Review of Top Hat 25 Mk I

Both the hull and the deck is made of hand laid fibreglass. Generally, a hull made of hand laid 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 is equipped with one cabin, 2+2 berths, a galley, 159.0 liter fresh water capacity and toilet facility.

Note: the boat has also been sold to be self-made/-interiored, which means that the quality of each boat may vary.

The Top Hat 25 Mk I is built 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.

Full keel

The Top Hat 25 Mk I is built with a long keel. A full 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.

Top Hat 25 Mk I can enter even shallow marinas as the draft is just about 1.30 - 1.40 meter (4.27 - 4.57 ft) dependent on the load. See immersion rate below.

An outboard motor is often used on this boat. In that case the boat will typically require a power of 5 - 6 hp, alternatively 112 - 135 lbs thrust if you prefer an electrical motor. Electric outboards are becoming popular for sailboat owners who want clean instant power with less noise and no exhaust fumes.

What is Capsize Screening Formula (CSF)?

The capsize screening value for Top Hat 25 Mk I is 1.80, 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 6.1 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 Top Hat 25 Mk I is about 102 kg/cm, alternatively 572 lbs/inch.
Meaning: if you load 102 kg cargo on the boat then it will sink 1 cm. Alternatively, if you load 572 lbs cargo on the boat it will sink 1 inch.

What is Motion Comfort Ratio (MCR)?

The Motion Comfort Ratio for Top Hat 25 Mk I is 24.6.

What is L/B (Length Beam Ratio)?

The l/b ratio for Top Hat 25 Mk I is 3.12.

What is a Ballast Ratio?

The ballast ratio for Top Hat 25 Mk I is 47%.

What is Displacement Length Ratio?

The DL-ratio for Top Hat 25 Mk I is 289 which categorizes this boat among 'medium weight cruisers'.

SA/D (Sail Area Displacement ratio)
Indicates how fast the boat is in light wind:
- Cruising Boats have ratios 10-15
- Cruiser-Racers have ratios 16-20
- Racers have ratios above 20
- High-Performance Racers have ratios above 24
Sail-area/displacement ratio (SA/D ratio): 14.51

When buying anti-fouling bottom paint, it's nice to know how much to buy. The surface of the wet bottom is about 18m² (193 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 is reserved boat owner's modifications, improvements, etc. Here you might find (or contribute with) inspiration for your boat.

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

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