Isotope
Fiberglass Unlimited · designed by Frank Meldau · 1962
twin centerboardscatamaranUnited States
The Isotope is a 16-foot catamaran sailboat designed by Frank Meldau and built by Fiberglass Unlimited, first launched in 1962.
General
| Builder | Fiberglass Unlimited |
|---|---|
| Designer | Frank Meldau |
| Years built | 1962 |
| Hull type | twin centerboards |
| Rig type | catamaran |
| Construction | fiberglass |
| Origin | United States |
Dimensions
| LOA | 16.00 ft4.88 m |
|---|---|
| LWL | —— |
| Beam | 7.50 ft2.29 m |
| Draft (max) | 2.50 ft0.76 m |
| Displacement | 275 lb125 kg |
| Ballast | —— |
| Sail Area | 185 ft²17.2 m² |
Design ratios
Computed from the specs above using the standard formulas. Try the sailboat calculators with your own numbers.
SA / Displacement 70.00 Performance / racer — powered up
Capsize Screening 4.61 Better suited to coastal use (> 2.0)
How these numbers are calculated
- SA / Displacement
SA ÷ (Disp ÷ 64)^(2/3)— Power-to-weight. < 16 under-canvassed, 16–20 cruiser, > 20 racer.- Ballast / Displacement
Ballast ÷ Disp × 100— Stability/stiffness. Higher carries sail better.- Displacement / Length
Disp(lt) ÷ (0.01 · LWL)³— < 100 ultralight, 100–200 light, 200–300 moderate, > 300 heavy.- Comfort Ratio (Brewer)
Disp ÷ (0.65 · (0.7·LWL + 0.3·LOA) · Beam^1.33)— Motion in a seaway. Higher = more comfortable offshore.- Capsize Screening
Beam ÷ (Disp ÷ 64)^(1/3)— ≤ 2.0 favored for offshore; > 2.0 better for coastal use.- Hull Speed
1.34 · √LWL— Theoretical max displacement speed in knots.
Estimated price
$6,500 typical range $5,000 – $8,000
⚠ Rough estimate only — not market data. Derived from a simple model based on length and hull age; actual asking prices vary widely with condition, equipment, engine hours and location.
