Monohull · 7 documented fitments
Propeller upgrade for the Sadler 25 — what fits, what changes.
Drawn from 7 documented Sadler 25 fitments: the common setup is a Varifold 2-blade behind the Yanmar 1GM10. 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 7 real installations — not a size chart, a service record.
| Engine | Power / max RPM | Drive | Typical ratio | Documented propeller | Rotation | Records |
|---|---|---|---|---|---|---|
| Yanmar 1GM10 | 9 hp / 3600 | Shaft | 2.21:1 | Varifold 2-blade | Right-hand | 3 |
| Volvo Penta MD2010C | 9 hp / 3600 | Saildrive | 2.47:1 | Autoprop H20 | Left-hand | 1 |
| Beta Marine 10 | 9 hp / 3000 | Shaft | 2:1 | Varifold 2-blade | Right-hand | 1 |
| Bukh DV10 | 9 hp / 3000 | Shaft | 2.47:1 | Varifold 2-blade | Right-hand | 1 |
| Volvo Penta 2001 | 9 hp / 3200 | Shaft | 2.34:1 | Varifold 2-blade | Left-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 Sadler 25
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 Sadler 25
- Shaft and saildrive variants exist across model years — the APS saildrive series covers the latter; check which yours is before comparing quotes.
- 5 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.
Sadler 25 propeller questions
What size propeller does a Sadler 25 take?
Documented Sadler 25 installations most commonly run a Varifold 2-blade, matched to the Yanmar 1GM10 on a shaft drive. Exact size depends on your engine, gearbox ratio and aperture — every recommendation is verified by an engineer before supply.
Will an Autoprop fit my saildrive Sadler 25?
Yes — saildrive installations are documented for this model, using the APS saildrive variants with the appropriate spline and anodes. Tell us your drive model (e.g. Volvo 130S, Yanmar SD25) and we confirm the fitment.
How much fuel would a Sadler 25 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 Sadler 25 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 Sadler 25
The Builder pre-fills from these 7 documented fitments — confirm your engine and gearbox, and an engineer replies within one business day.