Monohull · 12 documented fitments
Propeller upgrade for the Nauticat 331 — what fits, what changes.
Drawn from 12 documented Nauticat 331 fitments: the common setup is an Autoprop H6 behind the Yanmar 4JH3TE. Typical result: 300–400 fewer RPM at cruise and up to 20% fuel saved over fixed pitch.
The fitment card
Documented engine variants & what they wear
Aggregated from 12 real installations — not a size chart, a service record.
| Engine | Power / max RPM | Drive | Typical ratio | Documented propeller | Rotation | Records |
|---|---|---|---|---|---|---|
| Yanmar 4JH3TE | 75 hp / 3800 | Shaft | 2.63:1 | Autoprop H6 | Left-hand | 4 |
| Yanmar 4JH-DTE | 88 hp / 3600 | Shaft | 2.62:1 | Autoprop H6 | Right-hand | 3 |
| Yanmar 4JH3 TE | 75 hp / 3800 | Shaft | 2.63:1 | Autoprop H6 | Right-hand | 1 |
| Yanmar 4JH4TE | 75 hp / 3200 | Shaft | 2.63:1 | Autoprop H6 | Right-hand | 1 |
| Yanmar 4JH3-TBE | 75 hp / 3800 | Shaft | 2.63:1 | Autoprop H6 | Left-hand | 1 |
| Yanmar 4JH3-TE | 75 hp / 3800 | Shaft | 2.63:1 | Autoprop H6 | Left-hand | 1 |
| Yanmar 4JH4-TE | 75 hp | Shaft | 2.63:1 | Autoprop H6 | Right-hand | 1 |
Indicative only — gearboxes and apertures vary between years and repowers, which is why every supplied propeller is verified against your boat first. Data current as of 2026.
Your numbers
What the change feels like on a Nauticat 331
Indicative curves for this size of boat — drag the cruise line. The independent-test pattern: the same six knots on several hundred fewer RPM, with the fuel flow following.
Worth knowing
Considerations for the Nauticat 331
- 7 engine variants are documented for this model — repowers included. Sizing follows your engine and ratio, not the year in the brochure.
- Tip clearance rules the maximum diameter — roughly 10–15% of prop diameter to the hull. The Builder asks; we verify before supply.
Nauticat 331 propeller questions
What size propeller does a Nauticat 331 take?
Documented Nauticat 331 installations most commonly run an Autoprop H6, matched to the Yanmar 4JH3TE on a shaft drive. Exact size depends on your engine, gearbox ratio and aperture — every recommendation is verified by an engineer before supply.
How much fuel would a Nauticat 331 save with an Autoprop?
Typical savings over a fixed-pitch propeller are up to 20% at cruise (documented band 15–30%, honestly less if you already run a folding or feathering prop). Put your engine hours and diesel price into the fuel calculator for your own numbers — then the Builder for a verified recommendation.
My Nauticat 331 has a different engine than shown — does the data still help?
Yes. Repowers are common and the database usually holds several engine variants per model. The Builder starts from your actual engine and gearbox; the model records confirm diameters and clearances that are known to work on this hull.
Get the verified recommendation for your Nauticat 331
The Builder pre-fills from these 12 documented fitments — confirm your engine and gearbox, and an engineer replies within one business day.