A 12.5 metre RIB recently completed by Crompton Marine ranks as the biggest RIB built by this Lowestoft based builder and one of the biggest to be built in Britain. This largest RIB in Crompton's Sea Hunter range is destined for a North African country where it will be used by the Customs on coastal patrol work.

This is the first boat which Crompton has built with a wheelhouse, still a relatively rare breed in the RIB market. On this RIB, the wheelhouse is a square, rather boxy affair designed purely to offer the two man crew a degree of protection on long patrols. Forced air ventilators and a de-misting system are used for ventilation. The wheelhouse provides the mounting point for the antennae and the only opening is a watertight door at the rear.

The 24 inch diameter tubes take up a lot of the 3.20 metre beam, but still allow walking space between the tube and the wheelhouse. The foredeck is large and clear apart from stowage bags and bins and will be used to mount armament once the boat arrives on station. The boat has been designed for heavy load carrying with tests simulating an extra 3 tonnes of weight for this.

The hull of this RIB uses the same scalloped multi-chine system used on the smaller Crompton RIBs. The deadrise is 20 degrees and a sheer has been introduced by raising the tube line above the chine at the bow to improve seaworthiness. The tubes are well above the water at rest in light conditions to allow for the load carrying requirements.
Power comes from twin Yamaha 420 diesels each producing 240hp, which are housed in a raised box at the stern. There is ample room in the engine compartment for easy maintenance and the engineering is to a high standard. Yamaha stern drives take the power to the water and on each side of the housing there are drain socks to take any deck water clear.

In the wheelhouse, pedestal seats with fore and aft adjustment are provided for the crew. The adjustment allows comfortable sitting or standing positions with a foot rail provided for sitting. The windows are small, leaving large blind spots particularly on the centreline where an instrument panel further obstructs the view.

Hydraulic power steering is used and the throttle/gear units are the Yamaha standard with the combined trim control in the lever top. On the navigator's side, Crompton has installed the new Simrad Anritsu 3D radar with its remarkably clear screen. This has a GPS feed which also goes to the compact Koden electronic chart unit. A Sailor VHF provides the communications.

The contract called for a range of 800 miles and this has been achieved by fitting two fuel tanks containing a total of 2300 litres.The engines draw from the aft tank and a fuel transfer pump not only moves the fuel, but can be used to trim the boat.

Out on the water, this custom's boat is a joy to drive. The steering is precise, and light enough for long periods at the wheel. The throttles are reasonably well placed on the centre line and it is only the restricted visibility which irritates. The propellers fitted to the boat are relatively small to help with the load carrying requirement and this also benefits the acceleration which is both smooth and quick with the boat powering on to the plane in a very healthy way.

Even with the small propellers, the top speed is still a healthy 38 knots with 1.5 tonnes of fuel on board. The performance is lively, but well under control, and this new design from Crompton should be a viable addition to the Custom's patrol fleet.

Dag Pike


Builder

Crompton Marine (UK) Ltd
109 Colville Road
Lowestoft
Suffolk, NR33 9RF
UK

Tel: +44 (0) 1502 587111
Fax: +44 (0) 1502 587444