What a Marine Survey Actually Checks, System by System

The three common survey types behave differently. The buyer should know which one is on the schedule.

• Pre-purchase (condition and value) survey. The longest and most comprehensive of the three. Covers the hull, structure, every onboard system, and includes a haul-out and a sea trial. Produces a written report with a list of deficiencies coded by severity, recommendations, and an assigned fair market value. The standard for any boat purchase in Connecticut.
• Insurance survey. Shorter, narrower. Confirms the boat is an acceptable underwriting risk and assigns an insured value. Focuses on safety equipment, machinery condition, hull integrity, and obvious code violations against ABYC, NFPA, and USCG. Most underwriters accept an in-date pre-purchase survey for the binder, especially in the first three years.
• Damage survey. Triggered by a casualty — grounding, lightning strike, fire, sinking. Documents the damage, recommends a repair scope, and supports the insurance claim. Often the surveyor returns to inspect the completed work before the underwriter pays out.

The rest of this article covers the pre-purchase survey because it is the most thorough and the one with the most at stake. Insurance and damage surveys are subsets of the same discipline, narrower in scope.

Marine surveying is not a regulated profession in the United States the way home inspection is in Connecticut. Anyone can call themselves a marine surveyor. The two accreditation bodies that actually carry weight with banks, underwriters, and the legal system are:

• NAMS — National Association of Marine Surveyors. Accredited Marine Surveyor (AMS) designation. Requires experience, examination, ongoing continuing education, and adherence to a published code of ethics.
• SAMS — Society of Accredited Marine Surveyors. Accredited Marine Surveyor (AMS) designation, same examination standard, broader membership, comparable industry recognition. SAMS publishes its own Survey Practice Recommendations.

Both are widely accepted by Connecticut lenders and marine insurance carriers. The honest practitioner mix in CT runs heavily SAMS-leaning on the powerboat side and roughly even on the cruising-sailboat side. The single most useful screening question is “Are you NAMS or SAMS accredited?” — if the answer is neither, the report will not satisfy most insurers and many banks. The full screening conversation lives in the surveyor selection guide.

The surveyor should also be independent of the seller, the broker, the marina, and the bank. A surveyor with a financial relationship to any party in the transaction is conflicted. The report will not hold up if the conflict becomes public.

The hull and the deck are the structural backbone of the boat. The surveyor's read of them decides almost every other line in the report.

Inside the hull, the surveyor inspects:

• The bilge and the sump for signs of past flooding, oil contamination, fuel contamination, fresh-water leakage, and the corrosion patterns that come with each.
• The bulkheads where they tie into the hull and the deck — for tabbing failure, water staining, and the spongy-feel pattern of delamination.
• The stringers and floors for fractures and water saturation, particularly on older wood-cored stringer construction.
• The chainplate roots on a sailboat and the engine mounts on a powerboat for crevice corrosion and stress cracking. Chainplate failure is the most common rigging-survey deficiency in the CT fleet.
• The keel-to-hull joint on a fin-keeled sailboat for smile cracks, working, and elevated moisture on either side of the seam.

Outside the hull, on the hard during the haul, the surveyor walks the entire bottom looking for:

• Blisters, osmotic patterns, paint failure, and the prep history of prior bottom-paint jobs.
• Hard impact damage at the keel, the rudder, the prop, and the running gear.
• Through-hull condition — bronze patina vs. de-zincification, plastic through-hull cracking, sea-cock function.
• The trailing edge of the rudder and the cutless bearing for play.

Findings here cross-reference the hull and fiberglass repair guide. Deficiencies range from cosmetic spider cracks at hardware bases to load-path structural cracks worth walking away over — the gelcoat crazing and stress cracks spoke covers the cosmetic-vs-structural distinction in detail.

A handheld moisture meter — the surveyor's most-asked-about instrument — measures relative dielectric response in the laminate. Higher readings correlate with higher water content. The surveyor maps readings across the deck and the hull below the waterline, looking for patterns more than for any single number.

