Washington Island, Wisconsin -
Watching Mike Kahr drive steel sheets with his reciprocating hydraulic hammer yesterday, and noting the relative ease with which the sheets were driven into the bottom, caused me to think back on some of the other projects we've had over the years.
Many feet of steel sheeting were driven, especially at Northport around 1982-3, when John Fitzgerald and his crew extended the Northport Pier by some 70 feet, adding a slight wedge to the north corner, the design intention being to lessen lake swell action curling around the northern side of the pier. That project came 11 years before the stone break wall was constructed with the aid of a Wisconsin DOT grant to Door County. Prior to the breakwater of 1994, the pier projected unprotected approximately 100 yards from shore, an obstacle to waves and moving ice.
Welder Mike Brown fabricates the corner piece from two sheets that can't be interlocked due to the degree of bend. In the background, Mike Kahr uses a hydraulic hammer to drive steel sheets. |
In order to accomplish the work of extending the pier in 1982, contractor Fitzgerald rented a diesel hammer. The solid, heavy steel head slid up and down in a steel framework, powered at the bottom of the downstroke by an explosion (combustion chamber) that caused it to rise back up several feet in the air, then drop again to repeat the process. The hammer head rig was positioned over the sheet being driven, and the whole works was held in place by a crane. Before that project, John used a pile driver block that was repeatedly raised by crane cable 8-10 feet and then let free-fall, with gravity doing the pounding, one tap at a time.
The hydraulic hammer arrangement used today by Mike Kahr is rapid and flexible. It seems to do a good job until progress is stopped by a large stone, and that was the case with several sheets on the inside of the slip. Another improvement in equipment, too, is that this hammer head can be shifted quickly from one sheet to another by just lifting the arm of the excavator. Kahr can use the excavator arm to pull or push plates to achieve the best vertical alignment. And, it takes only minutes to detach the breaker head and install the backhoe's bucket for other work.
Contractor John Fitzgerald extended the Northport pier, shown here in the summer of 1982 with a diesel hammer for driving sheets. |
In all, over 200 linear feet of pier were enclosed with sheeting at Northport in 1982. Here, worker Don Beckstrom cuts sheets to length. Some sheets were driven in water depths of 16 feet. |
Myron LaPlant operated machinery for John Fitzgerald. |
With a greater number of motor coaches, campers, trailered pleasure boats and heavy trucks, as well as an increase in general tourism traffic in summer, by the 1970s the gravel pile was no longer a good option.
Arni Richter wanted to install a hydraulic ramp strong enough to hold a loaded semi. R. A. Stearn Naval Architects, Sturgeon Bay, supplied engineering for the hydraulics (based, in part, on experience gained with engineering early Travelift units) and my father, Harry Purinton, provided a fair amount of time - some personal and some through R. A. Stearn where he worked with hull and structure - to design the ramp details and footings.
Once steel was ordered, ferry captain John Hanlin cut and welded, and assembled the ramp in a level opening near the bike shop garage. Kermit Jorgenson operated Njord Heim's crane to lift, and then turn over, the ramp. Few pieces of equipment were available on the island at that time for such tasks, whereas now there are numerous loaders and excavators with the lifting capacity and reach for such an operation.
While the steel work progressed, a hole was excavated near the water for footings. By late June, the foundation was ready to receive the ramp, and by the weekend of the Fourth of July, the ramp was in a pinned position, ready to be driven across, but it took several more days to complete electrical connections (Earl Frank was the electrician) and pipe the hydraulics (work by ferry crew), making the ramp fully adjustable at last.
During the construction of the foundation, ferries landed at the end of the south dock. Today at that location, a wider, longer and heavier ramp is available, installed in 2001. The rams on this newer ramp permit adjustment under heavy loads, whereas the original 1975 ramp was incapable of adjustment under load, due to smaller rams and lower pump pressures.
Kermit Jorgenson operated the crane as Dick Hanlin offered advice. Eldred Ellefson, who loaned the crane from Njord Heim, observed in foreground as the 20 x 20 ft. ramp was turned over. |
Ferry captain John Hanlin, who was also skilled working with steel. |
Such improvements as shore ramps are quickly absorbed into the operation, becoming one more slight adjustment before loading or unloading, and a major adjustment when the load is long, low or exceedingly heavy. The general public may not realize the benefits, but the advent of one, good hydraulic ramp on the island meant quicker and easier loading of each ferry using the bow ramp (the C. G. Richter still required side loading, until about 1989 when the Washington (dis)placed it into passenger only status). In a few years' time, by 1980, a similar ramp was installed at Gills Rock, and early in the summer of 1985, the north ramp at Northport was installed. In time, smaller ramps also went in at the island's south landing, and at Northport's winter landing slot. All later ramps were based on the original 1975 structural design, with modifications made as needed.
- Dick Purinton
1 comment:
I have fond memories of the extension of the pier at Northport. That fall, we took a short vacation (Mom and Dad took us out of school) to stay at the Eller cottage, and the pier was surrounded by metal walls holding back the water, but hadn't been filled in yet - my brother and I had a blast running around amongst the rubble rock. Thanks for the photos!
Lisa Prindle
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