A hull maintenance workshop that sands, paints and blows down two or three boats at once needs somewhere around 1.5 to 2 m³/min of dry air. A K 150 4-in-1 (2.2 m³/min at 8 bar) installed in a plant room covers this with a reserve. If boats move around the hard standing, an M 220 mobile unit (2.0 m³/min at 12.5 bar) can be wheeled to the foot of each hull. A single-station workshop can make do with a K 75.
Our page on the compressor for boatyards covers every use in a yard, blasting included. Here we size the hull maintenance workshop.
The stations in a day of hull work
Consumption for guidance only, at about 6 bar. Each tool's manual is the reference.
| Tool | Consumption | Use |
|---|---|---|
| Orbital sander | 350 L/min | Continuous |
| Rotary sander or polisher | 400 L/min | Continuous |
| Paint or varnish spray gun | 350 L/min | Continuous while spraying |
| Grinder | 450 L/min | In spells |
| 1/2" impact wrench (propeller, anodes) | 300 L/min | Short bursts |
| Blow gun | 150 L/min | Short bursts |
The calculation, step by step
The rule in our configurator: a tool that runs continuously counts at 100%. A tool used in short bursts counts at 50%, because the receiver absorbs the peaks. Then add a 25% margin.
Example: three boats on the hard.
- Continuous tools: two orbital sanders, 2 × 350 = 700 L/min, and one spray gun, 350 L/min. Subtotal: 1,050 L/min.
- Short-burst tools: one impact wrench, 300 L/min, and one blow gun, 150 L/min. Counted at 50%: 225 L/min.
- Total: 1,275 L/min.
- With a 25% margin: about 1,600 L/min, or 1.6 m³/min.
The K 110 delivers 1.7 m³/min at 8 bar: tight, with no room for another station. The K 150, 2.2 m³/min at 8 bar, leaves room for a fourth sander. Our flow and pressure converter switches between L/min and m³/min.
Fixed or mobile compressor?
Covered workshop with an air network: the K 150
Compressor, 340 L receiver, refrigerated dryer and filtration sit on a single frame. The air reaches the outlets dry. Run a network to the boat bays, with one outlet per station.
Open hard standing, boats that move: the M 220
The M 220 is an electric screw compressor on a twin receiver of 180 L in total, mounted on wheels. You bring it to the boat instead of running long hoses. It needs a 380 V three-phase socket on the hard, and a dryer at the outlet for painting stations.
Small marina workshop, one station: the K 75
One sander and one blow gun: 350 + 75 = 425 L/min, about 530 L/min with the margin. The K 75 delivers 1.1 m³/min at 8 bar with a 420 L receiver. For a single station that moves around, the M 75 delivers 1.0 m³/min at 10 bar.
The spring peak
When every relaunch falls in the same few weeks, compressor rental from 5.5 to 132 kW adds extra capacity for the season. Ask us when you request a quote.
Pitfalls specific to hull work
- Hose length. Thirty metres of narrow hose around a hull drops the pressure at the sander. Bring outlets closer to the boats and use a suitable diameter. See a leak-free compressed air network.
- Damp air. Sea air carries a lot of water. For paint and varnish, add fine filters at the station and define the air class with our technicians.
- Sanding dust. Place the compressor well away from the sanding area, with a clean air intake. Otherwise the intake filter clogs within days.
- Condensate. It contains oil. Never discharge it into the harbour: collect it and have it treated. See condensate draining.
Add up your stations in the configurator or send us your tool list with a quote request.
For your trade: Compressor for boatyards and marinas.