greek armours

[Dan Howard]

"The weapon which the Papal injunctions had sought to ban was the composite crossbow of wood and horn...
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There were lighter variants of the steel crossbow than the ones Guilmartin seems obsessed with. Considering that his focus is on naval warfare and not the battlefield, this is understandable though. But you should not take his description of these very heavy crossbows and assume that they functioned the same as those intended for battlefield use.

The crossbow was first banned by the Second Lateran council in 1139. Much earlier than the 14th century implied above. The weapon at the time consisted of a simple wooden span - not the composite one of the 13th-14th century. Plate armour was not worn at all when crossbows were first banned.

Guilmartin also seems to be confusing the windlass with the cranequin. The windlass was used on lighter steel crossbows and only took around 12 seconds to load. This is hardly "a great deal of time". The cranequin was used on the heavier crossbows that Guilmartin discusses and required about 35 seconds to load.

Another thing you seem to be ignoring is the improvements to the trigger design in the 15th century that improved accuracy, and the addition of an adjustable wooden backsight for aiming. If these weapons were so inaccurate why bother with aiming devices?

If you want a decent source on crossbows then read Payne-Gallwey's "The Crossbow". It is considered the definitive work on this subject and covers all crossbows, not just those that might be relevant to naval combat.