In erstem Bericht wurden die Meßergebnisse des komplexen Viskosität des Wirköles mit dem Schwingviskosimeter betrachtet. In diesem Bericht werden Drehschwingungsmessungen an einem schnellaufenden Dieselmotor gemacht, der mit Viskose-Drehschwingungsdämpfer mäßiger Größe ausgerüstet ist, wenn man die Viskosität des Wirköles im Dämpfer vielerlei wechselte, and daraus wird der Charakter des Viskose- Drehschwingungsdämpfers bei schnellaufendem Dieselmotor ermittelt. Der Schuluβ lautet wie folgend;
1) Je höher die Nennviskosität des Wirköles im Dampfer ist, umso größer wind der Wert der dimensionslosen Federkonstante α des Dämpfers. Deshalb darf man den Effekt des imaginären Terms der komplexen Viskosität im Dämpfer auf keinen Fall vernachlässigen. Und Silikonöl der höheren Visisosität von 30 × 10⁴ cSt verhält sich nicht als Viskose-FlUssigkeit, sondern zeigt emn Verhalten auf, das ebenso näher wie emn elastischer Körper ist.
2) Wenn man auch optimaler Dämpfungsbeding des Dämpfers mit χ²+α²=1.0 oder χ+α=1.0irgend denkt, dann hat dieser Unterschied jedenfalls in der Tat kein Problem. Hier ist x dimensionslose Dämpfungswiderstandskonstante. Aber aus dieser Experimente paßt sich besser, daß man den optimalen Dämpfungsbeding mit χ²+α²=1.0denkt.
3) Es scheint, daß die Meßergebnisse vom Schwingvisikosimeter, d.h. die Wert von tanδ' in den Abb. 8-11 des früheren Berichtes, auf den Original-Viskosedrehschwingungsdämpfer beinahe übertragbar rind.
Diese Ergebnisse sind für Viskose-Drehschwingungsdämpfer bei schnellaufendem Dieselmotor mit Resonanzfrequenzen im Gebiet f=160-490 Hz. Weil das dynamische Verhalten des Silikonöles eigentlich sehr kompliziert ist, braucht man andere Wellensysteme, die in der Resonanzfrequenzen des Wellensystems noch verschieden sind, mit dem Viskose-Drehschwingungsdämpfer zu ermitteln.

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At a recent presentation for the MESJ Mr. Ole Groene of B&W Diesel Copenhagen gave a speach on the issue of‘the L-MC 2-stroke crosshead diesel engines’. At the presentation the basic design criterions as well as a description of the mechanical design of this new engine series was given. Also the performance characteristics and the thereto-dynamical background was outlined.
Latest fuel oil specifications were discussed and also the possibilities for more versatile energy utilization systems for instance for electricity production on board was touched upon.
The basic design criterion for the L-MC engines has been to provide the shipping community with an engine programme for marine propulsion, that has an extraordinary unequalled low fuel oil consumption. This has been fully met by the fact the L-MC engines can have an SFC as low as 118 g/PSh corresponding to more than 50 per cent thermal efficiency. Further the L-MC engines should be able to provide propulsion in a directly coupled form without any need for gearing for any ship. Low RPMS for unequalled propulsive efficiency was to be met, and fully accomplished by the fact the MCR can be chosen even down to 60 rpm.
Mechanically, these criterions have been met by designing an engine with an ultra long-stroke, 3.24: 1 in stroke/bore ratio, using the well proven B&W uniflow scavenging system which is based on 50 years of practical experience.
By utilizing latest design technique and especially on the basis of our experience from uniflow engines in service, it has been possible to design such engines within the physical contour of previous types, thereby keeping weight and size down, and even adding features for further improved reliability.
The L-MC engine series ranging from 56160 PS units down to 2340 PS units covering 6 different cylinder bores from 90 cm to 35 cm utilizes all the inherent benefits of uniflow scavenged engines and the first one tested a 6L35MC has met the thermodynamic design base and several sets are already in service.
All the engines are designed for burning lowest qualities of bunker fuel, i.e. BS MA 100 class M9.
At present more than 100 L-MC engines are on order, confirming the success and need for such ultra-high economy engines.

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This paper reviews the current and future marine fuel oil quality in terms of normal fuel inspection test items.
Increasingly, straight run residual fuels are being replaced by high conversion residual fuels due to further reprocessing of straight run residual fuels in order to satisfy the increased demand for middle distillate fuels. Generally, a high conversion fuel has a higher density, a lower stability reserve and a higher level of contaminants than a straight run fuel with the same viscosity.
Throughout the history of residual fuels usage in motor vessels there have always been considerable variations in the properties of fuels, both with time and from different locations. Efficient combustion depends particularly on the design and condition of the plant, and ships' engineers who regularly faced with variations in fuel quality can obtain clear and economic operation by careful attention and adjustments to fuel quality.
Recommendations are given on motor vessel fuel handling and fuel system designs.

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