VS
Larson Senza 186 2009 boat specs
Larson
Larson Senza 186 2009
2009
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Larson SEi 180 Fish Series I/O 2005 vs Larson Senza 186 2009 — Same Brand, Different Boat

The Larson SEi 180 Fish Series I/O 2005 vs Larson Senza 186 2009 comparison sits squarely in the category of decisions where specs alone won't tell the whole story — intended use, storage, and long-term ownership costs all factor in.

For family outings this is probably the sharpest distinction between the two. The Larson Senza 186 2009 is rated for 9 passengers, while the Larson SEi 180 Fish Series I/O 2005 caps at 6. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Larson Senza 186 2009 could be the deciding factor.

Bottom line: Choose the Larson Senza 186 2009 if your priority is putting more people on the water — it handles 9 passengers and at 18,0 ft it has the deck room to back that rating up comfortably. The Larson SEi 180 Fish Series I/O 2005 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 6 that costs less to run day-to-day.
General Boat Info
MakeLarson
MakeLarson
ModelSEi 180 Fish Series I/O
ModelSenza 186
Model Year2005
Model Year2009
Measurements / Dimensions
Beam7 ft. 9 in
Beam7 ft. 10 in. (2.39 m)
Beam - Meters2.36
Beam - Meters2.39
Beam - Inches93
Beam - Inches94
Deadrise21℃
Deadrise21℃
Draft [max] - Detail31 in. max
Draft [max] - Detail33 in. (83.8 cm)
Draft [max] - Meters0.79
Draft [max] - Meters0.84
Draft [max] - Inches31
Draft [max] - Inches33
Weight - Detail2,650 lbs. apx
Weight - Detail2,700 lbs. (1,225 kg)
Weight - kg1202.02
Weight - kg1224.7
Weight - lbs.265
Weight - lbs.27
Length overall - Detail17 ft. 6 in
Length overall - Detail18 ft. 6 in. (5.64 m)
Length overall - Meters5.33
Length overall - Meters5.64
Length overall - Inches21
Length overall - Inches222
Length - Metersnot available
Length - Meters5.64
Length - Feetnot available
Length - Feet18
Length - Inchesnot available
Length - Inches6
Body / Hull
Hull materialFiberglass
Hull materialFiberglass
Hull typenot available
Hull typeModified Vee
Engine and Drivetrain
Fuel tank capacity - Detail23 gal
Fuel tank capacity - Detail29 gal. (109.8 l)
Fuel tank capacity - Liters87.06
Fuel tank capacity - Liters109.78
Fuel tank capacity - Gal23
Fuel tank capacity - Gal29
Fuel typenot available
Fuel typeGas
Drive typenot available
Drive typeI/O
Operational Info
Maximum capacity1,100 lbs
Maximum capacity1,400 lbs. (635 kg)
Maximum people6 Persons
Maximum people9

Larson SEi 180 Fish Series I/O 2005 vs Larson Senza 186 2009 — Common Questions

Which is easier to trailer — the Larson SEi 180 Fish Series I/O 2005 or the Larson Senza 186 2009?
For trailering, the Larson Senza 186 2009 has the edge at 27 lbs dry weight versus 265 lbs for the Larson SEi 180 Fish Series I/O 2005. Add a motor (typically 300–500 lbs for an outboard in this class), gear, and a partial fuel load and the difference grows. Lighter is friendlier on smaller tow vehicles and on fuel economy while hauling.
How many people can each boat hold?
The Larson SEi 180 Fish Series I/O 2005 is Coast Guard rated for 6 passengers, while the Larson Senza 186 2009 is certified for 9. Note that legal capacity and comfortable capacity aren't always the same thing — on a full day out, most experienced boaters aim for about 80% of the rated number to keep things comfortable.
Which boat is wider, and does it affect trailering?
The Larson Senza 186 2009 measures 94" wide, compared to 93" for the Larson SEi 180 Fish Series I/O 2005. The US standard-width towing limit is 8’6" (102") in most states — anything over that may need a wide-load permit. Confirm your specific route requirements with each state's DOT.
Which boat has the larger fuel tank — the Larson SEi 180 Fish Series I/O 2005 or the Larson Senza 186 2009?
The Larson Senza 186 2009 has the bigger tank at 29 gallons, versus 23 gallons on the Larson SEi 180 Fish Series I/O 2005. That 6-gallon difference translates to roughly 18–30 nautical miles of additional range at cruising speed, depending on motor, load, and conditions.
Are the Larson SEi 180 Fish Series I/O 2005 and Larson Senza 186 2009 from the same manufacturer?
Yes — both the Larson SEi 180 Fish Series I/O 2005 and the Larson Senza 186 2009 are built by Larson. That means shared dealer networks, common parts availability, and consistent build quality across the line. The choice between them is essentially a question of how much boat you need, not which brand you trust.