Review of Mercury 18

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.
Some boats has a hull made of Plywood.

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 Mercury 18 is equipped with a long keel. A long keel provide a better directional stability than a similar boat with a fin keel; on the other hand, better directional stability means also that the boat is more difficult to handle in a harbour with less space.

The keel is made of lead. Compared with iron, lead has the advantage of being 44% heavier, which allows a smaller keel and hence less water resistance and higher speed.

The boat can enter even shallow marinas as the draft is just about 0.94 - 1.04 meter (3.08 - 3.38 ft) dependent on the load. See immersion rate below.

What is Capsize Screening Formula (CSF)?

The capsize screening value for Mercury 18 is 2.06, indicating that this boat would not be accepted to participate in ocean races.

What is Theoretical Maximum Hull Speed?

The theoretical maximal speed of a displacement boat of this length is 4.8 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.

The immersion rate is defined as the weight required to sink the boat a certain level. The immersion rate for Mercury 18 is about 42 kg/cm, alternatively 240 lbs/inch.
Meaning: if you load 42 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 240 lbs cargo on the boat it will sink 1 inch.

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for Mercury 18 is 12.6.

Comparing this ratio with similar sailboats show that it is more comfortable than 73% of all similar sailboat designs. This comfort value is just above average.

What is L/B (Length Beam Ratio)?

The l/b ratio for Mercury 18 is 3.39.

Compared with other similar sailboats it is slimmer than 100% of all other designs. It seems that the designer has chosen a significantly more speedy hull design. This type of design is also referred to as 'needle'.

What is a Ballast Ratio?

The ballast ratio for Mercury 18 is 58%.

This ballast ratio shows a righting moment that is higher than 99% of all similar sailboat designs. A righting moment (ability to resist heeling) significantly above average.

What is Displacement Length Ratio?

The DL-ratio for Mercury 18 is 224 which categorizes this boat among 'light crusers & offshore racers'.

21% 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 Mercury 18 with ISO 8666 reference sail is 25.0, with a 135% genua the SA/D is 28.6.

The SA/D ratio indicates that it is faster than 99% of all similar sailboat designs in light wind.

The Mercury 18 has more rig than 62% of all similar sailboats, which indicates that the boat is slightly overrigged.

When buying anti-fouling bottom paint, it's nice to know how much to buy. The surface of the wet bottom is about 8m² (86 ft²).
Based on this, your favourite maritime shop can tell you the quantity you need.

Note: If you use a paint roller you will need more paint than if you use a paintbrush.

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.

Do you have changes/improvements you would like to share? Upload a photo and describe what to look for.

We are always looking for new photos. If you can contribute with photos for Mercury 18 it would be a great help.

If you have any comments to the review, improvement suggestions, or the like, feel free to contact us. Criticism helps us to improve.

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