Greg Copp examines a popular veteran of the seas that comes in many guises …

Ageless though semi-displacement boats inevitably are, few have heritage like the Mitchell 31. This boat, designed by Alan Hill, was first launched back in 1969. The first version, known as the mk1, was built as an offshore fishing/diving cruiser with a long cockpit and short wheelhouse. In 1984, the mk2 was born, offering further refinement but still very utilitarian. However, with the launch of the mk3 in 1991, the Mitchell 31 became much more credible as a pleasure boat, as the wheelhouse was extended, giving the boat much more realistic accommodation.

Unlike the round-bilge designs of some of her contemporaries, the Mitchell 31 has wide, flat chines aft with a sharp forefoot leading to a deep keel. If you view the hull out of the water, it is nearly flat across the stern. The deep keel is ideal for the single-engine installation that many of these boats have, providing protection for the rudder and the prop. The flat aft sections not only serve to provide the lift required for semi-displacement speed, but give the boat stability at trolling speed and at anchor. Many of the earlier boats were powered by single 180hp Ford Mermaid diesel engines, with 225hp Perkins Sabre diesel engines being introduced later in both single and twin installations. However, there is no hard and fast rule here as there are now many different power options to be found in the Mitchell 31. Retrospective repowering has resulted in many older boats sporting newer engines such as single 320hp Nannis and even twin 125hp Yanmars.

Many Mitchell 31 mk3s were bought by the police, generally with twin 225hp Perkins engines, and should be capable of around 20 knots. However, single-engine boats have proven more popular in the private sector as a single 225hp Perkins will provide a 14-knot top speed and a frugal 10-knot cruising speed. The 2009 boat featured in this article belonging to Dean Hall has a single common-rail injected 225hp Perkins Ti engine. This, Dean told me, is blissfully cheap to run at 10 knots, which, after having owned an Azimut 42, makes boating realistically affordable in the post-derogation age.

As is to be expected, seakeeping is a Mitchell strong point. The sharp forefoot will plough through pretty much anything, Dean told us. After having owned bigger boats, he wanted a smaller boat that would give him reassurance above its size. On one occasion, heading east back into the Solent through the Needles channel, he had to deal with an easterly force 6 against the tide, which, given the location, meant a tall, sharp, angry sea. His boat casually ploughed on through without a complaint.

The build quality, like its bigger contemporaries from Nelson and Aquastar, is of a high standard. Though most are now used as pleasure boats, many started life in commercial use. Consequently the fit-out will often be spartan, though very practical. Ex-police mk3s will have three heavy-duty shock-absorbing seats in the wheelhouse. Many of the mk2s have an MOB winch on the starboard side. All the deck and cockpit hardware is seriously heavy-duty and storage beneath the cockpit is plentiful. Engine access is designed for rapid access via a hinged cover in the cockpit. Internal accommodation on the mk3 is good, courtesy of a bigger wheelhouse.

Dean’s boat was the 2009 SIBS show boat, and being built as a pleasure boat from the outset the wheelhouse has a small saloon with dinette. The high-quality oak joinery sets it apart from its commercial cousins, though the internal layout forward is much the same. A compact galley sits to starboard complete with hob, sink, microwave and oven. In order to accommodate a full-size fridge, it is built in under the navigator’s seat. The heads sits opposite the galley and a double berth cabin is located in the forepeak. The cockpit not only has a second helm position but, with its covers up, provides a substantial extension to the accommodation if need be.

If you are looking for a middleweight semi-displacement sea warrior, then the Mitchell provides a great alternative to the likes of Nelson and Aquastar. However, its greatest appeal is its variety in terms of fit-out, engine options, age and price.

Points to consider


The main thing to consider is engines. Not many Mitchell 31s will have the original Ford Mermaid engines, but if you do consider a boat fitted with a Ford engine, check its service history and certainly have a mechanical survey. Also consider the availability of spares. If you are looking at a Perkins-powered boat, spares are not a problem and these engines are dependable, but have them surveyed nevertheless. If you are looking at an ex-police boat, it will have clocked up a lot of hours but will have been meticulously serviced on a very regular basis, and should prove a good buy as a result. Do not let the hours logged put you off as boats are not like cars and thrive from regular use. Any boat that has been repowered, and there will be quite a few, will have a new lease of life. The extra premium that a repowered boat will attract is worth paying, especially if you intend to do some long offshore passages.


No less important than the engines is the hull. Osmosis, though not a known problem for these boats, is something to watch out for on a boat that has spent long periods afloat. There is also the issue of internal structural damage (stringers and bulkheads), as capable sea boats tend to get used in earnest in rough weather.

Price range

These boats have a very wide price range, from £20,000 to £100,000, due to their long production run, engine options and model changes. Consider carefully what you intend to use the boat for and, importantly, the accommodation you will realistically need. Due to the bigger wheelhouse on the mk3 you get a genuinely usable amount of accommodation up top, which otherwise limits its use as a pleasure boat.


If you go for a single-engine boat, a bow thruster would be wise. Ideally, like the boat featured here, both bow and stern thrusters will make berthing a breeze.

Data file

  • Designer: Alan Hill
  • Berths: 2
  • Cabins: 1
  • Hull type: Semi-displacement
  • Current values: £20,000 to £100,000
  • Length overall: 31ft (9.45m)
  • Beam: 11ft (3.35m)
  • Draught: 2ft 7in (0.79m)
  • Displacement: 5 tonnes (light) depending on engine options
  • Fuel capacity: The mk3 featured in this article has 2 x 100-gallon tanks
  • Water capacity: 40 gal (180 litres)
  • Cruising range: Up to 380 miles with a 20% reserve at 10




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