Georgs et al: from a pleasure trawler point of view. Most trawler designs
have a wide beam and high freeboard demanded by more living space, operating
space, etc. Abeam seas and following seas have a greater effect on the yaw and
roll. Stabilizers ( mechanical or hydraulic or electric) play their role but
having low down ballast improves the overall motion of the boat (physics,
lower  CG, righting ). Our boat ( Marine Trader 44) in particular has a beamy
stern and is considered semi-planing which is not ideal for ocean cruising. That
is why I had the factory place 8000 lbs of lead in the keel from stem to
stern.  Practical experience has proved this decision to be a wise one.  Even full
displacement trawlers can benefit from ballast. I have had the  opportunity
to cruise out on trawlers with and without ballast. The trawlers  with ballast
by far were more comfortable in all types of seas especially  in the yaw and
roll. Since trawlers of all types do have a keel why not fill it  with ballast
rather than leaving it hollow or solid as the case may be. Regards.  Leonard
Stern, Indifference

Leonard Stern, Indifference wrote, "Our boat ( Marine Trader 44) in
particular has a beamy stern and is considered semi-planing which is not
ideal for ocean cruising. That is why I had the factory place 8000 lbs of
lead in the keel from stem to stern. Practical experience has proved this
decision to be a wise one."

All passagemakers should be designed to some stability requirement, such as
the IMO Offshore Stability requirements, however not all design will require
the same percentage of ballast to achieve the same level of stability.

In general, payload capacity is reduced by each pound of ballast that is
required to meet the stability requirement. Therefore, sans special
contradictory requirements, the measure of a good design is its ability to
meet the stability requirements with minimal ballast. According to Dave
Gerr's equations, for a given hull geometry, power and fuel consumption are
directly proportional to displacement so reducing ballast improves fuel
economy and extends range. In addition, if the reduction in ballast can be
use to increase fuel capacity, range will be increased even more.

Regards;

Mike Schooley

Designing "Portager" a 48' transportable trawler