Review of Bristol 31 XL

The hull is made of fibreglass. Generally, a hull made of fibreglass requires only a minimum of maintenance during the sailing season. And outside the sailing season, just bottom cleaning and perhaps anti-fouling painting once a year - a few hours of work, that's all.

The boat equipped with a masthead rig. The advantage of a masthead rig is its simplicity and the fact that a given sail area - compared with a fractional rig - can be carried lower and thus with less heeling moment.

The Bristol 31 XL is equipped with a fin keel. A boat with a fin keel is more manoeuvrable but has less directional stability than a similar boat with a long keel.

The keel is made of iron. Many people prefer lead keel in favour of iron. The main argument is that lead is much heavier than iron and a lead keel can therefore be made smaller which again result in less wet surface, i.e. less drag. In fact iron is quite heavy, just 30% less heavy than lead, so the advantage of a lead keel is often overstated. As the surface of a fin type keel is just a fraction of the total wet surface, the difference between an iron keel and a lead keel can in reality be ignored for cruising yachts.

The boat can enter most marinas as the draft is just about 1.52 - 1.62 meter (4.99 - 5.29 ft) dependent on the load.

The boat is typically equipped with an inboard Universal Atomic 4 gasoline engine at 30.0 hp (22 kW), which gives a max speed about 6.0 knots.

What is Theoretical Maximum Hull Speed?

The theoretical maximal speed of a displacement boat of this length is 6.7 knots. The term "Theoretical Maximum Hull Speed" is widely used even though a boat can sail faster. The term shall be interpreted as above the theoretical speed a great additional power is necessary for a small gain in speed.

What is a Ballast Ratio?

The ballast ratio for Bristol 31 XL is 33%.

This ballast ratio shows a righting moment that is higher than 14% of all similar sailboat designs. A righting moment (ability to resist heeling) significantly below average.

What is Displacement Length Ratio?

The DL-ratio for Bristol 31 XL is 331 which categorizes this boat among 'heavy cruisers'.

18% of all similar sailboat designs are categorized as heavier. A heavy displacement combined with smaller water plane area has lower acceleration and is more comfortable.

What is SA/D (Sail Area Displacement ratio)?

The SA/D for Bristol 31 XL with ISO 8666 reference sail is 14.5, with a 135% genua the SA/D is 17.6.

The SA/D ratio indicates that it is faster than 27% of all similar sailboat designs in light wind.

The Bristol 31 XL has more rig than 79% of all similar sailboats, which indicates that the boat is significantly overrigged.

Dimensions of sail for masthead rig.

Are your sails worn out? You might find your next sail here: Sails for Sale

If you need to renew parts of your running rig and is not quite sure of the dimensions, you may find the estimates computed below useful.

This section shown boat owner's changes, improvements, etc. Here you might find inspiration for your boat.

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[Ref 1]: ISO 8666 Small craft — Principal data.
[Ref 3]: ISO 12215-5 Small craft — Hull construction and scantlings.