BCS Trim Tab
Trim tabs are an essential component for any yacht. They improve performance, helping to increase speed, reduce pounding and on smaller boats offset prop torque. They help the vessel run more efficiently, reducing fuel consumption and engine laboring and eliminate “squatting.” But more importantly, they increase safety by improving visibility and handling along with reducing wake size and hull stress.
However, years of use and prolonged exposure to salt water can take a toll on their ability to function properly as was the case with an 85’ Ferretti that was hauled at Lauderdale Marine Center.
That is when our hydraulics team was called in to work on the BCS hydraulic trim tabs. Upon close inspection, we found that two of the four trim tab cylinders were corroded beyond repair and needed to be replaced. Because of manufacturer’s long lead time, we decided that we would machine new rods, barrels and re-build the cylinders in-house, using our machine shop, Straight Line Marine.
Corrosion in Barrel
The corrosion we found on the inside of the barrel was caused by salt water intrusion as a result of failed seals. Once the components were machined, we were ready to assemble the new hydraulic trim tab cylinders and re-install in the yacht. Unlike common trim tab cylinders, the BCS model does not use hydraulic hoses to distribute the hydraulic fluid to operate the trim tabs. The fluid is dispersed through a small pin hole in the transom bracket assembly. A clever design that eliminates hose failure external to the transom. However this creates a tricky install.
Pin Hole
The pin has multiple O-rings and requires a special touch to avoid pinching during installation. Great care must be taken in the removal of the old hydraulic trim tab cylinders and the re-installation of the new ones. Damage to the assembly as a result of scratching or scoring the unit would cause them to leak and render the trim tab cylinders useless.
We see these types of nuisances all the time. It takes a team of highly experienced hydraulics technicians to properly diagnosis the problems and take the appropriate actions to correct them.
