"VOLUNTEER" is a Rigid Hull Inflatable Boat (RHIB) and was built to our specifications and put into service June 2000. She is a Humber 6.3m Ocean Pro and classified as Class B Offshore which requires that she is designed for extended voyages where winds may exceed force - 8 (46 mph) on the Beaufort Wind Scale and wave heights of 4m +, the vessel must be self sufficient in these conditions.

"VOLUNTEER's" operational area under the MCA Code of Practise is Area Category 3 : 20 miles to sea from a nominated safe haven (Harwich). She is powered by two Suzuki 90 hp four stroke engines giving a useful speed of 43 knots (48 mph) and a range of 70 miles, and CE Load Certified to carry 1700 kgs or 18 persons. Crews, passengers or casualties are PL Insured for £2million.

She operates with a crew of three a Coxn, Navigator and Radio-Operator. All our crews hold MCA / RYA International Certificates of Competence, are first-aid qualified and have vast Local Knowledge.

'VOLUNTEER' - The Concept

The idea of a larger purpose built rigid hulled inflatable boat (RHIB) came about in 1998 after our capable 4m Avon Searider (Guardian) was overwhelmed by seas during casualty working on the notorius Deben Bar and also because we were both now tasked more frequently and much further afield.

The very high specification required for a 'rescue boat' at a reasonable cost, necessitated lengthy research into what RHIB's were available before any order could be placed with a specialist builder. The priorities were for a 6m RHIB with a proven strong deep 'V' hull, yet with a relatively shallow draught for inshore rescue but with no compromising on good sea-keeping qualities. Approved Hypalon fabric inflation tubes (sponsons) with extra heavy duty rubber sheathing around the bows and aft-cone areas. The transom had to exceptionally robust with fore/aft stringers and knees well glassed in and to be of sufficient height to prevent being pooped in following seas, accomodate two engines and have a good angle of deadrise to allow full engine trim. Additional requirements were dry storage, bow Sapmson post/fairlead, substantial towing points, 'Delta' configuration crew seating with 'footals', a strong 'A-Frame' and s/s keel band.

In addition the MCA had just announced their intentions to introduce a Code of Practise for all Open Rescue Boats. The Code would be mandatory for all open rescue boats, including lifeboats, declared or additional facilities to the MCA and would cover the boat, build, engines, operations, management, training and maintenance.
Nevertheless we were confident that we could fullfill this extra criteria and some of the UK's leading RHIB manufacturers were researched and eventually these were whittled down to three companies. One of these invited us to visit it's factory and so five of our committee members travelled up to the Hull based company of Humber Inflatables.  Humber had been producing this robust type of craft for some thirty years and were the UK's leading specialist in this field. Humber's boss Mr. Frank Roffe, who had penned most of their designs said that they had never had a boat returned due to a manufacturing fault. Humbers ethos is 'leading through experience' and that they make everything 'in-house' and sell direct to the public avoiding retailers. As a result their prices were very competitve and their strict quality control demanded that every boat was perfect and durable. At Hull we were treated to a 'rare tour' of the Humber production line. Frank Roffe was very protective about their manufacturing which we respected. We were very impressed with what we saw and the answers to our questions. The best was yet to come and we were invited to water-test a proto-type 'Ocean Pro' RHIB designed for the commercial market. These were usually supplied only to the military, foreign Coastguard Services and the offshore energy sector. We ventured out into the Humber Estuary on a dismal January overcast day with moderate sea conditions. The proto-type had just been prepared to go on test for a leading Powerboat Magazine in an endeavour to introduce it into the growing leisure market. Frank Roffe challenged us to 'fault it if you will' and waved us off from Humbers own private quay. Out in the estuary and five persons onboard we put the 6m 'Ocean-Pro' through its paces is a series of gut-wrenching high speed turns and white knuckle runs into moderate head seas.
Several  attempts were made to purposely swamp the boat by going half-astern into the seas. Even wth the 'Ocean-Pro's' leisure type deck configuration and heavy single Honda four-stroke engine, its overall performance was impressive. Overlooking the sport / leisure type layout, the hull and sponson design, and the overall build quality was exceptional and the potential for a rescue boat application was clear.


