The Sigma 36 Thomas is well-powered with enough sail area to move in light air, with acceptable motion comfort for coastal passages.
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 28.8′, the Sigma 36 Thomas tops out around 7.2 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.
1.34 × √28.8′ LWL = 7.2 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
18.2
Powerful cruiser/racer — quick in light air, reef early when it pipes up.
Displacement / Length
232
Moderate — a good balance of speed and load-carrying ability.
Comfort Ratio
23.9
Acceptable coastal comfort — fine for weekends, notice the chop offshore.
Capsize Screening
1.99
Below the 2.0 offshore threshold — acceptable for ocean passages.
Pounds/Inch Immersion
1lbs
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
23.9
Acceptable coastal comfort — fine for weekends, notice the chop offshore.
Under 20 — Snappy, racing motion
20–30 — Acceptable coastal
30–40 — Good offshore comfort
Over 40 — Very comfortable offshore
Capsize Screening Formula
1.99
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 Sigma 36 Thomas sits on the PHRF handicap spectrum — lower numbers mean faster boats.
Racer 0–90
Cruiser/Racer 90–150
Cruiser 150–210
Cs 36 Merlin
126s/nm
C&C 36
132s/nm
Sabre 36
144s/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° |
3.0 |
3.7 |
4.2 |
4.4 |
| Close Reach60° |
3.6 |
4.5 |
5.0 |
5.3 |
| Beam Reach90° |
4.4 |
5.5 |
6.2 |
6.5 |
| Broad Reach120–135° |
4.1 |
5.1 |
5.7 |
6.0 |
| Run150–180° |
3.2 |
4.1 |
4.6 |
4.8 |
These are simplified estimates based on hull speed (7.2 kts),
SA/D (18.2), 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 Sigma 36 Thomas — based on sail area, ballast, and displacement characteristics.
Ghost
Sweet Spot
Reef
Heavy
0–6 kts
6–18 kts
18–26 kts
26+ kts
Ghosting
0–6 kts
Light air, motor-sailing likely. Need patience and a light genoa.
Sweet Spot
6–18 kts
Comfortable under full sail. Best speed-to-comfort ratio.
Time to Reef
18–26 kts
Time to shorten sail. Reef the main, swap to a working jib.
Heavy Weather
26+ 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 Sigma 36 Thomas.
|
Sigma 36 Thomas |
C&C 36 |
Cs 36 Merlin |
S2 110 C |
Sabre 36 |
Sigma 362 |
| Dimensions |
| LOA |
36.0 |
36.0 |
36.0 |
36.0 |
36.0 |
36.0 |
| LWL |
28.8 |
— |
29.2 |
28.3 |
29.3 |
28.0 |
| Beam |
11.5 |
— |
11.5 |
11.9 |
11.3 |
11.5 |
| Displacement |
12 |
— |
13 |
16 |
13 |
12 |
| Ballast |
— |
— |
5 |
6 |
5 |
5 |
| Sail Area |
605 |
— |
608 |
625 |
610 |
— |
| Performance |
| PHRF |
— |
132 |
126 |
— |
144 |
— |
| SA/Disp |
18.2 |
— |
17.7 |
15.8 |
17.5 |
— |
| Bal/Disp |
— |
— |
43.0 |
— |
— |
41.6 |
| Comfort |
23.9 |
— |
24.9 |
29.8 |
25.9 |
— |
| Capsize |
1.99 |
— |
1.96 |
1.90 |
1.91 |
— |
| Hull Speed |
7.2 |
— |
7.2 |
7.1 |
7.3 |
— |