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Title: Effect of Spray-Strake on Manoeuvring of a Planing
Hull (Patrol Vessel)
This research describes
a method to improve the manoeuvring performance of a planing hull (patrol vessel) in calm water condition. This involves the use of spray-strakes attached to the hull of the vessel. The
effect of the spray-strake is to reduce the tactical diameter of vessel during turning. Manoeuvring
performance investigations (for turning circle and zig-zag manoeuvres) were carried out using a time domain simulation program.
The hydrodynamic derivatives of the simulation program for surging, swaying and
yawing motions of planing hull with and without spray-strake were obtained through captive model tests carried out in the
towing tank by using a Planar Motion Mechanism (PMM). The results indicate that
the turning circle tactical diameter of the hull with 3 spray-strakes at half-length fitted from amidships to the stem (3SS-Fwd) is favorably
reduced about 3% as compared to the bare hull.
To assess manoeuvring performance quality of a planing vessel fitted with spray-strake, the lift and drag principle
was used to develop the mathematical model that includes the spray-strake. The
method developed involves the setting-up a 3 Degrees of Freedom mathematical model (surge, sway and yaw) using the modular
approach of the Mathematical Modeling Group (MMG). The main parameters of the
spray-strake that have influence on manoeuvring quality can be identified as: location of strake (xSS), breadth of strake (bSS) and projected strake
area (ASS). The accuracy
of the equation was validated using the turning circle and zigzag manoeuvre tests.
On
Going Research
Based on the previus research,
a method to improve the manoeuvring performance of planing hull (patrol vessel) in calm water condition was successfully demonstrated,
this involves the use spray-strake attached to the hull on the vessel. The model were tested using Planar Motion Mechanism
(PMM) in towing tank, especially to obtain hydrodynamic derivatives of the vessel. manoeuvring performance (for turning
circle and zigzag manoeuvres) investigations were carried out using time domain simulation.
Related that reseach, Presentlly
the research objective are summarized in the following:
- To investigate the vessel manoeuvring performance of a planing hull
by using free running model test in open water or large wave basin.
The free running model test setup showed in ficture
below
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