Crew safety is a key parameter for any seagoing mission. Although today’s standards are high, occasionally people go overboard while working on deck. In this case the probability of survival remains low. The joint research project “AGaPaS” [1] aims to significantly increase the chances of survival for a drifting person. Its main objective is to develop a self activating, partially autonomously operating rescue system, able to search, find and rescue people gone overboard. A crucial part of the system is a remotely operated vessel, which is released by free fall from a mother ship. This paper focuses on the hull optimization of this rescue vessel, considering various aspects. The rescue operability has first priority and leads to numerous system specifications such as main dimensions. In addition, adequate seakeeping behaviour is a prerequisite for the successful recovery of a person in distress. This includes small relative motions between the vessel and the drifting person. Moreover, the vessel’s free fall characteristics are to be analyzed. Here, particular interest has been laid on the reduction of the peak acceleration as well as on transferring the vertical velocity into a horizontal motion, in order to minimize the risk of a collision with the mother ship. Various hull geometries have been investigated by means of numerical methods as well as model tests leading to the final hull design of the unmanned AGaPaS rescue vessel.

There is a multitude of seagoing missions such as rescue missions, coast guard and pilot duties, whose success depend on ship-deployed boats. Launching these boats from a mother ship or recovering them by special deployment systems in a broad range of environmental conditions are key operations for a successive mission. In recent years, new boat deployment systems, promising better operational availability at high sea states, have evolved beyond the traditional side-davit system with dual falls. These new systems deploy their boats via stern ramps integrated into the transom of the mother ship, for example seen at numerous rescue cruisers around the world. This paper presents two different boat deployment systems. After a short discussion of the disadvantages of side-davit systems, a new type of a stern boat deployment device, the so called Janssen Docking System [1], is introduced. This system is equipped with an articulated ramp hinged to the stern. Whereas launching operations are less critical, the recovery of boats is quite hazardous. For this operation mode structural forces on critical areas as well as the relative motions between the ramp and the small boat are systematically investigated in model tests. Based on the results of these sea keeping tests the feasibility of the system has been analysed and improvements are recommended. As a second system a floodable dock integrated into a mother ship is presented. For launching and recovering small boats at high seas the swell inside the dock and the resulting relative motions between boat and dock ship are investigated. This leads to critical flow conditions inside the harbour in terms of sloshing waves with heights up to 3 meters. The analysis of local flow phenomena inside the dock dependent on the motion of the ship in a given sea state are the basis for the development of an optimized dock shape. Therefore an existing nonlinear numerical method for unsteady viscous computation based on Volume of Fluid (VOF) methods and Reynolds Averaged Navier Stokes Equations (RANSE) is used to simulate these phenomena. The time domain calculation allows to change local dock shapes systematically for further improvements. To validate the numerical solution the calculated results are compared to sea keeping tests at model scale. The paper concludes with a perspective for the further development of the dock shape.

The joint research project “AGaPaS” (Autonomous Galileo-supported Rescue Vessel for Persons overboard) aims to significantly raise the chances of survival for people who have gone overboard. Its main objective is to develop a self activating, partially autonomously operating rescue system, able to search, find and rescue a drifting person [1]. A crucial part of the system is a remotely operated vessel, which is released by free fall from a mother ship. This type of launch offers a minimum response time but comes with the disadvantage of high loads for the rescue vessel and its equipment. A particular challenge is posed by the catamaran shaped hull, being dropped from a cruising ship. The goal is to find an optimum in the occurring accelerations and pressure loads applied to the hull. While the pressure loads have a direct impact on the strength of the hull, the accelerations mainly affect the boat equipment and its mountings. The hull optimization has already been conducted [2], therefore, this publication focuses on the identification of favourable launch parameters. Within the scope of this investigation crucial parameters such as cruise speed, drop height and launch angle are varied. All free falls are analyzed by means of computational fluid dynamics (CFD), whereas selected cases are validated by experimental data.

For the design of FPSOs the vertical bending moment is a key parameter to ensure safe operation. If analyzed at water line level, however, the unknown influence of longitudinal forces may distort the results. Hence, a segmented FPSO model with midship force transducers at two levels is investigated in various deterministic wave sequences to identify the vertical bending moment and its associated neutral axis as well as the superimposing longitudinal forces. It is shown that the neutral axis is far below the water line level, with the consequence, that extreme cyclic loads at deck level would be expected. However, as the associated longitudinal forces — even if significant — generate a counteracting moment, this effect is largely compensated. Both, frequency- and time-domain results are presented. With frequency-domain analysis the profound data for the standard assessment of structures, concerning seakeeping behaviour, operational limitations and fatigue are obtained. In addition, time-domain analysis in real rogue waves gives indispensable data on extremes, i.e. motions and structural forces.

For any seagoing mission such as rescue missions, coast guard or pilot duties, crew safety is a key parameter. However, in extreme situations there is always a residual risk for crew members to go overboard. In this case the probability of survival is relatively low until today. This paper presents the joint research project “AGaPaS”, which is aimed to significantly raise the chances of survival for a drifting person. The main objective is to develop a self activating, partially autonomously operating rescue system being able to search, find and rescue people gone overboard. The project accounts for all aspects of the rescue process including: • the life jacket equipped with various sensors and a radio transmitter; • the construction of the rescue vessel; • a real time positioning system for the rescue vessel based on Galileo; • a recovery unit for the person overboard; • a recovery system for the rescue vessel; and • the integration into a conventional bridge system. A crucial part of the rescue process is the recovery of the remotely operating vessel including the retrieved person by a mother ship. Similar problems have already been investigated by the Technical University Berlin before [1], [2]. Whereas launching operations are less critical, the recovery of a boat, especially in severe weather, is a challenging task. Therefore, strength analyses, as well as relative motions are to be systematically investigated using model tests and numerical simulations considering a coupled system consisting of the mother ship with an articulated recovery system and the rescue vessel. Furthermore, the manoeuvrability of the rescue system is evaluated at high sea states. As a result of the research project a fully operational testing model at full scale is designed and built.