Real-world tender TCO for a 70 m mothership

Owner here. Planning a tender upgrade and looking for real-world costs and lessons learned on 8–12 m tenders. Not brand shopping, just trying to avoid rookie mistakes.

Constraints

• Mothership in the 70 m range, Med based
• Garage door about 6.3 W × 3.1 H m, measured clear opening
• Internal stow height 2.0 m clear
• Crane SWL 2.5 t
• Primary use: guest shuttle 70%, beach landings 20%, light utility 10%
• Fuel logistics favour diesel or outboards
• Target 38–42 kn light, delivery in 2025–2026
  

What I’d value most

• Annual spend years 1–3 as a percent of purchase price
• Fuel burn at 25–30 kn with 4–8 guests
• Tube or collar life you actually see on RIBs
• Jet vs outboard maintenance cycles and downtime
• Common refit items in years 3–5 and what they cost
• Lead times since 2023 and causes of delay
• Resale after 3–5 seasons, percent of original recovered

I will share my numbers once I lock a spec. Thanks in advance.