Five Things You Should Know Before You Buy a Used Grand Banks

Grand Banks are excellent boats. Their construction quality is very high, they age well, and their reputation is strong. All of those factors will help when it comes time to sell the boat. The Grand Banks 42 is one of the most successful boats ever introduced. For these reasons, the GB’s are great candidates for those looking for a quality cruising boat in the used market. We have serviced and refit many Grand Banks over the years, and we have learned where to look for potential problems. Here are our top five.

1. Fuel Tanks

Grand Banks fuel tanks were made out of steel. They last a long time unless they are exposed to water. Exposure to water sometimes happens from leaks in the deck fills above the tanks, or from water sprayed off of the shafts at the stuffing boxes. The tanks gradually rust until the pitting becomes so severe that leaks develop. Most of the tank will appear to be in great shape, and the deterioration might be hidden in a difficult to access area. A borescope can be helpful to look around corners and into tight spaces. At best the process involves removal of the generator, cutting the tanks apart in place, and replacing them with multiple smaller tanks so that they will fit through the opening. Replacement as single tanks requires moving the engines. Aluminum is the most common choice for replacement tanks. Fuel tank replacement on these boats will cost tens of thousands of dollars…we know, we have replaced many of them.

Cutting apart the steel tanks so that they can be removed in small pieces. Old tank removed.
New aluminum tanks ready for installation. New tanks in place. Note inspection ports and sight tubes.


2. Shaft Alignment

Shaft alignment can be a serious problem. During the survey, a minor issue, such as a shaft that is hard to turn or bearing unevenly worn will often be discovered. Most brokers and many surveyors will point to a worn or swelled cutless bearing, and will assume that the cost to remedy the problem will be $500 or less. We have found that in many cases the bearings are worn because the struts are out of position and need to be re-aligned. This repair requires removal of the shafts, removal of the struts, and repositioning the struts in line with the shaft log and engine. In addition, there is a good possibility that the shafts are excessively worn where they ride in the bearings, calling for shaft replacement. The cost to replace the shaft and reposition the strut can be very high.

Excessive shaft wear caused by poor alignment ruined this shaft. Using a laser to realign the struts. After strut work and shaft replacement, this shaft turns freely by hand.


3. Teak Decks

Teak decks are often overlooked. There are two areas of concern: the condition of the wood plugs that cover the screws, and the condition of the black seam compound. If the screws are exposed, moisture can work its way down into the deck structure, eventually causing major damage. Stains in the headliner might be telltale indicators that moisture is getting into the sub-deck, as shown in the photo below. The screws must be removed, the holes bored slightly deeper, and the fasteners screwed in. A new teak plug is then glued in place and trimmed. The seam compound gradually loses its adhesion and elasticity, allowing water to get under the teak, where it finds its way to the screw holes. Re-caulking the deck requires many man hours of labor to reef out all of the old seam compound, clean the seams, and prep them for new seam compound. The new compounds retain their elasticity longer than the older formulations. If you are having this work done, make sure the yard uses a “bond breaker” per the caulking manufacturer’s recommendations. These problems can be easily identified, and the cost to restore the integrity of the teak decking can be quantified before making a purchase offer.

Plugs have worn through, exposing screw heads. Caulking pulling away from edges of seams.
Stains on the forward cabin headliner were caused by water getting into the sub-deck through the deck screws and caulking. We caught this before there was too much damage to the plywood core. Seams have been cleaned and sanded, and new caulking is being applied.


4. Engines

The GB 42’s came with a wide range of engines, including 135 HP Lehmans, 210 HP Cummins, Catepillar 3208’s from 210 HP to 375, Caterpillar 3126, and others. Performance, longevity, resale value, and service access are greatly affected by model selection and should be a factor as you compare available boats. Fuel economy is greatly misunderstood when comparing different engines. Additionally, there are protocols for running larger engines at lower RPM. Within the Caterpillar 3208 range, the HP rating can impact the longevity of the engine. Even if one of these engines is sound internally and comes back with good oil and coolant analyses, the cost to service the peripherals (water pumps, turbo, intercooler, transmission cooler, etc.) can be surprisingly high and must be taken into account as you project costs.

These old Lehmans still have a lot of life in them. They provide good fuel economy and create considerably more open space in the engine room that the big CATs. Components have been removed for service on this 3208.
Painting an engine can be very labor intensive. While components are removed they can be painted more efficiently. Reassembled and ready for cruising.


5. Battery Configuration

Battery configuration on the most Grand Banks is not well suited for cruising, especially if you anchor out. Most of these are set up with two equal banks of batteries. A better set up involves one bank that is dedicated for engine starting, with batteries selected to provide the optimal amount of cold cranking amps needed for starting loads. The second bank is optimized with deep cycle batteries for “house” demands, providing the needed amount of amp hours gradually drawn over a longer period of time. This situation factors into the process of installing an inverter and is often overlooked when estimating the cost of installation. There is however, a good way to reconfigure the older battery layout and add the capacity needed for an inverter. Matching the charging capacity of the boat to the amp hours needed to recharge the batteries must be worked out mathematically so that the time required to recharge a large battery bank is reasonable.

This new bank of deep cycle AGM batteries will provide far greater capacity than the original set up.



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