When Simon Meyjes at Safe Oceans set about designing a new pilot boat, he drew on his extensive operational experience, which included pilotage in shallow waters with steady tidal streams and strong winds. He sought to create the right combination for short fetches and high slamming loads, which are tough on boats and even tougher on personnel — they’re also the conditions that limit the operational capability of typical planing hull pilot boats.
A planing hull can typically endure G-forces a lot better than a human body — anyone who has to go against the grain in shallow waters can attest to the punishment borne at almost all speeds, let alone at the high speeds required for reliable pilotage operations.
Studies show operating high-speed vessels with repetitive vertical G-forces creates injuries, long-term musculoskeletal effects and results in higher operational costs. If crew are comfortable in a boat made to suit the challenging conditions, then operational windows will be broader, with minimal crew downtime.
To build a boat that goes against the conditions often, Safe Oceans had to go against the grain of popular theory to achieve their lofty goals. Several years of research led to a hull design that aimed to deliver excellent performance in rough seas. Safe Oceans chose a round-bottomed displacement hull rather than the flat-bottomed planing hull more typical for the size and desired cruising speed. Using a Low Displacement Length (LDL) ratio hull and a novel approach to sectional shapes, the distribution of buoyancy is longitudinally balanced, creating an excellent ride.
DEVELOPING THE HULL
Safe Oceans drew the hull forms and lines, general arrangements and machinery layouts, while technical references for the hull form and lines came from the National Physical Laboratory. Data for high-speed semi-displacement round bilge hull forms helped confirm the direction was on course for success. Still, it was extensive tank testing that gave rise to the final design.
Three different iterations of the hull were tank tested at 1:10 scale over several months for resistance, trim, dynamic stability and seakeeping performance. The tank test models were constructed of fibreglass by the Australian Maritime College to details provided by Safe Oceans. After more than 200 runs, a great deal of data was obtained.
Wave buoy data collected over five years from the area of operations combined with extensive operational experience to ensure the validity of the data coming out of the tank test for the intended conditions. The total model resistance, model scale speed and forward and aft sinkages were measured. A concerted effort to concentrate weight close to the longitudinal centre of flotation and keep the ends of the vessel light proved to reduce pitching moments dramatically.
The initial tank test results from version one were sent to renowned naval architects Donald L Blount and Associates/Gibbs and Cox USA (major design contractors to US Navy and Coast Guard) for review of the design and the tank testing data. They came back with suggestions for hull ratios, which were implemented into testing models two and three.
Extensive tank testing led to slenderness ratio adjustments, deadrise variations, the centre of buoyancy tweaks and the transom immersion ratio modifications. It resulted in the third iteration seeing a 20 per cent improvement in efficiency compared to version one.
Donald L Blount and Associates reviewed the final design and confirmed it as “fit for purpose.” With that tick of approval, Australian naval architect Andrew MacDonald Smith created the detailed structural fabrication engineering required and construction began at the Gold Coast City Marina and Shipyard.
When the new design emerged to splash down for the first time it garnered some interest as it passed through the shipyard. It looks understatedly capable and the fabrication is exceptional — it’s a robust and well-built boat full of intrigue.
Leaving the Gold Coast Seaway in a 1.5–2m E.S.E. swell, this commissioning test run was more about hunting down less desirable swells with an invincible attitude, rather than dodging them. Once you pass over your first couple of swells, the jostling and need to prepare for impact subsides, and the pleasure derived from the suppleness of the ride can take over.
Maintaining the boat at a nearly horizontal attitude has created a very efficient hull. The fine-entry bow with no hard chine and only a spray rail is uncommon in vessels that are capable of at least 28 knots. It’s quite different to modern high-speed design conventions, but isn’t an unfamiliar design from history — many high-speed, torpedo-carrying boats of World War II employed similar longitudinal buoyancy distribution techniques, utilising slender low displacement length hulls to operate in the challenging North Sea conditions with speed and efficiency, enabling a vast range of operations.
Round bilge sections have produced high ultimate transverse stability together with a soft roll period, which reduces transverse G-forces and aids tracking in a following sea. The longitudinal extremities of the bow and stern are light too, which has helped maintain a desirable running attitude and minimised the vertical forces, with both factors contributing to quite a stable yet natural motion.
Underway, the hydraulically powered active fin stabiliser system provides additional ride comfort. At one stage we went beam on at low speed to the swell. The inshore swell passing over the bar at the Gold Coast Seaway was steep enough to create a significant roll effect, but the impact of the swell was minimal even at low speed. At high speed, the hydraulic fin stabilisers complement the hull’s seaworthiness well.
