Galeon built the same forty-five-footer twice.
The 435 GTO is 44' 9" with three outboards on the transom, running to 51 knots. The 435 GTI is 44' 11" with twin inboard diesels at 480 hp a side, running to 32. They share a 13' 6" beam, two cabins, one head, and a fourteen-person capacity. Two inches of paperwork apart on length, and not remotely the same boat to own.
Most buyers walk into this decision already certain which side they are on. A good number of them are wrong, and the reason is that the differences that decide it are not the headline ones.
Start at the transom
Take three outboards off the back of a 45-foot boat and the aft deck becomes deck.
That is the first and most physical consequence of the GTI's layout. There are no engines to sit behind, no engine wells to step around, and water access is direct. On the outboard boat the back of the boat is a machinery space with a swim platform attached; on this one it is living space. On a hull this size that is more square footage than the description suggests, and it is the difference you notice standing on the boat rather than reading about it.
The silhouette stays low and sporting in the GTO manner. What changes is what the back half is for.
The galley is below deck
This is the line that will actually decide it for most owners, and it does not read like much on a spec sheet.
On the GTI the galley is on the lower level rather than in the cockpit. Which means you can cook in it when the weather turns: wash up, put things away, and get under way without clearing a cockpit counter first.
If your weekends are a cooler and a grill, that is worth nothing to you. If your weekends involve real meals - and particularly if some of them happen in the rain - it is worth a great deal, and it is the clearest way to tell which of these two boats you are. Spend a wet Saturday afternoon trying to make lunch in an open cockpit once and the argument settles itself.
The hull, and the speed you give up
The GTI runs a deep-V hull under twin inboard diesels sitting low and amidships, rather than 1,800 hp cantilevered off a transom. Centre of gravity is lower and further forward. The boat carries its weight the way a sport cruiser is supposed to, and a deep-V under inboards is a quieter and more settled ride in a head sea than the top-speed comparison would lead you to expect.
Nineteen knots is still nineteen knots. Thirty-two against fifty-one is what the layout asks of you, and there is no arguing it away.
The number to bring back from the sea trial is the burn: ask for observed speed and fuel burn at your intended cruise rpm, in writing, and do the range arithmetic yourself off 370 US gallons.
Draft: one number instead of two
The GTI draws 3' 10", and it does not move.
The outboard boat draws 3' 1" trimmed up and 4' 5" trimmed down, and it is the second of those figures that applies when you are idling a channel at low water rather than running trimmed out. So the useful comparison is not 3' 10" against 3' 1" - it is 3' 10" against 4' 5", and on that reading the inboard boat is the shallower one where it counts.
What you lose is the option. There is no trimming up to sneak over a bar. A fixed number is easier to plan a season around, but it is a floor rather than a range, so check it against your own home channel at low water.
Tankage tells the whole story
370 gallons of fuel and 106 gallons of fresh water on the GTI. 528 and 79 on the GTO.
Less range at speed, more time comfortably at anchor. Twenty-seven extra gallons of water is the difference between a weekend and a long weekend for four people, and it is not an accident - it is what the boat was provisioned for.
Below deck
The forward cabin takes a comfortable double bed with a screen and real storage worked in around it. The aft cabin can be specified with sliding berths that push together into a double when you need one and stay apart when you do not, which is what keeps a two-cabin boat useful for guests, for children, and for couples who want different things on different weekends. One head serves both.
The main salon runs panoramic windows on both sides. With the galley and the accommodation below and the salon glazed, the lower deck is a genuine second living space rather than somewhere you go only to sleep - which is what an inboard layout buys and an outboard layout mostly does not.
On the main deck the cockpit carries a well-equipped wet bar, with a convertible sunbed aft on the options list.
Where it sits in the wider market
The GTI lands in the 43-to-47-foot inboard sport cruiser class, which is crowded and well established in Europe. Those boats will match it on accommodation and often beat it on cabin count.
What the GTI brings that most of them do not is the profile. This is a genuinely sporting shape rather than a flybridge boat with the top taken off, in a size where most of the sporting energy in the market has migrated to outboards. If you have been shopping outboard boats at 45 feet and keep coming back to the noise, the transom clutter or the cockpit galley, this is the boat to sea-trial before you decide the category is settled.
What to do before you sign
Get the fuel burn at your cruise rpm in writing. Check 3' 10" against your home channel at low water, not at average. And if you can arrange it, run the two 435s back to back on the same afternoon. An hour in each settles this decision permanently, and no spec sheet is going to do it for you.