Wrought iron anchors recovered from archaeological sites invariably show signs of considerable corrosion loss. This affects cross-sectional dimensions and in turn particularly the bending and shear strength of anchor arms and lower part of the shanks and also the original potential holding power of the anchor. To assist in estimating such loss of strength, herein the amount of corrosion loss for long-term exposures is used to obtain estimates of the critical original cross-sectional sizes for some 40 calcareous encrusted anchors recovered from archaeological sites. From these, the ratio of critical size to arm span of anchors is estimated. This ratio is then considered as an indicator of the historical development of anchors, from the early Roman period to the mid-1800s. The results are compared to the (narrow) range of the proportions of Old Plan Admiralty Long-Shank anchors as derived from the dimensions for 6 sheet anchors published in the literature. The results permit estimation of the original critical dimensions of iron anchors after they have corroded for a specific period of time under calcareous conditions and known average temperature.

从考古遗址中回收的锻铁锚总是显示出相当大的腐蚀损失的迹象。这会影响横截面尺寸，进而影响锚臂和锚杆下部的弯曲和剪切强度，以及锚的原始潜在保持力。为了帮助估计这种强度损失，本文使用长期暴露的腐蚀损失量来估计从考古遗址回收的大约 40 个钙质包覆锚的临界原始横截面尺寸。根据这些，估计锚的临界尺寸与臂展的比率。这个比率随后被认为是锚的历史发展的指标，从罗马时期早期到 1800 年代中期。结果与从文献中公布的 6 个板锚的尺寸得出的 Old Plan Admiralty Long-Shank 锚的比例（窄）范围进行了比较。结果允许估计铁锚在钙质条件和已知平均温度下腐蚀特定时间后的原始临界尺寸。