The patterns that matter:

• Around deck hardware. Stanchion bases, cleats, winch pads, windlasses. Elevated readings here point to bedding failure and water tracking down the fastener into a balsa- or foam-cored deck.
• At the deck-to-hull joint. A leaking joint puts water into the cabinetry and the cabin liner.
• At the waterline. A consistent band of elevated readings just at the waterline often correlates with the start of osmotic blistering — water working into the gelcoat from outside.
• Across the entire deck. A uniformly wet deck on a cored boat is a major-decision finding. Re-coring is one of the largest repair scopes a recreational boat can carry.

The CT freeze-thaw cycle turns wet core from a slow-progress problem into a fast-progress one. Water that sits in a cored deck through forty cycles of freezing and thawing between November and March expands and contracts, breaks the bond between the core and the skins, and the deck delaminates. This is why elevated moisture in a CT survey deserves more weight than the same reading on a Florida boat.

The honest caveat: moisture meters can read elevated on a wet-painted hull, a recently-launched boat, or a boat with residual moisture from a recent rain. The surveyor accounts for those conditions and re-reads where warranted. A single high reading is not a verdict — a consistent pattern is.

The engine inspection on a standard marine survey is visual and operational, not invasive. The surveyor does not pull heads, pull injectors, or run an oil analysis without specifically requesting it. What the surveyor does do:

• Visual inspection of the engine itself — block condition, paint, oil leaks, coolant leaks, raw-water leaks, exhaust soot, fuel staining at the lift pump and the secondary filter.
• Visual inspection of the engine mounts, the shaft coupling, the alignment indicator marks if present, the stuffing box, and the shaft seal.
• Engine start at the dock from cold — listening for hard starting, smoke color on first fire, any miss, any vibration that smooths out as the engine warms.
• Operational test of all engine instruments — tach, oil pressure, water temp, alternator output, fuel gauge.
• Cold-engine inspection of the exhaust elbow, the riser, the muffler, and the through-hull exhaust outlet.
• Inspection of the transmission for oil leaks, cooler integrity, shift cable adjustment, and at the sea trial the smooth engagement of forward and reverse under load.

The honest line on what the standard survey will not tell the buyer:

• Whether the engine has internal wear that has not yet surfaced — bearing wear, valve wear, cylinder wear. An oil analysis or a borescope inspection is the follow-up that does.
• Whether the head gasket is on its way out.
• Whether the turbo is at end-of-life.
• Whether the fuel injectors are clogged or worn.

For any of those, the surveyor will note “recommend specialist engine survey by a marine mechanic” — and on any engine with more than ~1,000 hours, more than 15 years, or any visible distress, the buyer should pay for that follow-up. The engine service pillar and the repower-vs-rebuild spoke cover what an engine specialist actually looks for. On diesel-specific failure modes the specialist survey looks deeper than the generalist will.

Electrical is the single largest source of survey deficiencies on Connecticut boats, and the largest source of insurance claims for fire. The surveyor inspects:

• AC shore power side. Inlet condition (heat damage, corrosion), ELCI/GFCI presence and function, polarity-indicator function, panel labeling, breaker condition, isolation transformer or galvanic isolator presence, and overall conformance to ABYC E-11. The shore power problems spoke walks the failure modes the surveyor calls out.
• DC house and start side. Battery condition, battery boxes (vented, secured, acid-resistant), main feed sizing, fuse and circuit protection, panel labeling, conformance to ABYC E-10 wire sizing and E-11 overcurrent rules.
• Bonding system. Bonding wire continuity to underwater metals, anode condition, evidence of galvanic activity at through-hulls and shaft. The power systems pillar covers the wider framework.
• Wire condition. Marine-grade tinned copper vs. solid copper, support at every 18 inches per ABYC, no splices in inaccessible spots, no green-tinged terminals, no melted insulation, no wire passing through holes without chafe protection.

Connecticut surveys frequently call out: outdated 30 A or 50 A inlets without ELCI, ungrounded AC outlets, undersized DC feeders, broken bonding wires at the rudder post or strut, missing battery box covers, and reverse polarity indicators that never worked. Most are inexpensive to correct individually. Together they decide whether the underwriter will bind the policy.

