[PUP] PPM

[hannu venermo]

Not at all, Georg.
> The other thing that Hannu Venermo got wrong was that Idlewild was comfortable.
>
>   
Boats, and most complex systems, are a combination of factors.
The comfortable hulls are *heavy*, ie fairly deep draft, as well as slim 
and long, as I said in my post.
Please do not mis-quote ....
Idlewild, being lightly built in aluminium and made light for other 
reasons, valid for the intended purpose (portaging), is what made it 
roll easily.
(I did misremember it being built in steel and not alu - I do apologise 
for the un-intended error that however does not seem to me to be material).

Hull comfort is mostly a function of relative draught, only very far 
less a function of form, ie hull shape.
The most comfortable hull in the world is a submarine.
The next most comfortable one is a vlcc crude oil carrier when full - 
90% of the hull is underwater.

The unsailboat is according to the designers, the Dashews, 
internationally acknowledged as master designers and builders with 40 
years experience, and backed up by objective gravitometric sensor data, 
far more comfortable than the best sailboats they built.

A long slim hull, deep draft, ie. a very good passagemaker, is the most 
comfortable hull form.
A light hull, that sits mostly out of the water, is very "frisky" and 
rolls far, far more easily.

Expending energy can somewhat mitigate rolling, be they 
flopper-stoppers, stabilisers, paravanes, gyroscopes or whatever.
Their need is mostly a function of the relative displacement of the 
hull, ie how deep it sits in the water, and of course the weather 
conditions.
Deep draft hulls do not, in general, necessarily need stabilisers.

I am not saying someone should not fit them - if you have the money, 
stabilisers are certainly nice to have.
However, a good passagemaker hull has little real need for them, and 
they are an additional comfort item. Their need should be based on 
personal preference.

The real trawlers that do go out to sea all the time (re: see the series 
"Most dangerous catch") do not have or use stabilisers or paravanes.
They are also somewhat comfortable when empty and  very comfortable when 
full (very heavy) - they are too full in the body, and inefficient, to 
be really good as the perfect passagemakers, as their main function is 
to carry large amounts of cargo ie load, and motor fuel vs hull 
efficiency has little effect on their operating costs. Of a 300k$ load 
of fish for a single trip, 20k$ might be spent on fuel, 5k$ on food !, 
and 10k$ on general repair & maintenance. Reducing the fuel by 50%, an 
impossible amount, would not affect appreciably their profits but would 
very much affect their speed.

The commercial trawlers need to catch large amounts of catch, move very 
heavy loads, and sail in very heavy seas - all of these factors mean 
that their engines are 4-6 times larger than they would need to be in an 
efficient passagemaker.