A top speed is the flattering number. It is easy to reach on a light boat on a flat day, and it has very little to do with how you will actually use the boat. The number you want is the one you will hold for four hours with the family aboard.
On the Manhattan 55, Sunseeker gives you both. Twenty-five knots cruise, against a maximum of up to 32 knots. That is a good place to start on this boat.
The numbers
Length overall is 56' 6". Beam is 16' 0". Draft is 4' 6", quoted as maximum at full load. Displacement is 59,524 lbs at half load. Fuel is 580 US gallons, fresh water 158 US gallons, and there is a 39 US gallon black water tank. Accommodation is three cabins and two heads.
Read that displacement figure carefully, because it is a place buyers get caught. Half load already carries a working amount of fuel, water and gear. If you are comparing against a builder who quotes light craft condition, you are not comparing like with like, and the Sunseeker number will look heavier than it is.
The same applies to the draft. Four foot six is a maximum at full load, not a bare-hull figure. For a 56-foot flybridge that is genuinely shallow, and it is one of the practical arguments for this boat over some of the Italian competition at the same length.
Shafts or pods, and why you should decide first
Sunseeker lists two engine packages against this hull. Twin MAN i6-800s, at 800 PS each. Or Volvo Penta IPS-950s. Propulsion on the specification reads shafts or pods depending on which you take. Both drive the same 56' 6" hull to the same 32-knot maximum and 25-knot cruise.
This is not a trim level. It is two different boats to own.
Pods will make you look competent docking in a crosswind, and the joystick is the single feature most likely to make a nervous spouse comfortable with the boat. They are also more complex under the water, and the service relationship is different.
Shafts are conventional, well understood by any yard, and considerably more forgiving of the day you find the bottom. On 4' 6" of draft in the Bahamas or the shallower stretches of the ICW, you will find the bottom eventually. Everyone does.
Neither is the right answer in general. But it is a decision you make once, and it is not something you change later, so make it before you start looking at specific hulls rather than after you have fallen for one.
While you are at it, note the generator: 11 kW at 50 Hz or 13.5 kW at 60 Hz. A US boat takes the larger set.
The aft deck is the sales pitch, and most of it is optional
The bathing platform running into the Beach Club is the reason a lot of people buy this boat. It is where the day actually happens. Sunseeker's own page lists a built-in barbecue, an overhead shower and fold-down transom seating for that space.
It lists them as options.
That distinction is invisible in a photograph and invisible in a brochure gallery, and it is the single most common way a buyer ends up disappointed at handover on a boat this size. Get the build specification of the actual hull, not the model page, and check each of those three items individually.
The same discipline applies inside. The bar stools at the main-deck galley counter, which are a large part of why the galley-and-cockpit arrangement works socially, are also listed as an option.
The Manhattan 56 question
There is a second boat in Sunseeker's current range with an identical specification. The Manhattan 56 publishes the same 56' 6" length overall, the same 16' 0" beam, the same 4' 6" draft, the same 59,524 lbs half-load displacement, the same 580 and 158 gallon tanks, the same three cabins and two heads, the same 32-knot maximum and the same 25-knot cruise.
Not similar. Identical, to the digit, on every published figure. Sunseeker's own copy for the 56 describes it as running on a proven hull platform, which is the yard saying the same thing in marketing language.
What separates them is the generation of everything above the waterline. The 56 carries a 2026 exterior profile with expanded main-deck glazing, the first showing of Sunseeker's new exterior upholstery collection, an aft cockpit rebuilt around modular seating that converts between dining, lounging and a full-beam sunpad, and the latest Sunseeker Interiors Collection below with a full-beam master. The 55 is the earlier presentation of the same platform. Sunseeker took the 56 to its Cannes Yachting Festival stand for September 2026 and did not take the 55.
So the honest framing is this. If you want the current deck and interior programme, buy the 56. If you want this platform and would rather put the difference into specification, the 55 gives you the same naval architecture and the same performance envelope. Anybody who tells you one of these boats is faster, roomier or more seaworthy than the other is telling you something the published data does not support.
What to check on sea trial
On the trial, bring the boat to your intended cruise speed, hold it there long enough for the numbers to settle, and have observed consumption recorded in writing along with the sea state, the load aboard and the trim. Do that and you know what 580 gallons is actually worth to you, on this hull, in the condition you will run it.
Do the same at wide-open throttle so you know whether the boat makes its 32 knots in the condition it is actually in. That report is worth more to you than any brochure figure.
Then check the water. One hundred and fifty-eight US gallons with a transom shower in use and six people aboard is the tank that will end your weekend before the fuel does.
Where it fits
Cross-shop it against the Princess F55, which is the closest thing to it on paper at 57' 9" with the same three-cabin, two-head arrangement, and the Galeon 520 FLY at 56' 5" if you want to see how much feature content another builder puts into the same slip length. If you need a fourth cabin or crew quarters, none of these will do it, and you are looking at the Manhattan 68 instead.
The rest of the family is on the Manhattan series page.