@Rain City, you need to keep this in mind for your boat choice. General rules of thumb:
Gas engines: 4.3L engine, 8 gallons per hour at cruise. 5.0L 10 gallons per hour at cruise. 5.7L 12 gallons per hour at cruise. 7.4L/8.1L 15 gallons per hour at cruise. Per engine.
Diesel engines: horsepower x .0375 for gallons per hour at cruise. Example: 370hp cummins = 370 *.0375 = 13.8 gallons per hour per engine t cruise.
If you get into a Tiara, most of them are straight shaft inboard boats. When you have straight shaft or V-drive transmission you should take 20% off cruise efficiency vs. legs or outboards. Simpy has to do with drag in the water, as well as the direction of the thrust of the shaft/v-drive not being adjustable with any method of trim.
So if you get into a Tiara with twin 5.7L engines, you can expect to burn about 24 gallons per hour at 25mph. That's 91L x $1.60 per litre = $145.00 per hour at cruise. If you plan to go to Thrasher and back to Vancouver you're looking at $300-400+ just for gasoline on the day.
You have to ask yourself if that kind of fuel burn will make you use your boat less.
I used to run a 42 Tiara w/ twin QSM11 Cummins and burned 40 gallons per hour at 30mph. I was burning $250 per hour, or $600-700 per Thrasher day trip. I stopped using the boat for fishing and only cruised it where the fuel burn could be offset by being away for a few days.
I now run a 42 Lindell that burns 20 gallons at 30mph. $125 per hour. Volvo IPS technology.
At the end of the day you need to ask yourself - are you going to be happy putting $300-400 per day into your boat to go to Thrasher from Vancouver?
Your current boat has a 5.0L so you're burning 10gph at 3600rpm and 12-13gph at 4000rpm.
Food for thought in your decision making process... I see in your last message you are trying to see if you can justify permanent moorage. I suggest to you your fuel burn will be significantly more.
Traditional boat usage is 100 hours per season here. Assume twin 5.7L at 24 gph x 100 hours = 2400 gallons. = 9500 litres approx. = $15,000 in fuel, approx.