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Kansainvälinen merenkulkujärjestö IMO käynnisti prosessin vuotovakavuussäännön kehittämiseksi sillä Euroopan meriturvallisuusviranomaisen EMSA:n vuonna 2008 teettämässä tutkimuksessa oli havaittu vakavia turvallisuuspuutteita voimaan tulevassa Solas 2009 vuotovakavuussäännössä. Tämän jälkeen matkustaja-autolauttojen vuotovakavuutta on tutkittu laajasti ja vuotovakavuussäännön muuttamiseksi on esitetty useita eri vaihtoehtoja. Näistä ehdotuksista ei kuitenkaan päästy yksimielisyyteen, joten IMO:n SDC-alakomitean työryhmä laati kompromissiehdotuksen R- ja A-indeksien muuttamiseksi. IMO:n jäsenvaltiot pystyivät hyväksymään Solas 2020:nä tunnetun sääntömuutoksen. Muutos kohottaisi merkittävästi alusten turvallisuustasoa vuotoon johtavassa yhteentörmäystilanteessa. Toisaalta aluksen suunnittelusta ja rakentamisesta tulisi aikaisempaa haastavampaa, mikä taas kasvattaisi kustannustasoa. Tässä työssä tarkastellaan tapaustutkimuksena sääntömuutoksen vaikutusta nykyaikaisen, Itämerellä operoivan matkustaja-autolautan vesitiiviin osastoinnin suunnitteluun. Työn tarkoituksena on selvittää, onko meriturvallisuuskomitean hyväksymä sääntömuutos riittävän vaativa, jotta sillä voidaan korvata matkustaja-autolautoille nykyisin voimassa oleva Tukholman sopimus, direktiivi 2003/25/EC, jolla käsitellään alustyypille ominainen, vettä kannella –tilanne. Tutkimusten tuloksena havaittiin, että Tukholman sopimus on edelleen määräävin vuotovakavuussääntö, joka tulee asettamaan rajoitukset matkustaja-autolautan vesitiiviin osastoinnin suunnittelulle., International Maritime Organization (IMO) started a development process with its damage stability regulations. Research study in year 2008 tendered by European Maritime Safety Agency EMSA found significant defects in Solas 2009 damage stability rules. Since then damage stability of passenger ferries has been widely studied and variety of proposals on how the damage stability rule should be updated have been given. Because none of the proposals were unanimously accepted by IMO member states, SDC sub-committee’s working group drafted a compromise proposal for updated R- and A-indices. This SDC proposal, which is known as Solas 2020, is widely accepted between IMO member states. This update to damage stability regulation would significantly increase the safety level of passenger ships in collision accidents. On the other hand, design and building of new vessels can be more challenging than before, which will affect cost level. Effect of the updated damage stability regulation to design requirements of the watertight compartmentation of modern Baltic ro-ro-passenger ferry is studied in this thesis. Goal of this study is to find out if safety level this updated damage stability rule high enough that current Stockholm Agreement, directive 2003/25/EC, which takes into account ferry specific ‘Water-on-Deck’ situation, can be withdrawn. As a result it was found that Stockholm Agreement is still the most governing damage stability rule, which will set requirements for design of watertight compartmentation of ro-ro passenger ferries.

The cold dark matter (CDM) scenario generically predicts the existence of triaxial dark matter haloes which contain notable amounts of substructure. However, analytical halo models with smooth, spherically symmetric density profiles are routinely adopted in the modelling of light propagation effects through such objects. In this paper, we address the biases introduced by this procedure by comparing the surface mass densities of actual N-body haloes against the widely used analytical model suggested by Navarro, Frenk and White (NFW). We conduct our analysis in the redshift range of 0.0-1.5. In cluster-sized haloes, we find that triaxiality can cause scatter in the surface mass density of the haloes up to sigma(+) = +60 per cent and sigma(-) = -70 per cent, where the 1 sigma limits are relative to the analytical NFW model given value. Subhaloes can increase this scatter to sigma(+) = +70 per cent and sigma(-) = -80 per cent. In galaxy-sized haloes, the triaxial scatter can be as high as sigma(+) = +80 per cent and sigma(-) = -70 per cent, and with subhaloes the values can change to sigma(+) = +40 per cent and sigma(-) = -80 per cent. We present an analytical model for the surface mass density scatter as a function of distance to the halo centre, halo redshift and halo mass. The analytical description enables one to investigate the reliability of results obtained with simplified halo models. Additionally, it provides the means to add simulated surface density scatter to analytical density profiles. As an example, we discuss the impact of our results on the calculation of microlensing optical depths for massive astrophysical compact halo objects in CDM haloes.

We discuss the recent discovery by Oppenheimer et al. of old, cool white dwarf stars, which may be the first direct detection of Galactic halo dark matter. We argue here that the contribution of more mundane white dwarfs of the stellar halo and thick disc would contribute sufficiently to explain the new high velocity white dwarfs without invoking putative white dwarfs of the dark halo. This by no means rules out that dark matter has been found, but it does constrain the overall contribution by white dwarfs brighter than MR 16 to significantly less than1 per cent of the Galactic dark matter. This work confirms a similar study by Reyl, Robin &Crz.