responding to a few of the comments and adding some of my own.
Can you buy a decent cat for 100K. Yes. Would it have to be a
gemini? No. I dislike them for a variety of reasons but there are other, older boats out there that are perfectly capable and built for blue water if that's your plan. Do guests go sit on the tramp? Well duh! I have a solid bridgedeck and my guests are constantly moving around all the time. There's always someone to talk to when I'm on the helm, some are here, some are there.
It will cost twice as much because it's a
multihull. Wrong.
Rigging is the same and 1/2 the cost if you bought a
Ketch. Bottom job is comparable to a similar mono because very little of the bottom is below the water. My cat is 35' long. Fits in a standard slip and can be hauled out with a standard travel
lift. Yes, the yards will try to gouge you because it's a multi. I explain that while it's a multi it's no different than a similar sized
power boat and no, I'm not paying a premium for nothing. Takes some discussion but I've worked it out with boat yards before. Depending on your
power you might have 1 or 2 engines either inboard or
outboard. Most of the time I'm running on one engine. 2nd engine gives me a whopping 1.5 knots extra speed at twice the
fuel burn. I run 1 engine 1 day, the other the next trying to keep the hours similar. Maintenance is a bit more but really not all that much.
Oil changes are spread out twice as long because I'm splitting the time between engines. I've had a large mono to compare costs by.
Cats are
lightning fast. False. Some cats are for sure. Cats are either performance cats, cruising cats or condomormancats. Performance cats are a blast but your'e not going to find one in your price range. Cruising cats will sail faster off the wind in general than their mono counterparts, condomoran cats are built for the
charter fleet. Built for 1-2 weeks at a time on
vacation with lots of people in private cabins. Tons of party space. Not built for speed.
Cats don't point upwind. This was very true in the early years of cats but modern cats point acceptably high.
Turning. Cats above about 37 feet because of their wide spread hulls will not tack across the wind without assistance. It's a law of physics. You get used to turning on the
outboard hull engine to tack through and then shutting it down. On the ocean or a big bay, no big deal. On the
Columbia river.... a pita for sure.
I've owned both, Captained both in both
charter and private yachts. Either are fun. For me, I love sailing flat, safer to move about the deck and having less things fall off the shelf. That said, on a beam reach with 2' wind waves generated from shore (30-35 knots) created an ugly fetch that was just the perfect timing and set to set up a harmonic effect that launched anything and everything onto the
cabin sole. A mono would have just breezed through it. That's only happened once in all the years I've sailed cats. There is no "perfect" boat.
Lastly. 100k budget. No matter what boat you buy, it is going to need
work done, upgrades etc. Make sure you have a reserve budget for that even if you know how to do all the
work yourself. It takes time and
money.
Charter more boats, both mono and multi and then decide which feels best to you. If your'e plan is to go cruising, 90% of your time will be at anchor or a
dock. I prefer a veru comfortable living area and the cat gives me that.