Important limitation: I do not have live web browsing in this chat, so I cannot “click-check” that any product link works right now. I only included manufacturer/homepage or stable reference links I expect to persist, but you should verify each URL and request datasheets for confirmed bollard thrust at a stated power and RPM.
Comparison caveats: “Thrust” numbers can be measured differently (static/bollard in still water vs at-speed; freshwater vs seawater; duct/nozzle vs open prop; different prop diameters). A submersible mixer’s very high static thrust/kW often comes from very large disk area at very low jet velocity (excellent for near-static pushing), but it can be bulky/heavy and not optimized for forward-speed efficiency.
| Type | Lbs Thrust | Watts | lbs/kw | $ price | $/lbs-thrust | URL |
|---|---|---|---|---|---|---|
| RIM drive (outboard): Yamaha HARMO (rim motor integrated around prop) | 227 | 3700 | 61.4 | ~$3,500 (you-est.) | ~$15.4 | https://www.yamaha-motor.eu/ |
| Submersible mixer (slow-speed axial flow mixer; wastewater/industrial style) | 720 (example you quoted) | 3200 (example you quoted) | 225 | ~$12,000 (you-est.) | ~$16.7 | Example category/vendor (datasheets vary): https://www.xylem.com/ |
|
Ducted prop (Kort nozzle) + low-RPM electric motor (custom pod/strut build; not rim drive)
Best “thrust per kW” lever is big prop disk area at low RPM. If you truly can swing ~2.5 m props, a ducted/nozzle prop
can be very effective for static/low-speed pushing. Numbers below are engineering estimates (not vendor specs).
|
~900–1350 (est.) | 10,000 (example sizing) | ~90–135 (est.) | ~$6,000–$12,000 (est., DIY/parts) | ~$4.4–$13.3 (est.) |
Kort nozzle reference:
https://en.wikipedia.org/wiki/Kort_nozzle
Static thrust estimation background: https://en.wikipedia.org/wiki/Actuator_disk_theory |
|
Open prop + low-RPM electric motor (custom; not rim drive)
Typically a bit less static thrust than a good nozzle at the same diameter/power, but mechanically simpler and often less drag at speed.
Numbers below are engineering estimates.
|
~800–1240 (est.) | 10,000 (example sizing) | ~80–124 (est.) | ~$5,000–$11,000 (est., DIY/parts) | ~$4.0–$13.8 (est.) | Propeller basics: https://en.wikipedia.org/wiki/Marine_propeller |
|
Tunnel/bow thruster (ducted, transverse) — generally not ideal for continuous forward propulsion
Included only as a price/performance reference: these are mass-market and comparatively cheap, but they’re designed for
low-duty docking loads, and the geometry is not optimized for pushing a platform forward continuously.
|
~150–300 (typical range) | ~5,000–10,000 (typical range) | ~15–60 (typical range) | ~$1,500–$5,000 (typical range) | ~$5–$33 (typical range) | Example vendor category: https://www.sleipnergroup.com/ | https://www.vetus.com/ |
|
Commercial rim-driven thrusters (ship-grade; true rim motor around prop)
Reality check: larger rim drives do exist, but they are typically sold into commercial/military markets (RFQ pricing)
and often at much higher power levels than a few kW. Getting “Yamaha HARMO-like $/kW” at larger sizes is uncommon.
|
RFQ / datasheet | Typically 10 kW to MW-class (varies) | RFQ / depends on prop diameter & RPM | RFQ (often high) | RFQ |
Rim Drive Technology (company):
https://www.rimdrivetechnology.com/
SCHOTTEL (rim thruster category may be under products; verify): https://www.schottel.de/ Kongsberg (propulsion/thrusters; verify): https://www.kongsberg.com/ |