The Achilles LT-4 2006 vs Achilles SU-18 2006 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.
Size is the most obvious dividing line here. The Achilles SU-18 2006 measures 18,0 feet overall (2006), giving it roughly 10,0 additional feet of deck space compared to the Achilles LT-4 2006 at 8,0 feet (2006). At 56 lbs and 44 lbs respectively, both sit in a similar weight class — either should pair comfortably with most mid-size SUVs and half-ton trucks, though always confirm your specific tow rating with the motor added.
The power gap is worth calling out. Rated to 90 hp, the Achilles SU-18 2006 has a 87-hp advantage over the Achilles LT-4 2006's 3-hp ceiling — enough to notice on acceleration and at cruising speed, particularly with a full passenger load.
For family outings this is probably the sharpest distinction between the two. The Achilles SU-18 2006 is rated for 11 passengers, while the Achilles LT-4 2006 caps at 4. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Achilles SU-18 2006 could be the deciding factor.
At this size, power-to-weight ratio matters more than outright horsepower. The Achilles SU-18 2006 comes in at 1 lbs per hp versus 19 lbs per hp for the Achilles LT-4 2006. The lower the ratio the more explosive the acceleration — meaningful on a short RIB where bursts of speed, quick planing, and agility in surf or tight waterways define the experience.
Bottom line: Choose the Achilles SU-18 2006 if your priority is putting more people on the water — it handles 11 passengers and at 18,0 ft it has the deck room to back that rating up comfortably. The Achilles LT-4 2006 is the smarter pick if you want a lighter, easier-to-trailer boat rated for 4 that costs less to run day-to-day.