New-York tribune., 1922-11-20
Shipping News and Reports From All Parts of the Wor
Conversion of u. S. Steamer.
To Motorsl,ips Not Feosibl.
Analysis of Costs by Ackerson Shows Vessel. II.
Practically Be Given Away TO Make Change D. n
liable; Great Economies of Diesel Engine pros'

In the most comprehensive and en-
tightening comparison Of motor ships
and steamers that has been given te
the public in some time j. L. Ackerson
vice-presidert Of The Merchants Ship
building Corporation, reaches two i'm
portant conclusions. One Of these ia
that the Diesel engine shows its great
est economy on long hauls, due chiefly
to the saving In cargo space rather
than operating expenses. Another is
that it would not be profitable to con-
vert Shipping Board vessels to the Die
sci drive except at greatly reduced
prices. AS the ships are now held at
$50 ton it would be necessary almost
to give them away to make conversion
profitable.
In support of these statements
Mr.. Ackerson submits a comparison of
the {. towing types of machinery and
ships: Geared turbines with Scotch
boilers, geared turbines with water
tube boilers, reciprocating steara
engines with Scotch boilers, re-
ciprocating steam engines with
water-tube boilers, Diesel 4-cycle
Diesel 2-cycle; as applied to q 5000
ton freighter at ten and one-half knots,
q 7,5Oo-ton freighter at eleven knots,
en s,Ooo-ton freieLtcr at ten and one
half knots, 10,000-ton freighter at
twelve and one-half knots, 10,5o0-
ton tanker at ten and one-haif knots
and a 17,000-ton displacement passen-
ger ship at fifteen knots.
With detailed information on these
vessels, based upon reliable sources,
Mr., Ackerson presented his conclusions
recently at the annual convention of
the Society of Naval Architects and
Marine Engineers at the. Marine Show
on the Selection Of the best kind OF
propelling machinery"
Economy on Diesel Ships
In each instance it was shown that
the annual operating expenses on
Diesel ships are considerably below the
cost of steamers, though the former
have higher first cost.
"Never before has the marine engi-
neering fraternity had SO many differ
ent types of propelling machinery 20
select from, and there is no empirical
formula which can be applied to help
select the best type" said Mr.. Acker-
son. "The problem Of the ship owner
one he has to-day. Among the mary
factors to be considered in deciding
what is the most suitable type are re-
(this is the most important
single factor, for without reliability
other advantages are very much dis
economy in operation, ini-
tial cost and weight, the relative i'm
portance of the last three depending
on the type Of ship under considera-
tion.
From the table Of comparisons the
one outstanding feature is the greater
savings for Diesel-engipe ships in the
iong-yoyage trades, and this is chiefly
due TO the saving OF cargo space re-
quired for carrying fuel oil rather than
to the saving in cost Of fuel oil, operat-
ing personnel and fixed charges. Also.
that for short voyages the DIESEL en-
gine should be given very careful con-
before selection Of the tyne
TO be used is made.
SIT should be noted that, whereas
powers of 1000 to 5000 are possible on
single screw steam installation, il is
necessary TO go to twin-screw installa-
tions for Diesel engines. This incurs
an extra cost in hull construction,
necessitating two shaft alleys, which
cut up the after holds and make it
more difficult to stow cargo, as well
as actually decreasing the cubic Of the
holds,
II have not dealt with the engines
which offer the greatest saving in
space and weight, because up to the
present time none have been built in
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