5.2.2. Maintenance Vessel and Cost
Multiple options for vessel type can be considered. For
minor maintenance, a monohull, catamaran or SWATH
type vessels are suitable. Monohulls provide relatively
high cruising speeds (approx. 25 knots) whereas catamaran
type vessels normally cruise at 20 knots and SWATH
vessels at 15 knots. SWATH vessel operational limits allow
for wave heights of up to 60% higher than that for
monohull vessels. However, since SWATH day rates are
unknown to us, we chose a monohull AHTS for this scenario.
For major maintenance operations, heavy lift vessels
might be required.
Based on an average AHTS vessel with a day rate of
€ 12,000, and fuel costs of € 4,500/day (based on a consumption
of 10 tons/day), and a cost of € 1,000 per day
for crew, the costs of 3 scenarios were calculated in Table
5.3.