Originally Posted by AD28
geez, NOBODY has EVER done this before...
I know! I'm a genius! ^O_O^
I've never heard of either of those search terms before associated with cats and didn't know that 'demountable' or 'folding' were the terms i'm looking for. However that's not quite what I had in mind...
I'm wondering something larger in scale and ocean going, able to handle larger seastates including accidental ones you can't get out of the way of and wondering how far the idea can be pushed. 6 foot seas in a 30 footer i'm told is pretty rough going, 6 foot seas in an 80 foot catamaran
with wave piercing hulls is not much of a big deal. When i'm told that's pretty common sea state for oceangoing passages i'd like to see what I can do about that.
My goal is to stretch the hulls out "as long as I feasibly can" to get some of the wave averaging effect that only length can get you (50ft? 70ft? 90ft?) but primarily having that in the hulls. Think a man on skiis. :^) I'm not building an "80 foot boat with the room of an 80 footer" but more like a 30-40 foot liveaboard
boat with the cat hulls of closer to an 80 footer. By spreading the weight bearing into length instead of wider cat hulls i'm hoping drag might also be less improving efficiency too. (the narrowness i'm hoping overcoming the increase in wetted area, though I haven't run calculations on it yet there may be points of diminishing returns)
Because of shear forces on superlong cat hulls under rough conditions if you make a mistake or get caught off guard, i'm wondering if I could even convert between "longest hulled passagemaking mode" and "shorter hulled survival mode" (potentially along with the third "minimum footprint possible" for just floating in the marina at the 40 foot dock price
instead of the 80 foot dock
I mean I want the long hulls and wide stance to stabilize the waves but at some point if they're too long (if the idea is taken too far) the weight added for strength starts to defeat the purpose of efficiency. It might have to be that things compact in a bit or hull
extenders remove so they don't get broken off if bad planning (or if it were a sail only vessel unable to move fast enough) means being stuck in rougher conditions than planned. Wouldn't have to reduce the floatation, they might just be put in a position (like folded back alongside the center part of the main hull, so it almost looks like four hulls if the extension is all on the front) to reduce the risk of shear loads tearing the cats off.
The discussion about trailering is more just wondering out loud how far the idea might be taken... the end result might require a class 8 truck but still technically be overland moveable, which might be fine as after some oilfield driving I might end up owning one. (i'm wondering if moving by truck overland in Panama
would be cheaper than going through the Panama locks or something though, even if in "hulls compressed" mode to take less space up) Or I might be curious how far the idea could stretch and still be Class 8 moveable. But trailerability is not the only reason - I think this is a design i'd like considered whether it was a 40 foot great lakes
cruiser, 80 foot ocean going, or 160 foot megayacht.
If youre thinking i'm nuts, the biggest issue is more how far the idea is taken rather than existing at all. I'm sure a Catamaran that widens from 8 feet road hauling to 12 feet stability is no big deal, but wonder whether that idea can still work at 16 feet or 20 feet wide before too much weight is added to have proper strength. (I suppose at some point modular boats that can break down/be hauled in two chunks become possible - but again diminishing returns) I'm sure a Catamran with small hull extenders that goes from a 32 foot long roadgoing mode to 42 feet for a little more stability isn't going to push the limits of engineering, but one at 64 feet potentially would. This is sort of a feeler to see if anyone has done THAT before/not just implementing the idea but pushing it to what I see as an evolved form. Length+width = stability and comfort, and thus a good i'd like to pursue, without ending up with some critically dangerous flaw obviously.