Archive | Pitting

Replacing shafts on a Quantum Stabilizer system

By Chris Brown on July 29, 2014 in Hydraulics, Pitting, Quantum Stabilizer System, Stabilizers

While working on a Quantum Stabilizing system on a ABS Class 154 foot Richmond, we found that the stabilizer shafts had significant crevice corrosion where the lower lip seal rides. The lip seals on a hydraulic shaft or rod need a smooth surface or the sea water will leak in causing a failure of the bearings. The model of Quantum Stabilizer system used on this vessel was a Zero Speed ™ known for its ability to stabilize a vessel underway or at anchor.

Shafts from a Quantum Stabilizer System

We were able to repair one of the shafts by cladding over the area where the corrosion occurred. Cladding or shaft weld-over, is the process of repairing a worn or damaged area on a shaft. This type of work is done by our on-site machine shop, Straight Line Marine, which is the only shop in Florida that is ABS approved to perform this work on this class of boat.

However, the other shaft had corrosion that ran too deep so it was condemned and a replacement shaft was ordered.

Once the cladding process was complete and the replacement shaft received, we were able to re-install the stabilizer back in the vessel helping to ensure a smooth and comfortable journey for all aboard.

Maxwell Windlass Repair using Belzona

By Chris Brown on July 2, 2014 in Hydraulics, Pitting, Windlass

Pitting and corrosion before repair

Belzona applied over repair

While performing routine maintenance on a 110 foot Broward yacht’s Maxwell anchor windlass, we did a full tear-down and inspection. When we disassembled the Maxwell windlass, we found excess/severe pitting and corrosion in the cover body. Most marine aluminum equipment suffers from this type of corrosion over time. Unfortunately the part was so old that Maxwell did not have replacement parts readily available. The part was cast and very complicated so machining a replacement part was not feasible or economical.

In order to remedy the situation, we used a product call Belzona. It is a 2-part repair composite for metal repair and resurfacing based on solvent free epoxy resin reinforced with silicon steel alloy. This repair material will not corrode and resists a wide range of chemicals. It is easy to mix and apply without the need of specialist tools and can be machined using conventional tools.

The part was first sandblasted clean and prepped. We apply the Belzona to the repair area on the Maxwell windlass similar to applying frosting to a cake. Once it cures the material machines like aluminum. We then put the unit in the lathe where the cutting tool cuts the ID (inside diameter) of the windlass part. What we are showing in the accompanying pictures is the process half completed so what you are seeing is a smooth round surface under and to the left of the cutter and the frosting mix that is about to be cut to the right of the cutter.

Unit in the lathe where the cutting tool cuts the ID (inside diameter)

The final step in the process is powder coating before re-installation back onto the vessel. With this type of repair, the owner should expect many more years of use of this Maxwell windlass.

Machine Shop and Hydraulics Shop under one roof – convenience for the customer

By Chris Brown on April 15, 2014 in Cylinders, Hydraulics, Pitting

Hydraulic Cylinder Rebuild – Pitting on the Rod requires replacement

It is a fairly common occurrence for us to find pitting on hydraulic cylinders or shafts that we work on in our shop at High Seas Hydraulics. This is typically caused by corrosion from salt water, crevice corrosion or as a result of cheap stainless steel material used in fabrication. The lip seals on a hydraulic shaft or rod need a smooth surface or the hydraulic fluids will leak out causing a reduction in the performance of the units and, in this case, hydraulic fluid leaking into the ocean.

To fix this problem on large propeller shafts, we would perform a process called cladding at our machine shop, Straight Line Marine. Cladding or shaft weld-over, is the process of repairing a worn or damaged area on a propeller shaft or rudder shaft. Stainless steel shafts can be damaged by excessive wear in contact areas, such as bearings or seals, due to long life or misalignment. Shafts can also be damaged from crevice corrosion or stray current corrosion. Straight Line Marine is the only shop in Florida that is ABS approved to perform this type of work. Replacing a large shaft could cost up to $25,000 each shaft, depending on the size. However, the cladding repair is only a few thousand dollars. For smaller shafts like sailboat shafts or hydraulic cylinder rods, we would simply buy new rod material and scrap out the old rods.

Crevice Corrosion on Shafts will destroy a Lip Seal System

The convenience of having a machine shop Straight Line Marine and hydraulics shop (High Seas Hydraulics) under one roof ensures our customers that they can get the right level of expertise no matter how big or how small their needs.