Where could you actually go for the weekend?
Start with the trip, not a made-up fuel figure. Tell CYR where the boat is based and where you want to go. If you do not know the destination yet, choose the sort of weekend you want and use it to judge realistic nearby cruising options.
Your weekend route
Your marina → destination to choose. CYR should suggest suitable easy destinations once the starting marina and the boat's real range are known. Weather, tides, sea state, marina access and skipper experience must still be checked before departure.
Take the boat
Fuel: use the boat's real engine consumption, cruising speed and route distance when known. CYR does not invent litres-per-hour from an advert.
Drive + hotel / B&B
Same people, same nights. Road fuel is about 34 litres / £49 with the current inputs. This compares the weekend trip only; annual ownership, servicing, insurance and mooring remain separate costs.