BoatFortress

Yes that makes sense, it's not really practicable, at either front, middle or back. For reference I mean something like terrible mspaint cross-section on part of the boats length - with the dashed green being an awning, orange being a part removable section and red being temporary raised flooring - but even stuff like a tilt would make it tricky. Going to go back looking for budget widebeams I guess, although I could start with a narrowboat and sell it for a widebeam in a few years bearing in mind depreciation. 🤔

fair point, you’d need to rebalance it constantly, and the floor would be constantly tilting slightly.

indeed I guess I could make a secondary “floor” at the height of the hull but that would mean extending the roof/awning by that much in that area of the boats which would need a lot more cutting into the shell, with attendant waterproofing and insulation issues, and would need to take down that bit for low bridges or seperation. Unless I just have a covered large area at the front or stern rather than in the cabin middle.

Yes I meant either ropes, or some kind of reconfigurable joint bracing system to keep doorways in line. Yes, I guess the costs of two BSSs, licences, and insurance policies would add up, even if you take out the initial cost of the boat(s) and don’t compare like for like.

True, initial cost could be a factor if widebeams are significantly more than double the cost of narrow, you want to travel on more canals, or want to be able to effectively up or downgrade floorspace.

Are sliding doors or wing doors practicable or too hard to seal effectively if closed? so as long as connections are made only through the cabin side (assuming this means the superstructure above the hull), there will be no problems. Below, and you might have trouble with wind and waves. yes! Not sure if you can increase cabin level floor space when not moving though. EDIT: not sure if you could resolve ballast by pumping water between the tanks.

Great, thanks both! What restrictions are there on widening the sidedoors on the shell for a better connection? For example I’m assuming you can’t increase depth of the door and without risking sinking like the HMS Captain or the swedish Vasa.

Great, could you please tell me the search terms? "catamaran" and "widebeam" didn't help that much. Assuming seperate licenses, is there anything else required by the CRT?

can you take two 6ft width narrowboats and convert them into a 12ft width convertible catamaran? Just thinking some kind of removable series of structural joins length wise down the hull, and a control mechanism for keeping both engines at halfspeed - maybe a removable prow?