Free marine piping and systems symbols for AutoCAD (DWG): bilge, ballast, fuel oil, sea water, fire main

About the symbols

Ship piping diagrams follow the standards of the yard, the classification society and the flag state, and each uses its own legend and system codes. These symbols follow common shipbuilding practice and are not a copy of any one of them; check the legend that applies to your project.

The symbols are our own drawings, not copies of any standard or manufacturer's catalogue, and the library is not certified. Take exact dimensions and ratings from the equipment data sheets.

Frequently asked questions

Which symbols are in the library?

Thirty piping system lines, valves, fittings, strainers and filters, pumps and compressors, tanks, heaters and treatment plants, gauges and sensors, hull, deck and overboard fittings, fire-fighting systems, and lines and drawing marks. The list above shows every symbol.

Can I use these symbols for a class-approved piping diagram?

Use them as a starting point. Classification societies and flag states expect their own legend and system codes on submitted drawings, so check the legend of your project and adapt the symbols or codes where it differs.

Can I use the symbols in commercial projects?

Yes. They are free to use and modify in your own projects, including commercial ones. They are provided as is, without warranty.

Where are the ship arrangement blocks and the fire control symbols?

Ship types, deck equipment, cabins and engine room machinery at real size are in the ship general arrangement library. Process and instrument symbols are in the P&ID and instrumentation libraries; the fire-fighting symbols here are the piping-side items only.

Can I change a symbol or add attributes?

Yes. Open the DWG, edit a block with BEDIT to change it or add attributes, and save. To update drawings that already contain the block, run ATTSYNC or replace the block. Make a backup first: attribute values can be lost if ATTSYNC is used carelessly.

Where do I find a ready-made set of these symbols for AutoCAD?

AutoCAD itself ships only a small set of sample blocks, so a full symbol set has to come from a library. Download the ZIP on this page and open the DWG: every symbol is a block. Insert one with INSERT (Blocks palette, Libraries tab, then pick the DWG) or drag it from DesignCenter (ADCENTER). You can also download a single symbol on its own.