Ferrocement

Ferrocement

This involves the construction of an armature, typically with water pipe/fabricated transverse frames, round bar longitudinal stringers, and then cladding mesh. Building this armature is a major commitment of relatively low skill labour. The completed armature is then plastered with cement, with a small cover (3 – 5 mm) over the mesh. The hull is then finished and fitted out.

Hull plastering with cement is typically done by experienced contract labour.

The cement plastering and outside painting normally give reasonable corrosion resistance.

This construction technique does not lend itself to a high degree of fairing and surface finish.

Ferrocement is not commonly applied in current practice. It is almost exclusively for the larger moored boats for cruising. It gives great opportunity for building hulls at relatively low dollar cost, particularly if the main hull construction labour is at low or zero cost. The method does carry the risk of poor hull shaping/fairing, and the risks associated with the main hull material generation being under the direct control of the boatbuilder. (The manufacture of the major alternative materials of steel, aluminium, plywood etc are under established factory control.)

Hartley Boat Plans is the major supplier of designs for ferrocement boats. It is claimed that there have been more ferrocement  boats built to Hartley designs than all other designers combined. See Ferroboats following.

The relatively high labour content, with low material cost have worked against this hull construction material for commercial construction. However these, the ability to build the hull in the open, and the ease of generating curved surfaces are attractive for the amateur builder.

 

A Warning

The relatively low cost of building a hull in ferrocement (particularly where much of the labour is unpaid) can encourage a builder to choose a substantially larger boat (because it is “affordable”) than originally intended. All too often it is not realised that the larger boat will call for more extensive and larger outfit and rig/propulsion. The costs of these depend upon the boat size, but not the hull construction material. Many a construction project has ground to a halt due to these unanticipated late project cost escalations. Hull, outfit and propulsion/rig each represent around 1/3  of the cost of a cruising or similar boat.

 

Ferroboats Website

This site is supported by Hartley and Brookes Associates, and is based on many years of first-hand experience of use, designing, surveying, building and repairing ferro-cement boats. It is devoted to the promotion of Ferroboats and is a base for all matters Ferro in the boating world.

It covers many areas, including both Hartley and Samson galleries, a forum and boats for sale. It also covers ferro sheathing of old wooden boats.

This site is a “must see” for anyone interested in this construction material.

 

 

 

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