Conventional Pilot Boats The Way Ahead… - Camarc …€¦ · Conventional Pilot Boats-The way ahead…UKHMA Spring Seminar 2007 1 Alastair Cameron, Camarc Ltd. Introduction

UKHMA Spring Seminar 2007

Conventional Pilot Boats

The Way Ahead…

Alastair Cameron

• CAMARC DESIGN •

Avondale, Bullwood Road, Dunoon, Argyll, Scotland, PA23 7QN Tel: 01369 701930 Web: www.camarc.com

Conventional Pilot Boats-The way ahead…UKHMA Spring Seminar 2007 1 Alastair Cameron, Camarc Ltd.

Introduction. The job requirement is simple enough. Deliver a Pilot safely and in good condition to perform their job. So how has Pilot Boat design developed to help meet this requirement and why not one standard design type, in various sizes to meet this demand. Thankfully for us there are multiple factors that enter the equation when purchase of a new Pilot Boat is undertaken. This paper is not about the procurement process and the forces at play. However a quick review of some of the factors will help explain why there is such diversity in the designs we will use to illustrate where the contemporary Pilot Boat currently stands. Each Port usually has a unique combination of the following drivers for the type of Pilot Boat they will use.

• Port History • Port Economics • Environmental Conditions • Transit Distance and Frequency • Maintenance Support services available.

In the beginning….. Camarc’s first Pilot Boat was the ‘Ladybird’, a 12m 28 knot aluminium RIB style boat for Dundee Port Authority. This was back in 1989. A quick lesson on the competing influences on what makes a successful Pilot Boat was given when the Harbour Master enthused to me about the savings in fuel he was making, whilst the Pilot I asked on trip out to a ship how he liked the new boat grumbled that he got bounced about and did not have time to read his paper. She in fact was anything but conventional, and it is relevant to note that many of the designs we produce, which now are perceived as ‘conventional’, are not what one would describe as being in the classic style.

This project led on the Dutch Pilots Association boats which we designed for the Engelaer Yard in the Netherlands. This started with an 18m prototype and lead to a series of 10 off 21m boats. This project in 1993 was probably the single most important in the development of our series of Pilot Boat designs.


The Major Innovations. So what has changed over the past decade and what may you be offered now if you decide to purchase a new Pilot Boat. When I say new, I refer to features that are now mainstream, it does not mean that someone has not tried or been using some of these features over the past decade. Among the changes we see are;

• Fender Systems • Waterjet propulsion • Hull designs with higher speed potential

What about construction materials? I will review construction materials, although we favour a mainstream approach to this and I do not think of this as an area of major innovation at this time. Perhaps in the UK the lessening of the dominance of GRP could be termed a change. Any new arrangements? Layout on Pilot Boats is pretty diverse, and again we do not place that among the major innovations. The UK classic arrangement of aft wheelhouse is very good for optimum comfort. The graph below was developed during the evaluation phase for the Dutch Pilot Boats and shows, what you all probably know already; where the best place to be on the boat is. This chart was useful in convincing some in North America where the classic layout often was a forward wheelhouse with the engine under a large aft deck.


Fender Systems. The one common feature of all Pilot Boats is that they will encounter a ‘controlled collision’ on every operational trip. For many years the rubber ‘D’ fender was king, and there is still a place for that system, especially when used in conjunction with tyres or other additional protection. Camarc have developed a system we call Popsure. This is a development of the Popsafe fender used on the Dutch Pilots Association boats and on some of our other larger designs. The big advantage of Popsure is that it spreads the impact loads over a larger area and this has a consequently lessens the concentration of stresses entering the structure. There are no through hull fastenings, a major maintenance benefit. The system comprises a polyethelene foam section with a polyurethane skin. The foam is completely closed cell and will not retain water if punctured. It has ‘memory’ returning to its original shape after deflection. The second component is the more rigid tube section which takes the main impact and abrasion. One feature of this tube, sometimes criticised, is that it has a relatively low coefficient of friction meaning that ‘stickability’ along side is not as good as tyres or rubber ‘D’.


Fender Systems The Popsure system has been used by Teesport on their 16m Pilot Boats ‘Coatham’ for some 5 years, again on their new ‘Greatham’ and by Falmouth on their new 16m ‘Arrow’. Both these recent craft were built by VT Halmatic.

On the new Pacific Pilots 19m design we are using the top of the fender foam/pu as an extension of the boarding area. The top is level and has a non-slip surface. Although the section has resilience it does not deflect under the weight of a Pilot.

