Access
Having the ability to access the boats many systems is important for liveaboard cruisers. The yacht designer Steve Dashew once stated “90% of maintenance is access”. Having a dedicated mechanical space to work on the engine, generator, autopilot, and watermaker is much better than reaching around furniture and bulkheads to unseen spaces. Purpose built cruisers like Amels, Valiants and Outbounds are designed emphasizing this feature.
Stern
For safety reasons, a stern with a swim platform in the transom is preferred. The ease of getting crew back in the boat after a MOB situation is very important. The platform also serves as a great place to access the dinghy. Moderate beam to the length is also desired. Besides adding to hull stability as mentioned previously, finer ends benefit what is known as the prismatic coefficient or hull efficiency. The wider the ends, the more sail area is required to power the boat. This is why a longer boat with a skinny beam has a much smaller sailplan than a comparable LOA boat. Wide sterns are beneficial on planning hulls but produce no sailing benefits for displacement cruising boats. The wide sterns on a displacement boat do not track as well downwind and in a stiff breeze tend to plow the bow. The wide sterns have now reached the point that it has become very common to have double rudders to keep them under control. Head on, dual rudders are not protected by the keel which could be a potential safety issue. It should also be mentioned that large, wide open cockpits are a joy at anchor, but are unsafe in a rough seaway where the crew has limited options to cross brace themselves or have good protection from rogue waves.
Rudder
Traditionalists will argue a blue water cruising boat should have a full keel with the rudder attached to the keel. This is the slowest and least maneuverable underbody but gives a great deal of rudder protection. Full keels are very challenging to back or turn at a dock under power so a bow thruster is almost a requirement. The rudder on a skeg is the next level of safety. Partial skegs are the best option for both safety and maneuverability. Lastly, we have the spade rudder. Most boats made today have spade rudders but not all are created equal. A spade with a thick carbon fiber rudderstock (impervious to rust) vs stainless steel is the desired option. If the propeller is close enough to the spade, a bow thruster is not needed. Eliminating two large holes in the bow is good for bluewater voyagers.
Keel
There are two types of keel construction, bolt-on and encapsulated. There is a hybrid of the two with a fiberglass hull section tapered to the middle section of the keel with ballast bolted on at the bottom. For safety reasons the encapsulated and hybrid are preferred because they are best to absorb hard groundings. There have been documented cases of keel bolts that have failed either due to poor design or corrosion leading to sinkings. Lead weighs more than iron so it is the metal of choice for ballast. Unfortunately, lead is not used in most production boats because it is much more expensive and this adversely effects the ballast/displacement ratio. One also needs to keep an eye on draft. Many of the high end monohulls such as Oyster, Swan, and Hallberg Rassy draft over seven feet targeting European markets which may limit your cruising area but provide excellent stability and windward performance. Some boats such as Bristols and Hinckley’s have centerboards which can be problematic to service if a problem occurs unless on the hard. The lifting keel of the Southerly line is great alternative but the availability and price of these models put them out of reach of most cruisers.
