2019 Armstrong Marine 38 Monohull Aluminum Boat in Seattle, WA 98107 US
Built in 2019
38 Monohull Aluminum
2 Engines (2x Cummins)
38 feet
Diesel
Aluminum
Sentry is a purpose-built 2019 Armstrong Marine 38 Monohull combining welded-aluminum commercial construction, a large working deck and an enclosed all-weather pilothouse. Although designated as a 38-foot model, her transom working-platform configuration brings overall length to approximately 43 feet, with a substantial 13-foot beam.
Twin Cummins QSB6.7 diesels rated at 419 hp each are coupled to ZF 286A straight-drive transmissions. During the May 2025 survey sea trial, Sentry recorded approximately 21.5 knots at 2,400 rpm and 28 knots at 3,000 rpm in calm conditions.
Originally owned and operated by the Washington State Department of Natural Resources, Sentry was acquired by her present owner for overseas commercial projects.
Sentry offers a practical platform for commercial utility work, environmental or hydrographic survey, dive support, patrol, crew transport, research operations or conversion into a distinctive private expedition boat.
- Twin Cummins QSB6.7 425 IDI diesels
- Rated output: 419 hp each at 3,000 rpm
- Twin ZF Marine ZF286A reduction gears
- 2.208:1 gear ratio
- Electronic ZF engine and transmission controls
- Four-blade bronze propellers
- 1¾-inch stainless-steel shafts
- Tides Marine SureSeal shaft seals
- SeaStar hydraulic steering
- Side-Power 24-volt bow thruster
- Lenco trim tabs
- Approximately 15.5 knots at 2,000 rpm
- Approximately 21.5 knots at 2,400 rpm
- Approximately 28 knots at 3,000 rpm
The enclosed pilothouse provides excellent visibility and direct access to the working decks.
- Twin Garmin multifunction displays
- Garmin GPS and chartplotting
- Garmin radar
- Garmin depth sounder
- Garmin hydraulic autopilot
- Two Garmin fixed-mount VHF radios
- Ritchie magnetic compass
- Golight remote searchlight
- Fusion marine stereo
- Electronic Cummins engine instrumentation
- Dedicated navigation and work surfaces
- Large aft working deck
- Full walk-around side decks
- Heavy-duty welded-aluminum perimeter railings
- Foredeck working area
- 24-volt electric drum-style anchor winch
- Galvanized Vulcan-style anchor
- Galvanized anchor chain
- Shurflo raw-water deck-washdown pump
- Three 24-volt electric bilge pumps
- Reversible fuel-transfer pump
- Transom dive/swim platform
- Platform-mounted reboarding ladder
- Navigation, anchor and work lighting
- Forward berth with 3 bunks
- Enclosed head compartment
- Electric freshwater macerator-flush toilet
- USCG Type III holding-tank system
- Webasto diesel forced-air heater
- Three Heater Craft engine-supplied hydronic heaters
- Interior storage and work surfaces
- 24-volt primary DC system
- 12-volt equipment circuits
- 120-volt AC system
- Ten Lifeline AGM batteries reported in the 2025 survey
- Separate port and starboard engine-start banks
- Two house-battery banks
- Victron Energy MultiPlus inverter/charger
- 70-amp, 24-volt charging output
- 3,000-watt, 120-volt inverter output
- Victron Orion 24-to-12-volt converter
- Charles ISO 3.6 kVA isolation transformer
- SmartPlug 30-amp, 125-volt shore-power inlet and cable
Available documentation includes:
- May 2025 condition and valuation survey
- Historical engine-service information
- Cummins maintenance information
- Yard invoices
The May 2025 survey identified maintenance items involving the port-engine seawater pump, hydraulic steering system, autopilot rudder-angle sender, rudders and propellers. The bow-thruster anode was subsequently replaced by CSR Marine.
Sentry was partially disassembled to ship overseas. Plans changed, and so Sentry is presently stored ashore at a secure yard in Ballard/Seattle.
The following equipment was removed, packed and represented as stowed aboard:
- Mast and mast-mounted electronics
- Propellers
- Trim tabs and trim-tab rams
- Transom-mounted transducer
- Transom dive/swim platform
- Aft seat and associated transom structure
Minor reinstallation, recommissioning and testing will be required before normal operation.
The Company offers the details of this vessel in good faith but cannot guarantee or warrant the accuracy of this information nor warrant the condition of the vessel. A buyer should instruct his agents, or his surveyors, to investigate such details as the buyer desires validated. This vessel is offered subject to prior sale, price change, or withdrawal without notice.
Price History
| Date | Event | Price |
|---|---|---|
| 8/18/26 | Initial price | $495,000 |
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 2019 Armstrong Marine 38 Monohull Aluminum | ||||||
|---|---|---|---|---|---|---|
| Price | $495,000 | $495,000 | $649,000 | $109,999 | $103,900 | $38,000 |
| Location | Seattle | Seattle | Anacortes | La Conner | Anacortes | Belfair |
| Nominal Length | 38' | 38' | 33' | 26' | 25' | 18' |
| Engine Make | Cummins | Cummins | Mercury | Honda | Mercury | Tohatsu |
| Total Engine Power | 419 hp | 419 hp | 400 hp | 250 hp | 225 hp | 60 hp |
| Days on Market | 15 | 1 | 489 | 36 | 321 | 342 |
| Get in touch |
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Meet the Broker
Address
Boat Location
Contact W S Yacht Brokers - Seattle about 2019 Armstrong Marine 38 Monohull Aluminum
2500 Westlake Ave N, Suite D, Seattle, WA, 98109
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