Fishing Vessel Stability & Modifications

Commercial fishing is one of the most dangerous occupations. While statistics vary from year to year, the numbers from 1996 remain typical - one hundred thirty six (136) U.S. fishing vessels were lost. Of this total, 45 were in some way "stability related", and nine of these vessels accounted for 19 lives lost. It is important to understand the term "stability related". At least 75% - 80% of "stability related" sinkings are caused by either overloading, or flooding through deteriorated systems or boundaries, non-tight closures, or other openings added for operational convenience. These events impair or invalidate the designed stability characteristics of an otherwise seaworthy vessel.

Obsolete stability guidance is another factor with the potential to increase stability-related risks. All vessels experience weight growth over time, and a good rule of thumb is to have a naval architect review stability every five years, or when vessel modifications are made. Undocumented changes are especially dangerous since the vessel crew may not be aware that the stability guidance is obsolete. Modifications affecting stability include any weight changes, watertight bulkhead alterations, tank boundary changes, fishing method changes, freeing port alterations, lifting gear changes, windage changes, ventilation terminal changes, bilge keel area changes, and repowering. While the risks are high, so can be the profits. The fisherman must weigh the risks of his occupation against the benefits. Many losses result from deferring maintenance of watertight & weathertight closures.