At speed, running into the conditions, there is no radical change in vertical height crossing the swells. Typically these conditions would have significant rise and fall at these speeds in a planing hull. A combination of the fine-entry and no chine allows the hull to slice through the top of the swell and the rounded hull shape of 21m minimises the rise and fall with a sublime suppleness. It’s truly a remarkable ride. Piercing the top of the waves with a near-horizontal attitude has lifted the stern, allowing higher speeds with lighter, more efficient engines.
Engine room accessibility was a crucial consideration in the design — personnel access from the protected position in the cockpit with a watertight thru-bulkhead door provides safe access when underway. Twin-engine Scania 700hp six-cylinder main engines power fixed pitch propellers through ZF remote mount transmissions. The ability to use lighter six-cylinder engines significantly reduces build and operational costs, while the V-drive transmission configuration optimises the shaft angle and weight distribution, providing ease of access to and rapid removal of all significant components. The machinery space has good standing headroom throughout, and there is easy access to all service points such as belts, shaft seals, fuel filters, seawater strainers etc.
The high bow and surprisingly capable spray rails keep the working deck impressively dry. Safe Oceans has created broad flat working surfaces, and thoughtfully positioned working bollards either viewable from the helm or accessible from protected areas and serviced by a sail track harness system. Forward is a heavy-duty anchoring arrangement that is well protected for on-deck operations or controlled remotely from the wheelhouse.
At the stern, there is a straightforward and effective MOB recovery and resuscitation zone set up for helicopter evacuation. Equipped with high-end SAR electronics, including FLIR and RDF, this configuration is well suited to other applications outside of pilotage.
The air conditioned cabin seats seven crew in suspended comfort, with each chair an impact absorbing, fully adjustable model from Be-Ge of Sweden. Swedish input includes the application of ergonomic geometries developed by Dr Johan Ullman based on two decades of medical and scientific research plus practical experience designing dashboards, steering consoles and wheelhouses. The interior ergonomics and sightlines were 3D modelled by Marsh Duffield Studios to ensure all-round and upward visibility during all stages of vessel operation without the operator having to leave normal helm position.
The ever important, but often underdelivered, night vision considerations have also been carefully studied with an emphasis on night lighting and dimming systems to preserve the night vision of pilots.
OPERATING STRAIGHT OUT OF THE BLOCKS
The first Safe Oceans’ Pilot 21 went straight into operation after commissioning and the commissioning crew were very impressed by the vessel’s all-round performance during its initial 1,500nm delivery voyage from the Gold Coast to Thursday Island. Since going into service, the master has commented, “I conducted my transfer at 9kt today and did not have any troubles at all. Transit at 1,650rpm, 20kt, 65 per cent engine load, approx. 55L/h each side. It held alongside really well, using both motors, and it was a lot easier to break free from the ship using helm only. Vessel handles well, and interaction with the ship was not felt at all. Any weather the vessel has encountered on the head has been smooth and speed has held. The electronics onboard are amazing, and make our life easy and the operation more professional.”
The Safe Oceans 21 is a remarkable ocean-going design, and it is built strong, is efficient and affords significant savings in fuel over existing choices. After several years rumination, Safe Oceans has produced a great boat that is an apt culmination of knowledge, experience and science, and is capable of applying itself to a multitude of commercial applications.
Safe Oceans Pilot 21
$2.65 million AUD
Upgraded SIMRAD navigation suite; FLIR night vision system; RhoTheta RDF system; Wesmar hydraulic bowthruster; Wesmar hydraulic active fin stablisers; back-up Onan generator; back-up air conditioning; and Intersleek silicone below water coatings system.
PRICE AS TESTED
$2.95 million AUD
CLASSIFICATION Design — Lloyds Register Special Service
Registration — AMSA Class 2B Restricted Offshore
MATERIAL Marine Grade Aluminium
LENGTH 21m (69ft)
BEAM 4.69m (15ft 4in)
DRAFT 1.4m (4ft 7in)
DI13 076M with Electronic Management System
TYPE Inline 6-cylinder common rail fuel injected turbo diesels
RATED POWER 515kW (700jp) @ 2100rpm — Patrol Craft Rating
GEAR RATIO ZF 510 RV — 2:1 with Trolling Valve feature
PROPELLERS VeemStar 5 Blade 800mm x 922mm fixed pitch
Safe Oceans Pty Ltd ABN 40601189235
4 Keel Street, Birkdale QLD 4159
E email@example.com or firstname.lastname@example.org
M 0477 799 818