To the OP:
You’ve run up against one of the fundamental design problems of cruising sailboats, a problem which severely impacts
boats even much bigger than the one you are contemplating. See for example the thread on the “Ideal 60 – 65’ Cruising Boat” which has been active recently.
Your design specification is not realizable on a boat the size of a
Pearson 365, or even one much bigger. You will have to make a painful compromises here or there or in several places.
I have a lot of miles in a
Pearson 365, as it so happens, and the dinghy solution was this: Garhauer
davits and separate stowage of the 5hp
engine on the rail. AB 9’ soft floor dinghy. Roll up the dinghy on
passage. The painful compromises here? Let me count the ways:
1. A 9’ soft floor dinghy won’t carry four people and a dog, and won’t plane. It’s just a little tub to
ferry two, maximum 3 people to a very nearby landing.
2. The
davits look awful, add length, add windage which noticeably hurts sailing performance, and create a structure good for bashing into piles as you push off a berth. On the plus side, at least you get a place to put your
solar panels (whoopee).
3. Getting the dinghy up and down is a pretty laborious process – you have to take the
motor off and crane it up (or down) separately, put it together, etc.
4. Deflating and rolling it up for passages is a real PITA. And then you have to stow the rolled up dinghy
This is probably the best possible dinghy solution for a boat this size, but one has to admit that it is basically a crap solution.
As
boats get bigger, this problem does allow solutions with progressively fewer painful compromises. But they don’t disappear until a boat is well into superyacht territory.
My present boat is 54’ on
deck, 16’ beam, and two and a half times the
displacement of a P365. That ought to give me some wiggle room, no? But my dinghy solution is still unsatisfactory. I have a 3.4 meter (11’)
Avon rib with center console and
wheel steering, and a 25 horsepower
outboard. So far so good – this is now finally a dinghy which fulfills something like your design specification – you can carry four or even five people in it, and it will plane even with 5 on board, if the people aren’t too porky. With
wheel steering, it’s comfortable to drive for longer distances, and so you can really get out and go places and explore on this dinghy. It’s not big enough to be actually
seaworthy, but I have crossed the Solent four times in it (which goes fast at 30 knots), and you can even pull a waterskier. Since my boat lives on a mid-river
mooring with no walk-on access, the dinghy is extremely important – it really is my
family car, almost literally. I have to get in the dink every time I walk on shore for anything, and I use the dink to buy groceries and all kinds of other things.
OK, but that’s about all the good. Here is the bad:
1. Such a dinghy weights 150kg or probably more, and requires massive powered davits to
lift conveniently.
2. These massive powered davits are hideously ugly and completely ruin the beautiful lines of the boat.
3. These massive powered davits add 6 feet to my boat’s
LOA, complicating berthing and making
Med mooring impossible.
4. The davits plus dinghy create massive windage.
5. 150kg of dinghy plus the davits and
hardware add a considerable amount of weight far out at the end of the boat, with corresponding effect on trim and polar moment of inertia – negative effects of course.
6. The davits are horrendously unreliable and require constant
repair. . By far the all-time star of my to-fix list. Now the lifting mechanisms have been out of commission since the spring with
parts impossible to source, and I have to use a block and tackle instead. Oh, joy.
7. You cannot store a dinghy of that size on
deck of even a big boat like mine. So you are
Did you guess by now that I hate my davits?
So on a boat the size of a P365, you will need to start out with the proposition that you are essentially screwed however you figure it. In my opinion, there are two kind of major ways to go:
1. Do like my example above and fit the davits and live with the disadvantages of them. Try to choose the best possible dinghy which will fit them. Maybe an air floor dinghy will
work better than the soft floor kind I used to use. Maybe you could squeak in a little bigger one – maybe 10’? But remember that the bigger it is, the bigger the other headaches – it’s a no-win situation.
2. Or skip the davits, and save the windage,
LOA, and other issues. In this case, you will have to commit to inflating/deflating, rolling up/unrolling the dink very often, craning it on and off the deck, and so in this case you really won’t want anything bigger than 9’. You will compromise severely on convenience and functionality of the dinghy, but at least you won’t screw up your boat.
There are other solutions -- PortABotes, which fold up and can be lashed to stanchions. Just to name one example. Hard dinghys. Towing. But inflatables are the choice of 97% of cruisers for very good reasons -- they are much more stable, don't scratch your topsides, and some of them can be rolled up.
There is no "recipe for happiness", in my opinion. Just various more or less painful compromises. I can't even solve it on my 54' boat. One of the best solutions I've seen is on the 64' Halberg-Rassey -- which has a kind of "hangar deck" behind the transom, which swallows a small RIB whole and serves as a kind of uber-lazarette. Other than occupying an awful lot of
hull volume, that doesn't really have any disdvantages. But that doesn't really
work on a boat less than about that size. So the rest of us can dream on. . . .