The Block Island 40 is modestly canvassed and unhurried, with a steady, comfortable ride offshore.
Hull Speed
The theoretical displacement-mode speed limit — determined by waterline length, not engine or sail power.
A displacement hull pushes a bow wave whose speed is limited by the waterline length.
With a waterline of 27.5′, the Block Island 40 tops out around 7.0 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √27.5′ LWL = 7.0 kts
Performance Ratios
Racing handicap, sail-carrying power, stability and comfort — and what each one actually tells you about a day on the water.
SA / Displacement
13.7
Modestly canvassed — a comfortable, unhurried cruiser.
Ballast / Displacement
23.8%
Light ballast — tends to be tender; reef earlier than the numbers suggest.
Displacement / Length
451
Heavy displacement — a slow, steady, seakindly hull.
Comfort Ratio
39.0
Good offshore comfort — steady enough for multi-day passages.
Capsize Screening
1.71
Below the 2.0 offshore threshold — acceptable for ocean passages.
Pounds/Inch Immersion
7lbs
Weight needed to sink the hull one inch — loading sensitivity.
Motion & Offshore Suitability
Two ratios that matter most when you're planning passages — how the boat feels in a seaway, and whether the hull geometry is suitable for open ocean.
Comfort Ratio
39.0
Good offshore comfort — steady enough for multi-day passages.
Under 20 — Snappy, racing motion
20–30 — Acceptable coastal
30–40 — Good offshore comfort
Over 40 — Very comfortable offshore
Capsize Screening Formula
1.71
Below the 2.0 offshore threshold — acceptable for ocean passages.
Under 2.0 — Acceptable for offshore
Over 2.0 — Coastal / protected waters
PHRF Fleet Position
Where the Block Island 40 sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Cruiser/Racer 90–150
Cruiser 150–210
Heavy Cruiser 210–300
Cartwright 40
153s/nm
Nevins 40
177s/nm
Dickerson 40
197s/nm
Newporter
209s/nm
Estimated Speed by Wind
Rough boat speed estimates at different true wind speeds and points of sail — derived from hull speed, SA/D, and displacement, not measured polars.
| Point of Sail |
6 kts TWS |
10 kts TWS |
15 kts TWS |
20 kts TWS |
| Close-hauled40–50° |
2.5 |
3.2 |
3.6 |
3.7 |
| Close Reach60° |
3.1 |
3.9 |
4.3 |
4.5 |
| Beam Reach90° |
3.8 |
4.8 |
5.3 |
5.5 |
| Broad Reach120–135° |
3.5 |
4.4 |
4.9 |
5.1 |
| Run150–180° |
2.8 |
3.5 |
3.9 |
4.1 |
These are simplified estimates based on hull speed (7.0 kts),
SA/D (13.7), and empirical efficiency curves — not instrument-measured
polars. Real-world speed varies with sea state, bottom condition, sail trim, and current.
Speeds in gold approach hull speed;
bold gold means near or at hull speed.
Wind Range & Comfort Envelope
Estimated wind ranges for comfortable sailing on the Block Island 40 — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–8 kts
8–20 kts
20–28 kts
28+ kts
Ghosting
0–8 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
8–20 kts
Comfortable under full sail. Best speed-to-comfort ratio.
Time to Reef
20–28 kts
Time to shorten sail. Reef the main, swap to a working jib.
Heavy Weather
28+ kts
Storm conditions. Storm jib or bare poles. Seek shelter if coastal.
How It Compares
Side-by-side with the boats most often cross-shopped against the Block Island 40.
|
Block Island 40 |
Bermuda 40 3 Hinckley |
Cartwright 40 |
Dickerson 40 |
Nevins 40 |
Newporter |
| Dimensions |
| LOA |
40.0 |
40.0 |
40.0 |
40.0 |
40.0 |
40.0 |
| LWL |
27.5 |
28.8 |
30.7 |
30.4 |
27.5 |
30.4 |
| Beam |
11.8 |
11.8 |
11.3 |
12.0 |
11.3 |
13.0 |
| Displacement |
21 |
20 |
23 |
18 |
22 |
24 |
| Ballast |
5 |
6 |
10 |
5 |
5 |
4 |
| Sail Area |
650 |
681 |
789 |
600 |
739 |
683 |
| Performance |
| PHRF |
— |
— |
153 |
197 |
177 |
209 |
| SA/Disp |
13.7 |
14.8 |
15.5 |
14.0 |
15.1 |
13.2 |
| Bal/Disp |
23.8 |
32.5 |
44.7 |
31.1 |
— |
— |
| Comfort |
39.0 |
36.1 |
43.2 |
30.5 |
43.3 |
36.6 |
| Capsize |
1.71 |
1.73 |
1.57 |
1.83 |
1.61 |
1.81 |
| Hull Speed |
7.0 |
7.2 |
7.4 |
7.4 |
7.0 |
7.4 |