Launch-type boiler
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![End-on view of the furnace, showing the small steam space above](/Images/godic/202501/16/Skansen_w_Chabówce_-maszyna_081448.JPG")
![Early semi-portable engine, 1860s, with enlarged furnace](/Images/godic/202501/16/DMM_2562_Dampflokomobile1448.jpg")
![Locomotive Effie on Sir Arthur Heywood's Duffield Bank Railway](/Images/godic/202501/16/Effie_Duffield_Bank_Railway1448.jpg")
A launch-type, gunboat or horizontal multitubular boiler is a form of small steam boiler. It consists of a cylindrical horizontal shell with a cylindrical furnace and fire-tubes within this.
Their name derives from the boiler's popular use at one time for small steam yachts and launches. They have also been used in some early Naval torpedo boat destroyers.