These five systems share a category in most surveys because they each carry a USCG or ABYC standard that triggers deficiencies the underwriter cares about.

Fuel system

Tank labeling, tank material and corrosion, fill and vent hose conformance to USCG fuel hose Type A1/A2 specifications, anti-siphon valve on fuel-feed lines, secondary filter and water separator, and grounding of the deck fill. Aluminum fuel tanks on older Connecticut boats are the most-flagged fuel-system finding — the saltwater bilge corrodes them from the outside.

Plumbing

Freshwater system, water heater function, all through-hulls with double-clamped hose, sea-cock function, head and waste system per the federal Marine Sanitation Device rules, Y-valve secured-closed in the Connecticut coastal No Discharge Area, holding tank vent. The plumbing pillar covers the system framework.

Exhaust

Wet exhaust hose grade (typically SAE J2006 R2), riser height above the static waterline, gooseneck or anti-siphon loop where required, hose support, and clamps. The exhaust elbow corrosion on a 7-to-10-year-old marine diesel is one of the most-common surveyor calls.

Steering

Hydraulic steering for cylinder leaks, helm-pump leaks, hose condition, mounting integrity. Mechanical or cable steering for cable tension and corrosion. Rudder bearing condition and play at the rudderpost.

LPG and CNG

If the boat carries cooking propane, the surveyor verifies the locker is vented overboard, the regulator and solenoid function, the leak-down test of the entire run, and the conformance to ABYC A-1. Failure here is non-negotiable — propane in a bilge is one of the deadliest fault paths on a recreational boat.

The surveyor confirms the electronics installed on the boat power on and run a basic self-test. The depth sounder reads the bottom. The VHF makes a radio check. The GPS acquires. The autopilot engages and disengages. The chartplotter draws charts. The radar transmits if a transmit-permit dock is reasonable to use.

The surveyor does not test the accuracy of the autopilot under load, the radar against a known target, or the chartplotter against a backup GPS. Those are specialist tests, not part of a standard survey. What the surveyor confirms is presence, age, condition, and basic function — and notes any obsolete equipment that an insurer will flag.

USCG-mandated safety gear is checked against the carriage requirements for the boat's length and use:

• USCG-approved life jackets — one wearable per person aboard, one throwable on boats 16 feet and over.
• Fire extinguishers — type and quantity per the 2022-and-later USCG rule (3-B:C or 5-B:C minimum, by boat length).
• Visual distress signals — currently dated.
• Sound-producing device — bell, horn, or whistle per boat length.
• Navigation lights — function, visibility range, proper colors, masthead and stern light geometry per 33 CFR Part 83 / Navigation Rules.

Expired flares and missing or expired fire extinguishers are the most-common findings. Both are easy fixes — and both are required for the underwriter to bind.

The dock-side inspection covers static condition. The sea trial covers operational behavior. A complete pre-purchase survey includes a one-to-two-hour trial out of the dock and back, ideally with the seller or the broker captaining and the buyer aboard.

The surveyor watches:

• Engine performance under load. Time to plane on a powerboat, top RPM, sustained cruise RPM. A diesel that will not reach wide-open-throttle by 100-200 RPM of its rated speed is overpitched, overloaded, or losing power.
• Smoke under load. Black at WOT (overfuel, overprop), blue (oil burn), white (combustion or water intrusion). The diesel failure guide covers what each color means.
• Vibration and noise. New vibration in a shaft, a bearing, or a coupling shows up under load and disappears at idle.
• Handling. Steering response in both directions, planing attitude, weather helm on a sailboat, the boat's ability to back out of a slip cleanly.
• Cooling. Water temperature stable at cruise. Raw-water flow at the exhaust. No coolant blowoff, no overheating.
• Charging. Alternator output coming up with RPM. Battery monitor showing real charge current.
• All electronics under way. GPS holding lock, depth reading correctly underway, autopilot engaging and tracking, VHF and chartplotter behaving.