The 'Ocean-Pro' hull design was originally developed from a renowned Class 3 offshore powerboat which proved to be a great success in extreme seas. It encompasses high strength, low weight, manufactured top quality, Lloyds approved GRP fabrications, built to a virtually indestructible specification. The deep 'V' multi-chine pedigree hull produces the ultimate in offshore rough water performance, yet gives an exceptional load carrying capacity of 1,625 kg. Advantages of the 'surface effect' hull design are handling and turning at hugh speed and fine entry speeds of 36-8 knots (40 mph) can be maintained in 1m seas. This design provides a very dry boat in that spray from the concave multi-chines is thrown out at low angle, and the hull planes at a low speed giving excellent economy of operation. Humbers high-tech inflation tubes (sponsons) are manfactured from stae-of-the-art French 'Orca' Hypalon Neoprene coated fabric which provides excellent resistance to ultra violet and its inherent ageing characteristics. 'Orcas' rubber base offers superb fire resistance by retaining its properties when exposed to heat, provides high strength resistance to pollution, resistance to tearing or abrasion and the most extreme conditions of weather and rough passage. Furthermore the nature od 'Orcas' Hypalon Neoprene coated fabric allows any necessary repairs to be carried out with speed, precision and safe reliability. Combining this technology with Humbers leading expertise in the concept and field of RHIB design assured us that we had made the right choice and made the best use of our sponsors money. Our wise choice was later confirmed when after a build time of three months during which our liason with Humber Inflatables, re progress reports with photos, changes of specification, additional requirements/fittings was excellent and nothing was too much trouble.



Some three months from the time of placing an order we collected our basic 6.3m Humber 'Ocean-Pro' complete with an Indespension Hallmark Roller-Coaster 5 trailer from Hull. On arrival at Felixstowe she was taken to local suppliers-engineers 'Seamark Nunn' to have her engines and all ancillary work carried out. Sponsorship had previously been arranged with our preferred engine manufacturer Suzuki Marine UK-PLC with a proviso that we have a pair of their state-of-the-art four stroke engines. Thus we had the first ever pair of Suzuki four-strokes engines fitted to any boat in the UK and in their black livery they looked as though they had been especially designed for the 'Ocean-Pro'.

One stipulation made by Humber as part of their sponsorship was that on completion, our fitted out 'Ocean-Pro' was to an exhibit on the Humber stand at the International Dive Show in London, all expenses paid for.  This was the first public showing of an 'Ocean-Pro' at the show and I believed that at least four orders were placed with Humber. Coincidentaly we were close to the MCA Stand and when an ex colleague in the form of Senior Coastguard Comdr Robin Raphael was invited to inspect the 'Ocean-Pro' he commented that she looked superior to any that they currently had in service.

On returning to Felixstowe we had 'Volunteers' civic naming and blessing ceremony carried out by our patron Lady Eva English, Felixstowe Myaor, Cllr Malcolm Minns and the Rev Ken Martin. By early February 'Volunteer' had been registered with the MCA and been allotted her call sign of MWQZ-8. The big day came on 17th February 2000 when she was launched at Suffolk Yacht Harbour for her sea-trials. After a 12 hour engine run-in period we spent three days out in the Hariwch Approaches in a stiff NW Force 6, gusting 7 wind, giving moderate to rough sea conditions some 10 miles offshore at the 'Shipwash'. Without effort 'Volunteer' was safely able to maintain a constant speed of 24 knts (27mph) and was as steady as a rock. Her best speed attained was 36 kts (40mph) which we felt could probably still be improved with a prop change.

Early indications were that the 'Ocean-Pro' had exceptional sea-keeping qualities and would undertake long high speed voyages in big seas with little drama. The deep 'V' variable dihedral hull form gave a dry ride with positive steering (like being on rails) and it proved virtually impossible to induce any skittish chine-wobble. Turning a tight 180 degrees at speed failed to induce any hint of aeration or prop-slip stalling, even with an excessive angle of attack. The 'Ocean-Pro' seemed unaffected bt the twin engines close proximity to each other and the absence of counter rotating props having no discernable bias to handling. In conclusion, the Humber 'Ocean-Pro' was very much a professional RHIB and gave the handling characteristics and feeling of a much larger craft.

Its exceptional load carrying capacity of 1,700 kgs or 18 persons together with all the above qualities made it an ideal Rescue Facility. Mentioned was that the pair of Suzuki engines when fitted looked as though they had especially been designed for 'Volunteer'. The four-stroke range, were introduced in 2000 and were a breakthroguh in outboard technology. Somebody once described the marine outboard engine as 'a combustion and reciprocatin engine trying to tear itself apart'. The Suzuki is far from this and engineered to meet the 21st Century environmental standards, these engines were the first four-stroke outboards to incorporate multi-point sequential electronic fuel injection. They provided the cleanest buring, quietest running, fuel effiecient outboard on the market. Combined with other advanced features like inbuilt engine monitoring systems, duel cooling, electronic dash-pot to reduce engine stress when suddenly decelerating, and a large gear ratio for excellent low-down torque especially useful for a rescue boats many towing duties. Suzuki Marine PLC were extremely pleased with the engines under test on 'Volunteer' and launched a high profile PR Release with photos which appeared in leading Boat Magazines. These 1st Generation engines gave five trouble free years and they clocked up some 8.515 running hours and took; Volunteer' some 14,237 miles. The total cost of 'Volunteer', her trailer, engines and all ancillary equipment through sponsorship was a very reasonable £18,341.


