Tender Specification Guide

A specification document is the bridge between a brief and a built boat. A usable tender spec covers eight areas, from mothership role and dry-weight target through to sea-trial pass criteria and handover documentation.

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A specification document is the bridge between a brief and a built boat. Done well, it eliminates ambiguity at every contract milestone and gives both yard and owner a single reference for acceptance. Done poorly, it surfaces as change orders, schedule slip, and a delivered boat that nobody is happy with. This page covers the structure of a usable tender spec.

What sits in the spec

A good tender spec covers eight areas. Each section runs to a page or two on a custom build, less on semi-custom.

1. Mothership and operational role

  • Mothership name, length, and beam.
  • Garage dimensions: length, beam, headroom, deck loading.
  • Davit class and lifting capacity.
  • Cruising programme and primary geography.
  • Role mix: guest transfer, beach landing, water-toy support, chase, SOLAS, crew shuttle. Rank by frequency.

2. Hull and dimensions

  • LOA, beam, draft (engines down and up).
  • Dry weight (target, maximum).
  • Hull material (GRP, GRP-Kevlar, carbon, aluminium).
  • Deck material (GRP, teak, synthetic teak, composite).
  • Hull form (deep-V deadrise, twin-stepped, planing, semi-displacement).
  • Owner colour-match specification with the mothership's livery code.

3. Drivetrain and performance

  • Engine make, model, and count.
  • Drive type (jet, sterndrive, outboard, IPS, shaft).
  • Target top speed and cruise speed in named conditions (e.g. "Force 3, half load").
  • Fuel capacity and fuel type.
  • Range at cruise.

4. Capacity and certification

  • Guest capacity (CE Cat A/B/C or coded equivalent).
  • Crew capacity.
  • Classification (SOLAS, MCA, RCD, CE Cat).
  • Flag-state coding requirements.

5. Layout

  • Cockpit configuration (open, U-sofa, bar, cabin module).
  • Helm layout: number of screens, manufacturer, position.
  • Stowage: locker dimensions, fender storage, refrigeration.
  • Bow geometry: cleats, anchor, locker.
  • Swim platform geometry, boarding ladder, watermaker showerhead.

6. Equipment fit

  • Navigation and electronics package.
  • Audio system specification.
  • Refrigeration capacity.
  • Watermaker capacity (where fitted).
  • Toilet (Vacuflush, manual head, none).
  • Davits, lifting strop, certification.

7. Build-quality clauses

  • Vibration limits at named RPM.
  • Noise limits at named RPM.
  • Cosmetic acceptance criteria for paint, gelcoat, joinery.
  • Warranty terms.

8. Delivery and acceptance

  • Sea-trial conditions and pass/fail criteria.
  • Punch-list resolution timeline.
  • Handover documentation: O&M manuals, certificates, spares.
  • Delivery location.

What's typically over- or under-specified

Common over-specs we see: top speed in unrealistic conditions, fuel range that ignores typical loading, audio and entertainment systems that double the wiring complexity for limited owner benefit.

Common under-specs: dry-weight target (drives lifting compatibility), spares package, vibration and noise limits, and the cosmetic acceptance criteria for joinery and paint.

Who writes it

For semi-custom and production builds, the yard provides a base spec sheet that the owner annotates. For custom builds, we draft the spec in collaboration with the owner's project manager and a naval architect on the hull and lifting sections, then tender it to the shortlisted yards as the basis for fixed-price quotation.

See also

What does a tender specification actually need to cover?
Eight areas. Mothership and operational role; hull and dimensions; drivetrain and performance; capacity and certification; layout; equipment fit; build-quality clauses; and delivery and acceptance. On a custom build each section runs to a page or two, less on semi-custom. That structure eliminates ambiguity at every contract milestone and gives both yard and owner a single reference for acceptance. Where it is thin, the gaps surface later as change orders, schedule slip, and a delivered boat that nobody is happy with.
What do owners most often get wrong when writing a spec?
The common over-specs are top speed in unrealistic conditions, fuel range that ignores typical loading, and audio and entertainment systems that double the wiring complexity for limited owner benefit. The common under-specs are the dry-weight target, which drives lifting compatibility, the spares package, vibration and noise limits at named RPM, and the cosmetic acceptance criteria for joinery and paint. The under-specified items are the ones that cause trouble at handover, because there is no agreed standard to measure the delivered boat against.
Who should draft the document - the yard or the owner's team?
It depends on the build route. For semi-custom and production builds, the yard provides a base spec sheet that the owner annotates. For custom builds, we draft the spec in collaboration with the owner's project manager and a naval architect on the hull and lifting sections, then tender it to the shortlisted yards as the basis for fixed-price quotation. That sequencing matters: a single spec issued to several yards is what makes quotations comparable.
How should performance figures be written so they mean something?
Tie them to named conditions. Target top speed and cruise speed should be stated in conditions such as "Force 3, half load", with fuel capacity, fuel type and range at cruise alongside them. Speed claimed in unrealistic conditions and range that ignores typical loading are two of the over-specs we see most. The same discipline applies to build quality: vibration and noise limits belong in the spec at named RPM, not as a general expectation.
What needs to be agreed about delivery before the boat is built?
Four things: sea-trial conditions and pass/fail criteria, the punch-list resolution timeline, handover documentation, and delivery location. Handover documentation covers O&M manuals, certificates and spares. Certification sits in its own section of the spec and should record guest capacity against CE Cat A/B/C or the coded equivalent, crew capacity, classification under SOLAS, MCA, RCD or CE Cat, and flag-state coding requirements. Agreeing acceptance criteria in writing is what makes the trial a test rather than a negotiation.

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