Trelleborg CRP in the UK are the licensed manufacturer of Popsure and at sizes above 450mm in depth (our typical size is 650mm on a 16m boat) the system is exclusive to Camarc designs. We do allow CRP to produce the smaller size for any craft and 3 recent VT Halmatic Nelson 48-50 Pilot Boat for APB Hull were fitted with this system. There are other combinations, ‘Skomer’ the new Milford Haven boat has a large foam/pu fender with aircraft tyres to provide that ‘stickability’ These fender systems are not cheap, but they do reduce the structure repair and maintenance bill in the medium to long term.


Waterjets. This choice of propulsion has come to the fore in recent years. The Dutch boats were our first experience with jets and that has been positive. All of our large North American boats use waterjets, these 22m craft have service speed of around 28 knots. The Numbers.. On a quick tally we have about 21 waterjet boats in service compared to 20 propeller boats. The first of these waterjet craft entered service some 12 years ago, so they have a track record. Currently building are 4 waterjet boats and 3 propeller, so the almost 50-50 mix continues…. We do not expect the balance to shift much in either direction, service speed will be the main driver. One boat you may be familiar with from the UK is ‘Humber Callisto’ a 32 knot triple waterjet boat for APB Hull. Perhaps a step too far too fast? Should you have waterjets for your new boat? The question is usually easily addressed. Do you regularly operate at transit speed of 25 knots or more. If so jets are a serious option. If you want to run at 28 knots plus, we strongly recommend them. Propellers can suffer from cavitation problems of one kind or another at speeds over 25 knots and the waterjet is a very reliable alternative. Waterjets are not as efficient as a good propeller at speed below 25 knots or so but catch up in performance over that speed. The jet absorbs power pretty much independently of boat speed and this prevents overloading of the machinery when boat displacement changes. Cost; The capital cost of a waterjet is higher than a conventional shaft and propeller installation. This is not that significant in terms of overall boat cost, perhaps around 5% for a 16m boat. For the larger boats the cost can increase up to 10% is some cases. We usually specify the next model up to the size that possibly could be used for Pilot Boat application. As the cost of the larger size of jets rises exponentially this can be significant.


Waterjets. Reasons to choose…debris and down time. We have used mostly Hamilton jets on our Pilot Boat designs, they have proved to be reliable, to the extent that the Pacific Pilotage Authority in Vancouver who have two new 19m boats to our design building have elected to stay with waterjets on these boats despite a service speed of 24 knots. With the number of logs in the water over there they find the reduction in down time due to avoiding propeller damage a real benefit.

Waterjet Pilot Boats do present particular challenges for in water person recovery. Many of the boats have side and stern recovery. Stern recovery involves some serious hydraulics for the rescue cradle which articulates down below the water and retrieves the casualty back to deck level.

A client for a 16m design in a very remote area in the Far East has changed from a steel propeller design to an aluminium waterjet boat, the main reason being the debris tolerance of the waterjet compared to the propellers. Their real wish was for a waterjet steel Pilot Boat, that I am afraid we could not grant, jets and heavy boats with a speed of 20 knots do not mix.


Hull Design for Higher Speed. Camarc have our own particular design family for fast Pilot Boats. This is a double chine form, giving a finer entry than a conventional chine boat whilst retaining the roll stability of that hull type. There is no particular difficulty in making a hull design capable of high speed, it is retaining the seakeeping characteristics that is the challenge.

The form is adapted with some minor modifications for the heavier steel 20 knot designs, but the GRP and aluminium designs are a similar generic type.

The resistance curve is particularly suited for waterjet propulsion, there is not an appreciable resistance hump at medium speed; 15-18 knots. This is a useful by product and the hull design was not developed with that in mind. It was one of the reasons for the Dutch Pilots selection of the design.


Hull Design for Higher Speed. The design has high deadrise forward running aft to midships. Stern deadrise is in the 18-20 degrees range. The twin chine rails help control spray. No small craft is going to be comfortable in a seaway at high speed, but operators give us positive feed back on the performance in service.

The Columbia River Bar Pilots, who built the first Camarc 22m design in 2000 have ordered a second boat for delivery early 2008. They have regular 6-10m swells and breaking surf, both boats are self-righting.

Stating the obvious, seakeeping is of fundamental importance for Pilot Boats.


