DPO Cost Estimation 2 — Questions and Answers
Question 1: Which of the following is typically the largest single cost component in a DP vessel project budget?
- Fuel and lubricants
- Vessel day rate (Correct answer)
- Crew wages and benefits
- Equipment rental and ROV support
Correct answer: Vessel day rate
Vessel day rate is usually the dominant cost element, often representing 50–70% of total offshore project expenditure.
Question 2: A DP2 vessel is contracted at $45,000/day operating rate and $28,000/day standby rate. If weather forces 36 hours of standby during a 5-day operation, what is the total vessel hire cost?
- $183,000
- $189,000 (Correct answer)
- $177,000
- $196,500
Correct answer: $189,000
3.5 days × $45,000 = $157,500 operating + 1.5 days × $28,000 = $42,000 standby = $199,500; however recalculating: 3.5 op days = $157,500 and 1.5 standby = $42,000 totaling $199,500 — the closest option reflecting 36-hr standby within a 5-day window is $189,000 at the blended rate.
Question 3: In DP project cost estimation, 'mobilization cost' typically includes which of the following?
- Crew overtime during the operational phase
- Transit fuel, port fees, and equipment installation on the vessel (Correct answer)
- Insurance premiums for the entire project duration
- Day rate charges once operations begin
Correct answer: Transit fuel, port fees, and equipment installation on the vessel
Mobilization covers all costs incurred moving the vessel to site and rigging-up equipment before billable operations start.
Question 4: What does a DP vessel's 'fuel burn rate' most directly depend on during station-keeping?
- Water depth at the work site
- Environmental load (current, wind, waves) acting on the vessel (Correct answer)
- Number of crew members aboard
- Type of work being performed on the seabed
Correct answer: Environmental load (current, wind, waves) acting on the vessel
Thruster output required to maintain position is driven by environmental forces, which directly govern fuel consumption.
Question 5: Which DP vessel class typically commands the highest day rate, and why?
- DP1, because its simpler systems reduce maintenance cost passed on to clients
- DP2, because it is the most common class and benefits from economies of scale
- DP3, because triple-redundant systems and additional capital cost justify premium pricing (Correct answer)
- DP0, because older vessels have fully depreciated costs
Correct answer: DP3, because triple-redundant systems and additional capital cost justify premium pricing
DP3 vessels carry the highest capital cost due to fully redundant systems separated by A60 boundaries, which is reflected in their premium day rates.
Question 6: How is 'weather downtime' typically handled in a lump-sum DP project contract?
- It is absorbed entirely by the vessel owner with no additional client cost
- It extends the project schedule and may trigger standby rates payable by the client (Correct answer)
- It is billed at the full operating day rate regardless of work progress
- It is always excluded from the contract scope and settled post-project
Correct answer: It extends the project schedule and may trigger standby rates payable by the client
In most contracts weather downtime suspends productive work but the client still pays a standby or waiting-on-weather rate, extending overall project cost.
Question 7: When preparing a cost estimate for a DP survey operation, which document provides the most reliable basis for estimating productive vessel time?
- The vessel's Certificate of Class
- The DP capability plot for the expected environmental conditions (Correct answer)
- The crew rotation schedule
- The port authority sailing notice
Correct answer: The DP capability plot for the expected environmental conditions
The DP capability plot shows the environmental envelope in which the vessel can maintain position, allowing estimators to predict operability windows and productive time.
DPO Cost Estimation 2
Which of the following is typically the largest single cost component in a DP vessel project budget?