[CODOG]

Originally Posted by C4ENG

Also which is more heavier of the same build, steel or composite? I have been told a glass haul wieghs more... besides those graphite composite go fast yacht situations..

As a generalisation, composite is lighter than steel in most cases. The comparison between like for like builds is easier, as you can compare weights square metre for square meter. It gets a little more complicated when you take into account the various properties of a material such as impact strength, the need for filler / paint, corrosion, deflection, maximum panel spans etc etc etc. A composite cored bulkhead for example can be a fraction of the weight of an equivalent plate steel bulkhead yet offer far more rigidity with far less stiffening. A composite single-skin hull shell on the other hand, wont boast as large a weight saving against a steel plate shell due to the layup needed for optimum stiffness and minimal panel deflection.
A closer weight comparison can be made between aluminium alloy and composite construction. Like for like builds are very close in all up weight.