'Volunteer' has Lloyds of London Classification 'B Offshore Rough Water' which requires that she is capable of extended voyages where winds may exceed Beaufort Wind Scale Force 8 with wave heights of 4m +, where she must be sufficient if swamped.

Her licensed area of operation under the MCA Code of Practise is ' Category 3' - 20 miles offshore from a nominated departure point (Harwich). The Cox'n must hold the mandatory MCA/RYA Certificate of Competency.


Further development of ' Volunteer' gained by experience over the last twelve years has included some minor changes to further improve her performance which are detailed here.

As 'Volunteer' was initially kept afloat at all times we soon came up with a remote fresh water engine flushing system. This idea was passed, and agreed by Suzuki Marine and was a simple system adapted from that in use by the MOD. It took the form of a short length of plastic flexi-pipe, a shut off valve and a standard plumbing fitting screwed into the engines cooling system. This simple and cheap but effective system was left in situ and did not impede normal operation. It is interesting to note that most current outboard engines including Suzuki now have a similiar system fitted as standard.

After the first season of operations involving towing in numerous casualties, it was decided to sacrifice 'Volunteers' top speed of 36 kts (40mph) to gain additional low down torque. Therefore the original 13x17 standard aluminium props were changed to 13x919 stainless steel props. Overall we lost some 2knts of top speed but gained on low speed economy and towing torque. Propellor theory is extremely complex and there is little criteria to give the exact propellor size for any particular application. Almost all the 'right answers' are gained by either experience or trial and error.

Our third season highlighted structural failings with 'Volunteers' stainlees steel Navigation Arch or A-Frame. She was originally fitted with a substantial heavy duty double A-Frame costing £545. This had to be sufficiently strong enough to hold navigation lights, a heavy 'Nite Sun' searchlight, 4 Radio/GPS Antennas, 2 emergency blue strobes and 4 s/s dry-box baskets. It also acts as a transom brace able to absorb and impact and the ferocious vibration present on any high-speed craft. My long experience with RHIB's and stainless steel A-Frames has largely been disastrous and I recall many boats in Coastguard service constantly having their s/s A-Frames re-welded or replaced. Stainless steel look sgood and requires little attention, but eventually on a hard worked craft it becomes brittle through temperature change and is too rigid to endure the stresses. During a routine survey in December 2003 hair-line cracks were found around several tube nodes and adjacent to the mounting feet, necessitating emergency repairs. It was then decided to design our own replacement. A-Frame and have it manufactured from aluminium which would be lighter. We consulted Michael Jackson of ' Specialist Welding & Engineering Services' who agreed on our design and recommended a water-pipe grade aluminium as it was thick-walled, malleable/ductile and had a high resistance to corrosion. Our drawing and dimensions proved sufficient and so four weeks later we collected our smart new A-Frame from Michael Jackson (it was a 'Thriller'). It was offered up onboard 'Volunteer' and fitted like a glove but then temporarily removed for painting. It was given an etching coat, two coats of yellow oxide primer and two coats of 'International' Rescue Orange gloss. All the necessary bolt-on fittings were bedded on 'Duralac' anti-corrosive jointing compound for use wherever dissimilar metals are used. Now having been in service for seven years our aluminium A-Frame costing only £300 has no signs of metal fatigue and has proved extremely robust.

Another build modification was that of a substantial staineless steel keel-band for under hull protection at high speeds and for breaching. This required the standard unprotected keel to be faired away to accept a tapering 3" keel-band which was both screwed and 'Sikaflexed' into place. This initially served very well for five seasons until a routine survey revealed that some of the s/s retaining screws were missing their heads. Then on removing more adjacent fastenings it was found that tehy had become 'wasted', much the same as normal keel-bolts are prone to do. So the obvious conclusion was that as 'Volunteer' was moored afloat throughout the summer her keel-band had succumbed to galvanic corrosion. Both the keel and engines were protected by sacrificial ISO 9002 zinc anodes to protect them against this problem. Galvanic corrosion is the deterioration of metal which occurs when dissimilar metals are joined together by a conductor ie, an electronically conductive fluid such as water. This causes a short circuit which generally originates from battery electrical leakage which passes through a hull, spreads in the further exasperated by other influences such as nearby metal objects such as steel retaining wall pipes and other craft being on permanent electrical shore supply. It was decided to have the s/s keel-band removed and replaced with an alternative type of keel protection. The only suitable alternative available was the USA product 'Keelguard' which is basically a rubber strip moulded to the keel with adhesive. Whilst it has a lifetime warranty it is only available in 12ft lengths, thus necessitating a join. Then a local GRP specialist suggested laminating a keel shoe directly onto 'Volunteers' prepared keel. This would cover the entire 6m keel and consist of one layer of 450g biaxial, and four layers of 200g uni-directional 'Kevlar' laminated with epoxy-ampreg which would give an excellent level of protection. This now gives the distinct advantage of being both lighter and maintenance free.

