The High-speed planing vessels are employed in racing, rescue, and police operations. But they are also often used for recreational purposes these days. The majority of planing vessels are under 30 meters in length, making them comparatively small in size. Considering the significant amount of recreational usage of planing crafts, remarkably minimal research has been conducted on the subject. A vessel is considered to be planing when the hydrodynamic pressure loads
significantly exceed the hydrostatic pressure loads. As a result, the trim and lift of the vessel are predominantly determined by the hydrodynamic pressure. There are no clear- cut conditions for planing occurrence; however, a common threshold is defined by the dimensionless length Froude number
Coronet DC 21ft Hull
Coronet DC 21ft hull was optimized. It was one of the best boats in the Nordics in the 1960s, the Coronet 21 DC was already a motorboat legend in its first year of operation. The first Coronet 21 DC was put through a test drive in 1965, and the yard was established in Copenhagen in 1951.
This hull has a 6.4m length and 2.3m beam
Hull Modification: Steps and Extension
A total of six variations were created for steps located at the mid, forward, and back regions and the remaining three extensions in the hull are based on extended hull length.
The results of CFD were compared with the Maxsurf Results for validation purposes in the absence of experimental data. The Below figures showing the hydrodynamic pressure contours on the bottom of hull
Extended hulls, particularly Ext-1, offer the greatest reduction in resistance. While stepped hulls reduce resistance compared to BH, they don’t match the efficiency of the extended hulls, with SB3 showing the best performance among the stepped designs.
Sinkage remains relatively consistent across all hull modifications. Extended hulls, particularly Ext-1.5, show a slight improvement in reducing sinkage, but the overall differences are minimal.
Extended hulls have a considerably larger wetted surface area, which increases with hull length. This contributes to better planing but may also lead to slightly higher resistance at greater lengths. Stepped hulls reduce the wetted surface area, which is beneficial in lowering drag, especially in the case of SB3.
Extended hulls show a significant improvement in reducing dynamic trim, with Ext-1.5 performing the best. Stepped hulls, especially SM1, result in higher trim angles, which may offset some hydrodynamic gains.
