1973 Bertram 31
$150,000
Boat in Fajardo 00738 PR
Built in 1973
31
2 Engines (2x Yanmar)
30.6 feet
Diesel
Fiberglass/Reinforced
Dual Yanmar 4LHA-STP 240HP Engines
Generator Northern Lights 5kw
1 Cabin and 2 Heads
Refrigerator
Microwave
Cockpit table.
Price History
| Date | Event | Price |
|---|---|---|
| 3/21/26 | Initial price | $150,000 |
1973 Bertram 31 Video Tours
Boattest.com Review
Overview
This review examines the impact of repowering a 1981 Bertram yacht with modern Yanmar 6LP series diesel engines. Originally equipped with two 330 horsepower Mercruiser 454 gasoline engines, the vessel underwent an upgrade to twin Yanmar 6LPA STP II diesel engines. This transition not only improved efficiency and operational security but also added value by reducing weight and fuel consumption while freeing up valuable engine room space.
Engine Design and Installation
The Yanmar 6LPA STP diesel engine features a compact design that fits easily within the existing engine stringers of the Bertram, creating an additional 3 inches of space on the inboard side and sufficient room on the outboard side to accommodate a small generator. The aft end of the engine also gained 5 inches of clearance. Despite its compact profile, the engine maintains accessibility to key maintenance points, including oil dipsticks on both sides, a spin-on oil filter, a secondary fuel water separator filter, and a primer pump located on the inboard side. The heat exchanger is positioned high on top with hoses routed around the front, while the stainless steel mixing elbow, wet turbocharger, compressor, and air intake are arranged efficiently at the aft end. The transmission cooler and hoses are located below these components. This layout significantly improves space utilization compared to the original large-block gasoline engines, allowing easier access to batteries and additional equipment placement.
Engine Specifications and Performance
The 6LPA STP is a 6-cylinder, 4-stroke, 4.1-liter turbocharged diesel engine equipped with an intercooler and a fresh water cooling system, which is considered optimal for marine applications. It delivers a continuous rating of 255 horsepower at 3600 RPM and a maximum output of 315 horsepower at 3800 RPM, weighing 899 pounds. The repowered Bertram achieved planing in 5.3 seconds and reached 30 mph in 8.4 seconds. At maximum RPM (3911), the engines consumed 29.4 gallons per hour, providing a range of 254 miles at 37.4 mph. Operating closer to the continuous rating at 3500 RPM, fuel consumption dropped to 23.3 gallons per hour, extending the range to 292 miles at 34 mph. The most economical cruise speed was 20.1 mph at 2250 RPM, yielding a range of 401 miles. These figures highlight the improved fuel efficiency and extended cruising capabilities afforded by the diesel repower.
Operational Benefits and Owner Experience
The repower delivered significant benefits including reduced engine weight, increased available space, and easier maintenance access, all contributing to safer and more economical operation. The owner noted that the only unexpected cost was repainting the waterline due to an overall weight reduction of approximately 3,000 pounds from the new engine installation. The diesel engines provide peace of mind through reliable and efficient performance, promising many years of enjoyable boating. The reviewer also emphasizes the advanced engineering of Yanmar's latest diesel models and recommends considering Yanmar power for both repowers and new yacht specifications.
Overview from around the web 1973 Bertram 31
Customers often praise the 1973 Bertram 31 for its classic design and exceptional craftsmanship
Many owners highlight its seaworthiness and stability, making it a reliable choice for both fishing and cruising. The spacious cockpit and ample storage are frequently mentioned as standout features, allowing for comfortable outings on the water. Owners also appreciate the powerful performance of the twin-engine configuration, which provides a smooth ride even in varying sea conditions. The timeless aesthetic of the boat, with its iconic lines and sturdy construction, has garnered significant admiration from both seasoned mariners and newcomers alike. Additionally, users often note the strong community and support for Bertram owners, making it easy to find parts and maintenance advice. Overall, the 1973 Bertram 31 is celebrated as a classic choice that combines performance, durability, and style, creating lasting memories for its owners.
The Biggest Pros and Cons
The 1973 Bertram 31 is a classic model that has earned a reputation for its solid construction and seaworthiness, making it a favorite among boating enthusiasts. Here are some pros and cons of this iconic vessel:
Pros
Durability and Build Quality: The Bertram 31 is known for its rugged fiberglass hull and robust construction, which contribute to its longevity and ability to withstand rough seas.
Performance: With a deep-V hull design, the Bertram 31 offers excellent performance, providing a smooth ride and good handling in various water conditions.
Versatile Use: This boat is adept at both fishing and cruising, making it versatile for different activities. It’s often equipped with ample storage for fishing gear and amenities for comfortable cruising.
Classic Style: The classic design and aesthetic appeal of the Bertram 31 have stood the test of time. Its traditional lines are attractive to many boaters who appreciate vintage craftsmanship.
Resale Value: Due to its legendary status, the Bertram 31 tends to retain its value well in the market, making it a worthwhile investment for boaters.
Spacious Cockpit: The layout provides ample space for fishing or relaxing with friends and family, making it a great platform for social interactions.
Cons
Maintenance: Older models may require more maintenance and repairs, particularly if they haven’t been updated with modern systems or equipment. Parts may also be harder to find for older designs.
Fuel Economy: The Bertram 31, particularly with older engines, may not be the most fuel-efficient option, leading to higher operational costs compared to newer models.
Limited Cabin Space: While the cabin is functional, space can feel cramped for larger groups or prolonged stays, especially if you're accustomed to modern layouts with more living space.
Weight: Its solid construction means the boat can be heavier than some contemporary alternatives, potentially affecting trailering and fuel efficiency.
Technology: A 1973 model may lack the modern technology and amenities found on newer vessels, such as advanced navigation systems and contemporary comfort features.
Made For
The 1973 Bertram 31 is ideal for avid fishermen and boating enthusiasts seeking a classic vessel with a proven track record. This iconic model caters to those who appreciate timeless design combined with robust performance. Whether you are a seasoned angler looking for a reliable sportfishing boat or a weekend warrior wanting to enjoy coastal cruising and watersports, the Bertram 31 offers versatility and durability. Its spacious cockpit is perfect for fishing or entertaining guests, while the comfortable cabin ensures a pleasant retreat when docked or anchored. With its impressive hull and well-regarded seaworthiness, this classic boat is designed to tackle both calm and rough waters, making it an excellent choice for adventurers who seek both reliability and style. The 1973 Bertram 31 is for those looking to create unforgettable memories on the water, whether casting lines or relaxing with family and friends.
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 1973 Bertram 31 | |||||
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| $150,000 | $110,000 | $75,000 | $69,900 | $274,900 | $349,000 |
| Fajardo | Ponce | San Juan | San Juan | San Juan | Fajardo |
| 31' | 46' | 42' | 42' | 35' | 45' |
| Yanmar | Detroit Diesel | Detroit Diesel | Detroit Diesel | Caterpillar | MAN |
| 240 hp | 550 hp | 375 hp | 375 hp | 450 hp | 900 hp |
| 936 | 221 | 391 | 31 | 615 | 31 |
Meet the Broker
Address
Boat Location
Contact Wally Castro Marine about 1973 Bertram 31
Safe Harbor Marina Puerto Del Rey, Fajardo, 00738
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