The seller's responsibility is to deliver a boat that can complete the sea trial — fuel in the tank, batteries charged, all systems on. Cancelling the sea trial because the engine won't start, the steering is “a little off,” or the weather looks marginal is itself a finding. A boat that cannot sea-trial cannot be surveyed.

The deliverable is a written report, typically 30 to 60 pages long, that lands one to three days after the survey. The report contains:

• Vessel description. Identifying information, dimensions, build details.
• System-by-system findings. What was inspected, what was found, what is non-conforming.
• Deficiency list with severity codes. Most surveyors use one of two coding schemes — “findings/recommendations/safety items” or a numbered 1-2-3 priority — to separate the must-fix-before-launch items from the cosmetic notes.
• Overall condition rating. Typically “Excellent / Above Average / Average / Below Average / Poor,” with a specific narrative tying the rating to age, hours, and condition.
• Assigned fair market value. The surveyor's opinion of value, supported by comparables. This drives financing and the insurance binder.
• Estimated replacement cost. What it would cost to build or buy a replacement vessel of similar type and condition.

What the buyer does with the report:

• Reads it before doing anything else. Severity-1 findings — fuel-system non-conformance, propane, electrical fire risk, structural cracks, propulsion failure — are walk-away or material-price-renegotiation findings.
• Sends the relevant sections to a specialist if engine or rigging follow-up is warranted.
• Uses the deficiency list as the basis for the “buyer fix-it” punch list and the price renegotiation conversation with the seller.
• Provides the report to the underwriter for the insurance binder and to the bank if the purchase is financed. The companion to this conversation is the buying-a-used-boat-in-Connecticut guide and the insurance guide — both lay out how the report flows into closing.

The report is private to the buyer. The buyer pays for it; the surveyor is the buyer's agent in the transaction. The seller does not see it unless the buyer chooses to share findings.

Survey scheduling is dictated by haul-out availability. In the Connecticut yards from Greenwich to Stonington, travel-lift slots fill quickly between the launch rush in April-May and the haul rush in October-November. The practical calendar:

• Late winter (February-March). Surveys on stored boats — the boat is already on the hard, the surveyor can walk the bottom, but no sea trial is possible until launch. Useful for early-spring purchase decisions, with a sea trial scheduled after launch.
• Spring (April-May). The peak survey window. The boat is launching, the yard is busy, the schedule fills fast. Book the surveyor and the haul together six to eight weeks ahead. Spring commissioning works in parallel.
• Summer (June-August). Quieter on the survey calendar. Easier scheduling, full sea trial conditions, water warm enough to use every system. Often the best practical window for a thorough survey.
• Fall (September-October). Second peak. Buyers and underwriters want a survey before the boat goes on the hard for the winter. The yards are pulling boats around the surveyor's work.
• Late fall and winter (November-January). Surveys on stored boats again, no sea trial. Holding period for buyers who plan a spring launch.

For a boat that will winter outdoors, the buyer who completes the survey in summer holds the strongest position — sea trial done, full systems test done, and time to negotiate without a calendar pressure from the haul-out queue.

Helm does not perform marine surveys — the surveyor is independent of the seller, the broker, the marina, and the service provider, and Helm covers service work on the boats the surveyor inspects. What Helm coordinates is the work around the survey: scheduling the haul with a Connecticut yard sized for the boat, coordinating the sea trial with the broker and the seller, getting the boat ready (water on, power on, batteries charged, fuel in the tank) before the surveyor arrives, and — when the report lands — taking the deficiency list, costing the work, and handling the corrections that need to be done before the launch and before the underwriter will bind.

That work spans every cluster on the site — electrical, engine, plumbing, hull, canvas, refrigeration, electronics. The point of one number is that the buyer does not need to chain a list of trades together. Helm covers the boat from Greenwich to Stonington and on the Connecticut, Housatonic, and Thames rivers and inland lakes. The surveyor reads it; Helm fixes what needs fixing.