Horizon Shipbuilding in Bayou La Batre, Alabama saves time and money with a new VO mount installation tool
Situated in the far southwest corner of Bayou La Batre, Alabama, sits a top ship and boat building company, Horizon Shipbuilding. For more than 15 years, Horizon has been building an array of impressive vessels, ranging from 30-ft. boats for the U.S. Navy to 200-ft. supply vessels. The family run business covers 12 acres with every available space dedicated to building, repairing and maintaining boats. Horizon Shipbuilding is a full service company whose capabilities include design, construction, operation, maintenance and repair. One of the most common boats Horizon builds are the 140-ft. towboats, most of which end up pushing barges – sometimes as many as 30 at a time – up and down the Mississippi River.
To move so many barges at one time, modern towboats need plenty of horsepower, and one result of these powerful high torque engines is they can produce harmonics: vibrations produced by the firing and internal moving parts of the engine that adds wear and tear to the vessel. To ensure that doesn’t happen, vibration oscillator mounts must be installed between the engine and engine mounts. Vibration Oscillators (VO) combat the back and forth vibrations produced by the high horsepower engines.
Installing VO mounts is a big job considering that each engine can weigh 18 tons. Roger Oliver the 10 year Production Superintendent at Horizon, who is responsible for “everything in the yard,” knows this job all too well. “By the time you get them in, get everything aligned, pulled back out and drilled and set back in there, you’re looking at a three day evolution. We used to have to take the engines right out of the boat, make the holes, and then set them back in.”
To install VO mounts, each engine has to be lowered into the engine compartment, lined up on the guide posts, holes marked, then hoisted back up and out so 24 holes through A36 material could be drilled with a magnetic drill and mounts installed. Then the tedious task of realigning the engine back on the guides. After which it is lowered down and finally secured into place. “When realigning these engines we shoot for a tolerance of zero, but the tolerance on an engine like this is .002” said Oliver.
For Horizon, the ability to fully design and construct a boat from the ground up is one of the keys to their success. And with as many as 14 newbuilds going on at a time, the 230 plus employees at Horizon must look for every avenue to save time while exceeding customer expectations. Oliver was investigating a better way to drill the holes for the VO mounts, and searching for a “small skinny drill,” he eventually came across a low profile magnetic drill from Hougen Manufacturing called the HMD150.
Intrigued by its small size and large hole capacity, he felt this might be just the ticket they needed to save time. Oliver contacted Fred Buish from Tooling Concepts in Mobile, Alabama and had him out to go over the Hougen drills. Together Fred and Roger pulled the prints to installing the VO mounts and discovered they could raise the powertrain up just 10-in. while keeping it aligned on the guide posts. The HMD150 drill was only 7-13/16-in. high which would work perfect for drilling the holes under the engine. The Hougen HMD150 is a low profile magnetic drill weighing 22.7 lbs. It has the capacity to drill holes up to 1-3/8-in. diameter and 1-in. deep using the tool-less RotaLoc Plus annular cutters. To achieve the low profile, the HMD150 drill uses a right angle Hougen motor, high power gearing and a quill feed arbor system which incorporates positive slug ejection. Roger was excited that the drill would work but the holes had to be 1.5-in. deep, and standard cutters for the HMD150 are 1-in. deep. Oliever put in a request and asked if Hougen could make custom RotaLoc Plus tools in the size of 15/16-in. x 1.5-in. deep. Fortunately Hougen had a handful of 1.5-in. deep cutters already on the shelf and immediately sent them to Horizon.
When it came time to install the VO mounts, Roger and the crew at Horizon put their new method to the test. Once the holes were marked, they hoisted the engines 10-n. while they stayed aligned on the guide posts. An HMD150 was brought in to drill down to the max depth of 1-in. Then the crew put the 1.5-in. long RotaLoc Plus cutter in the drill, placed the cutter back into the existing hole that had just been drilled and finished drilling out the last half inch. They did this to all 24 holes. Mounts were secured, the powertrain was lowered back down, bolted into place and was ready to go into service. ”It’s much faster. We don’t have to pull the engine out. Once the alignment is done it takes just four hours for the job,” said Oliver. As comparison, the job used to take three days. “We like the HMD150 because of its small size but not only that, it drills quite well. For its size it packs quite a punch and will get right on through the material.”
(As published in the November 2012 edition of Maritime Reporter - www.marinelink.com)