Review of Cobra 850

Both the hull and the deck 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 interior is like most other boats made of teak.
The boat is equipped with 2 cabins, 5 berths, a galley and toilet facility.

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 Cobra 850 has been built with more than one type of keel.

One option is a fin keel. The fin keel is the most common keel and provides splendid manoeuvrability. The downside is that it has less directional stability than a long keel.

Another option is a bilge keel. A bilge keel is a double keel, which allows the boat to be beached. Bilge keels are the most popular keel for tidal waters.

The boat can enter even shallow marinas as the draft is just about 1.45 - 1.55 meter (4.76 - 5.06 ft) dependent on the load. See immersion rate below.

Cobra 850 is typically equipped with an inboard Bukh diesel engine.

What is Capsize Screening Formula (CSF)?

The capsize screening value for Cobra 850 is 1.92, indicating that this boat could - if evaluated by this formula alone - 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 6.3 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 Cobra 850 is about 130 kg/cm, alternatively 730 lbs/inch.
Meaning: if you load 130 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 730 lbs cargo on the boat it will sink 1 inch.

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for Cobra 850 is 24.8.

Comparing this ratio with similar sailboats show that it is more comfortable than 66% of all similar sailboat designs. This comfort value is just above average.

What is L/B (Length Beam Ratio)?

The l/b ratio for Cobra 850 is 2.99.

Compared with other similar sailboats it is more spacy than 58% of all other designs. It seems that the designer has chosen a slightly more spacy hull design.

What is a Ballast Ratio?

The ballast ratio for Cobra 850 is 45%.

This ballast ratio shows a righting moment that is higher than 73% of all similar sailboat designs. A righting moment (ability to resist heeling) just above average.

What is Displacement Length Ratio?

The DL-ratio for Cobra 850 is 325 which categorizes this boat among 'medium weight 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.

When buying anti-fouling bottom paint, it's nice to know how much to buy. The surface of the wet bottom is about 22m² (236 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.

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 Cobra 850 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.