The design of rudders are usually based on class society rules. The required, minimum rudder area is estimated in relation to the ship’s wetted lateral hull area. Rudder profiles come from old, successful shipbuilding projects. Rudder designs are often developed by another supplier, regardless of the propeller manufacturer. The positioning hull-propeller-rudder is traditionally based on experience from old projects. To balance the rudder torque, the classification rules take the “static” position of the rudder areas in relation to the shaft into account. Dynamic effects from specific propeller inflow, during rudder laying and the influence of different rudder profiles on the
Recently, conmecs investigated the performance of a 50″ pleasure yacht in regular waves. Next to the maximum accessible speed in waves @ a fixed thrust of 30kN, the passenger comfort due to ship motions and the acting loads resulting from slamming pressures were on focus of the project.
The exhaust emissions from ships are not only discussed in terms of GHG (greenhouse gas) reductions. The operators of offshore supply vessels (OSV) are concerned about their technical employees who work primarily on deck and are exposed to the exhaust. In addition to these health matters, yacht and cruise ship operators want to avoid that passengers be disrupted by the smell of exhaust gases.
There are a lot of different energy saving devices (ESD) on the market, e.g. pre-swirl fins, ducts (Schneekluth, Mewis), and post-swirl devices (costa bulbs, rudder fins and hub fins). The suppliers promise efficiency rates, which lie within achieved rates of former projects and the spread is often relatively high, e.g. savings of “2 up to 6%”. For ship owners it is difficult to decide, which device is the best solution for their particular ship design.
According to MEPC.259(68) the pH discharge criteria of scrubber systems can be approved by computational fluid dynamics or other equally scientifically established empirical formulae. Conmecs provides the calculation and documentation according to these requirements. If desired, conmecs can also take over the communication with the associated class society.
About ten years ago the proper ventilation of perishable goods was an issue for some ship owners and operators. Many reefer cargo hold ventilation systems were designed with a weak performance and the cooling units of containers failed during transport due to intake temperatures above the cooling units maximum design temperature. This problem has been solved for many container ships due to the design of ventilation systems according to new regulations, which take into account conservative fresh air volume rates.
Using a RANSE code with a coupled 6-DOF solver, we provide numerical analyses of loads acting on floating structures.
If you need a reliable nominal wake field for the design of your propeller, we provide CFD wake field analysis in model and/or full-scale.
You do not have time to attent an important tank test? The model tank is too far away from your office? You are not sure what to look out for during the tests?
We discovered that a lot of technical reports exists, wherein CFD analyses are not well documented and/ or do not show reliable results. Often clients do not have the in house expertise to correctly interpret the presented CFD data in detail. Many clients are swayed by the ‘colourful pictures’ to accept the provided results without questioning.