When two boats share the same hull type — in this case both the Tiara Yachts 3600 Open 2012 and the Tiara Yachts 3900 Convertible 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?

On paper these two are close siblings in the size department — Tiara Yachts 3600 Open 2012 at 38,9 ft versus Tiara Yachts 3900 Convertible 2010 at 41,6 ft. Weight tells a clearer story for trailering families: the Tiara Yachts 3900 Convertible 2010 tips the scales at 30 125 lbs — 29 934 lbs less than the Tiara Yachts 3600 Open 2012 at 191 lbs. That difference is meaningful if you're working within a half-ton or three-quarter-ton truck's tow rating, especially once you factor in a motor, gear, and fuel.

The Tiara Yachts 3600 Open 2012 carries a rated maximum of 380 hp. Engine data for the Tiara Yachts 3900 Convertible 2010 wasn't available in our records — check the manufacturer's spec sheet before sizing a motor.Fuel capacity breaks the other way: the Tiara Yachts 3900 Convertible 2010 carries 475 gallons versus 35 gallons in the Tiara Yachts 3600 Open 2012. 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 Tiara Yachts 3900 Convertible 2010 is rated for 12 passengers, while the Tiara Yachts 3600 Open 2012 caps at 11. If you're regularly pulling extended family or a group of friends onto the water, the extra seats on the Tiara Yachts 3900 Convertible 2010 could be the deciding factor.