T&T: Catamaran vs monohull

[Candy Chapman and Gary Bell]

Mervyn Carr again asked:  

Compared to the cat (imo)the mainship is a distant second in terms of
comfort and stability. Now maybe the question should be, "is the Mainship
(34' 1979) just not particularly stable/seaworthy?" or "is the cat way nmore
stable?"


Yes, the Mainship (and any similarly sized monohull as well) is 
considerably less roll stable than any wide stance catamaran.  Pretty 
simple geometry there.
As I suggested in my earlier rant, your Mainship is MORE stable in pitch 
than any slender hulled boat, particularly a catamaran like mine.  As I 
also pointed out, roll stability is a more often encountered gremlin 
than pitch, and a pitch stability challenge can be converted to take 
advantage of a catamaran's roll  stability  with  course and/or speed 
changes, stern anchors, anchor bridles, etc.. 

I sense that your two questions are really only one.  Yes your Mainship, 
and any similar monohull is overall less stable than a catamaran (or 
trimaran, or proa too of course) because of the shape of the 'footprint' 
on the water, but that is of course a subjective evaluation from someone 
with a dog in this fight.  A monohull can be turned into the waves to 
regain the advantage of it's inherent pitch stability, while a catamaran 
can be turned to convert a challenge from pitch to roll.  However, the 
catamaran motion will only have the higher speed motion of a rolling 
monohull when it is in the harmonic hobby horse pitching mode, and that 
in my experience is very seldom found and quite easy to mediate or even 
eliminate.  Your own experience seems to coincide with mine, that the 
pitching motion of a monohull, even when properly aligned and pitching 
in the waves is less comfortable than the motion of a catamaran, 
oriented to take the waves broad on the bow.  Others may not agree, but 
I might challenge them to come cruising and anchoring with us, and spend 
some significant time aboard both sorts of boats.  I expect that in the 
boat motion catagory at least, the cat has the advantage.  Hence my 
comments about how suitable it is for general boating.  Fuel economy vs. 
speeds available and the internal space and amenities are of course 
important issues for us as trawler trash.   

Marin's comments on his preference for traditional boat appearance 
agrees very well with the general consensus of the marketplace.   There 
are a lot more traditional looking trawlers out there than power 
catamarans, and it's nice that somebody loves them!  Power catamaran 
sales, while growing faster than the manufacturers' ability to produce 
them, for the PDQ and a few other makes at least, still lags far behind 
monohull sales, due in large part to the fact that we all make major 
acquisition choices, be they boats, cars, houses or spouses based in 
large part on how they look (I consciously elected to NOT use the term 
'curb appeal' there!), and particularly how they resemble our 
preconceived notion of how the ideal boat, car, etc. would look.  When 
The Admiral and I bought our boat, PDQ sales manager Rob P. suggested 
that over ninety percent of the early PDQ sales were to folks who had 
NOT had a large power boat in the past -- and therefore had fewer 
preconceived notions of how they should look.  Might you be suffering 
from a disconnect between how you think a boat should look and how those 
boats compare to catamarans in several performance issues?  I came to 
power boating from an experience base of small boat sailing, crewing 
racing sailboats and driving 4000 ton Navy destroyers around the 
Pacific, so I had a good deal less 'prejudice' about appearance to deal 
with.  Add to that, we are dealing with that old gearhead Mr. Science 
here, so 'newfangled', 'improved', and 'works better' are music to my 
ears. 

I find that most of us are pretty pleased with our current boats -- 
emotionally invested you might say -- to the point of being a trifle 
defensive sometimes.  Describes me for sure.  I also feel that sometimes 
our attitudes shift and a new car, boat, house, or even spouse becomes 
attractive.  One way or another we've all been there too.  We admire 
loyalty (in others mostly), and at the same time we hold innovation and 
improvement up for approval.  Complicated critters, people.