Build Materials So what material are people building these new designs from. The same as usual is the answer. GRP, Steel and Aluminium. Robustness is the common factor required for all these structures. This does not necessarily mean a thick shell or massive overbuild. We like to use deep web frames, especially forward which are well in excess of Class Rule requirements on all our boats. A well integrated structure with good protection is better than a more agricultural approach of throwing material at the problem. GRP; GRP is, or certainly has been, the dominant build material for UK Pilot Boats, certainly the medium sized 13-16m boats. This is something of a historical matter, in the 70’s Halmatic and Tyler’s both provided a range of GRP mouldings suitable for the then new generation of fast Pilot Boats. The tooling for a new GRP boat is expensive, about 25% of the cost for a single craft. This is a natural restriction on the range of designs available.

Holyhead 15m.

In the UK, in fact only in the UK apart from a 12m design in France, the Camarc GRP designs are the 16m VT Halmatic and a new 15m boat by Holyhead Marine Services VT Halmatic 16m Falmouth ‘Arrow’


Steel; Steel works well for larger boats, although we have 12, 14 and 16m designs in service. ‘Skomer’ the new Milford Haven boat is a 19m design with a service seed of 19 knots built by Mustang Marine. ‘Skomer’ doubles as a Harbour Patrol launch in addition to her Pilot Boat duties.

Steel has outstanding toughness and an ability to withstand impact. It does need a good paint system and regular upkeep.

Chinese Port of Tianjin have a 19m steel design similar to the Milford Haven boats currently on the high seas on route from the builder Mustang Marine in Pembroke Dock. A small blip in the balance of manufacturing trade between countries.

Steel is a good material for multi-role craft such as these 14m designs. Speed 18 knots.


Aluminium; This is a versatile build material, and all our overseas higher speed designs are aluminium. Again there is some historical background to this. North America where we have a number of designs in service and build, pretty much use aluminium on an exclusive basis. The Netherlands and the Far East are similar markets, although not as extreme in the proportion of alloy vs GRP.

This is the Pacific Pilotage Authority, Canada , Prince Rupert 22m aluminium Pilot Boat.

17m Aluminium Pilot Boat from the Far East. Unusually this is a high speed propeller boat, 28 knots. Note the conventional ‘D’ rubber fender. Lloyds 100A1 Class.

A typical 16m aluminium Camarc design.

In the UK Mustang Marine are offering our production designs in this material.


Structure, the Choices….. There is no perfect build material. Within the limits of speed steel has a good record of robustness and repairability. The choice of steel is usually not coloured by alternatives. If you want a steel boat you have a steel boat. GRP and Aluminium alloy designs have, in practical terms, equal weight, powering and stability characteristics. Whatever you may hear from the proponents of either material one is not ‘lighter, tougher and stronger’ than the other. They both have their pros and cons. A good aluminium boat structure may be lighter than a clumsy GRP structure and vice versa.

16m Aluminium and GRP cousins. USA and UK

When designing to Lloyds Register SSC Rules with the notation ‘Pilot’ we find similar weights of structure for either material for a given design. Future Materials. The next build material to come into the picture could be advanced composites, Kevlar/epoxy possibly with a light weight core. We like cored structures for light weight and stiffness, but for Pilot Boat hull structure it probably lacks robustness and is difficult to repair. These materials offer lighter weight for a given structural specification, but there is a significant cost premium. For a conventional GRP or aluminium structure the hull, deck and superstructure accounts for about 25% of lightship displacement on a typical pilot boat, so reducing that by 20% (even allowing for lighter engines, less power etc) is not going to yield a quantum leap in performance. No doubt as the cost of these materials reduces we will take advantage of them, probably more for increased strength and robustness than overall radical change. The Dutch 21m boats had a composite honeycomb wheelhouse using board material from the aircraft industry with an aluminium space frame. This has been successful as far as I am aware, but we have not had call to use this again for a Pilot Boat.


Summary This review of the current trends in ‘conventional’ Pilot boat design is not intended to be an in-depth investigation into any particular aspect, it is an overview. The type and options available are many, and reflect the operational requirements of our clients. The alternatives of SWATHs (expensive), Helicopters or catamarans (catamarans?) are out there, but we do not see a shift in the mainstream from the mono hull, not in a timescale that concerns us, if it happens at all. Like every other form of transport the current mainstream designs that we and others produce is different to the previous generations and no doubt the trend will continue as more effective propulsion and material options become available to us at an economic cost. Alastair Cameron. Camarc Ltd. www.camarc.com

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Camarc Ltd, UKtel: +44(0)1369 701930

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Conventional Pilot Boats The Way Ahead… - Camarc …€¦ · Conventional Pilot Boats-The way ahead…UKHMA Spring Seminar 2007 1 Alastair Cameron, Camarc Ltd. Introduction