Finally during 2011 'Volunteer' had a ten major refit which entailed having her inflation tub coller (sponsons) replacd, new engines, and her electronics re-wired. Although her sponsons were generally in very good condition and undamaged, they had however worn thin and had already received new cone-ends. It is a common problem that at high speed, the water containing ultra fine sand particles has the very same effect as sand-blasting and had worn away two layers of Neoprene fabric. Which was not entirely surprising as 'Volunteer' had covered some 42,432 miles in ten years. She was taken down to Plymouth where a specialist re-tubing company manufactured and fitted a complete tube coller identical to her original save that this was manufactured from a much heavier denier Neoprene fabric as used by the MOD. 'Volunteer' was also due for a routine engine change so it was decided to take this opportunity to upgrade from 70hp to 90hp Suzuki engines. These new 2nd generation are lighter, more streamlined, more fuel efficient and the Suzuki DF90 is the most compact outboard engine of its class available.

'Volunteer' is a 'Humber' Ocean-Pro rigid hulled inflatable boat (RHIB) Serial No 8305, built to CE Certification EU Recreational Craft Directive Specification. Dimensions: Loa 6.3m Max Beam: 2.34m Int Beam 1.35m Draft 1m (engines inverted).
Air draft 1.26m (antenna down). Weight less engines/equipment 470kg. Max capacity: 1700 Kgs or 18 persons. Fuel capacity: 115 Lts/23 Gallons. Hull type: Medium 'V' variable dihedral multi-chine with Internal buoyancy air tanks. Internal deck layout: 'Delta configuration' helm seat and two crew pods. Max engine rating: one single 200hp or twin 100 hp units.

The 'Ocean-Pro' hull design was originally developed from a renowned Class (3) Offshore powerboat which proved a great success in extreme seas. It encompasses high strength, low weight, manufactured from top quality Lloyds of London approved GRP Fabrications, built to a virtually indestructible specification. The medium deep 'V' multi-chine hull produces the ultimate in offshore rough water performance, yet gives an exceptional load carrying capacity of 1700 kgs. Advantages of the 'surface effect' hull design are handling and turning at high speed and fine-entry speeds of 36-8kts (40mph) can be maintained in 1m seas. This design with its high prow provides an exceptionally dry boat in that spray from the concave multi-chines is thrown out at low angle, and the hull planes at a low speed giving excellent economy of operation.

'Volunteer' has Lloyds Classification 'B Offshore Rough Water' which requires that she is capable of extended voyages where winds may exceed the Beaufort Scale Gale Force 8 with wave heights of 4m+, where she must be self sufficient if swamped. Her licensed area of operation under the MCA Code of Practise is Category (3) or 20 miles offshore from a nominated departure point (Harwich). Her crew must hold the mandatory MCA/RYA Certification of Competency.

She operates under the MCA Code of Practise for all Open Rescue Boats (except club boats) including all lifeboats, declared or additional facilities to HM Coastguard. The Code includes vessel build, engines, equipment, operations, maintenance, training and management.

'Volunteers 'overall weight when fully equipped with onboard fuel is two tonsand she has an operating radius of 70 miles out and return with one hour on-scene. She has two 'State of the art' 2nd generation Suzuki 90hp four-stroke engines giving an economical best speed of 43 kts (48mph).

Navigation equipment includes a standard magnetic compass, a Fluxgate compass, a Garmin GPS/Chart System with 'BlueChart' data area Dover to Humber. 1 Garmin Handheld GPS/Map 'BlueChart' data. 2 Icom VHF/GMDS radios, 3 Handheld radios. 1 Police Airwave radio. 1-406 EPIRB and AIS-B.

Call sign MZFW-8                                            Polce Call Sign FXRB                                MMSI No 32500884

She has a full Safety/Rescue/First-Aid Itinerary ie: wound trauma, splints, burn kits, Oxygen Resus Kit and Hydrostatic Squeeze victim recovery system.