F 31 Sport Cruiser Performance & PHRF

The F 31 Sport Cruiser is aggressively canvassed for its weight.

Hull Speed

The theoretical displacement-mode speed limit — determined by waterline length, not engine or sail power.

7.3 kts

A displacement hull pushes a bow wave whose speed is limited by the waterline length. With a waterline of 30.0′, the F 31 Sport Cruiser tops out around 7.3 knots in displacement mode — after that, the bow wave outruns the hull and resistance climbs steeply.

1.34 × √30.0′ LWL = 7.3 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

40.7

Performance-oriented — carries a lot of canvas for its weight.

Displacement / Length

Ultralight — responsive and fast, but carries less stores.

Hull Speed

7.3kts

PHRF Fleet Position

Where the F 31 Sport Cruiser sits on the PHRF handicap spectrum — lower numbers mean faster boats.

Racer 0–90

Cruiser/Racer 90–150

Cruiser 150–210

Noelex 30 119s/nm

Dehler 31 162s/nm

Catalina 309 167s/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°	3.4	4.3	4.9	5.1
Close Reach60°	4.2	5.3	5.9	6.1
Beam Reach90°	5.1	6.4	7.2	7.8
Broad Reach120–135°	4.7	6.0	6.7	7.2
Run150–180°	3.8	4.8	5.3	5.6

These are simplified estimates based on hull speed (7.3 kts), SA/D (40.7), 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 F 31 Sport Cruiser — based on sail area, ballast, and displacement characteristics.

Ghost

Sweet Spot

Reef

Heavy

0–5 kts 5–16 kts 16–24 kts 24+ kts

Ghosting

0–5 kts

Light air, motor-sailing likely. Need patience and a light genoa.

Sweet Spot

5–16 kts

Comfortable under full sail. Best speed-to-comfort ratio.

Time to Reef

16–24 kts

Time to shorten sail. Reef the main, swap to a working jib.

Heavy Weather

24+ 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 F 31 Sport Cruiser.

	F 31 Sport Cruiser	Catalina 309	Dehler 31	F 9A	Farr 30 Mumm 30	Noelex 30
Dimensions
LOA	30.8	32.8	30.8	30.8	30.9	30.9
LWL	30.0	26.5	24.3	30.0	27.6	26.8
Beam	22.4	11.5	10.2	22.4	10.1	9.4
Displacement	3	9,800	7	3	4	4
Ballast	—	4,000	2	—	1	1
Sail Area	599	452	443	—	504	410
Performance
PHRF	—	167	162	—	—	119
SA/Disp	40.7	16.4	19.3	—	29.4	25.6
Bal/Disp	—	40.8	40.6	—	43.8	31.4
Comfort	—	20.5	18.9	—	11.3	11.5
Capsize	—	2.15	2.12	—	2.44	2.34
Hull Speed	—	6.9	6.6	—	7.0	6.9