Steel Developments
South London marine propeller specialist, founded in 1958, that repairs, sells and race-prepares boat propellers and in 2026 ran laser powder bed fusion (DMLS) printed stainless steel race propellers at the UIM F2 World Championship.
- CEO / Founder
- David John (Dave) Harwood
- Stage
- Active
Technology & Products
Key Products
Propeller blade repair and rebush service; lab finish and race preparation; outboard propeller ranges (Series A-E); Volvo, Enfield, BMW and Mercruiser outdrive propellers; Mercury OEM propellers; reconditioned second-hand propellers; Thundercat/Zapcat racing propellers; bronze, ski-boat and sailing propellers; accessories. It is also developing five-bladed DMLS stainless steel race propellers.
Technological Advantage
Large in-house dataset of competitive race propellers on the OptiMax 200XS engine. Experience developing hardened 17-4 stainless steel race props. The DMLS propeller programme follows two years of FDM blade-profile modelling and material property studies, and next iterations use a first-principles model varying pitch, aspect ratio and diameter for the APX250 engine.
Differentiation
Value Proposition
Propeller repair, alteration, lab finishing and race preparation for propellers up to six feet in diameter, alongside stock replacement propellers for outboards and outdrives. The company is now also developing metal 3D-printed race propellers for powerboat racing.
How They Differentiate
Specialist race-prop tuning for British and international UIM F2 teams, plus a claimed first for metal 3D-printed propellers run at a world championship.
Market & Competition
Target Customers
Recreational boat owners, marine trade customers, superyacht and small commercial vessel operators, and powerboat racing teams (circuit, offshore, UIM F2, Thundercat/Zapcat).
Industry Verticals
Marine; recreational boating; powerboat racing; commercial and superyacht vessels
Competitors
Mercury Racing (propellers); Hydromotive Engineering; other UK propeller repair specialists
Growth & Milestones
Growth Metrics
Trading since 1958; most stock items shipped within 24-48 hours; services most British UIM F2 teams at race weekends.
Major Milestones
1958: Company founded by the Harwood family. 2008: David Harwood appointed director. 2024: 3D-printed propeller concept initiated with Caleb Jelf. Sept 2026: Two DMLS stainless steel five-bladed propellers completed more than 60 laps in free practice at the UIM F2 Peso da Régua round, within 0.5 s of the session's fastest propeller.
Notable Customers
UIM F2 race teams including those of Owen Jelf and Ian Blacker; 51 Racing team