When two boats share the same hull type — in this case both the Navigator Yachts Navigator 5100 2010 and the Navigator Yachts Navigator 5800 2010 are deep vee designs with fiberglass construction — the buying decision usually comes down to a handful of practical questions: how many people are you putting on the water, how far do you trailer, and what does your tow vehicle weigh?

Size is the most obvious dividing line here. The Navigator Yachts Navigator 5800 2010 measures 57,8 feet overall (2010), giving it roughly 6,2 additional feet of deck space compared to the Navigator Yachts Navigator 5100 2010 at 51,7 feet (2010). At 5 lbs and 56 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.

Both boats share a closely matched power ceiling — 500 hp for the Navigator Yachts Navigator 5100 2010 and 500 hp for the Navigator Yachts Navigator 5800 2010. Real-world performance will come down more to which motor is actually bolted on, its load at the time, and whether it's a 4-stroke or 2-stroke setup. Fuel capacity breaks the other way: the Navigator Yachts Navigator 5800 2010 carries 75 gallons versus 6 gallons in the Navigator Yachts Navigator 5100 2010. On a lake day that's negligible, but for coastal cruising or long reservoir runs the extra range matters.

For family outings this is probably the sharpest distinction between the two. The Navigator Yachts Navigator 5800 2010 is rated for 17 passengers, while the Navigator Yachts Navigator 5100 2010 caps at 15. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Navigator Yachts Navigator 5800 2010 could be the deciding factor.