ALL IN THE SAME BOAT
Using the right tool can save big time. Horizon Shipbuilding proved this when its new magnetic drill slashed the engine mounting job in its boat assembly from three days to four hours.
Nestled in the far southwest corner of Bayou La Batre, Alabama, sits one of the top ship and boat building manufacturers. For over 15 years Horizon Shipbuilding Inc. has been turning out some of the top vessels to grace the water, from small 30 ft boats for the U.S. Navy to 200 ft supply ships. Horizon is a full service company whose capabilities include design, construction, operation, maintenance and repair. This family-run business covers 12 acres, with every available space dedicated to building, repairing and maintaining boats.
One of the most common boats Horizon builds are the 140 ft towboats that are specifically designed to push or pull barges. Most of these towboats end up pushing large barges up and down the Mississippi River. Barges are the favored mode of material transport along the Mississippi River because of the sheer amount of product that can be moved at one time. A single standard barge is 195 ft long, 35 ft wide and weighs up to 1,500 tons. Compared to trucks and rail, these flat-bottomed giants move more goods and are less expensive to operate.
These towboats can push as many as 30 barges at one time. To move and guide so much cumulative weight at once, modern towboats need plenty of horsepower. Most of these vessels are built with two diesel engines and, in fact, to see boats with 3,000 hp or more per engine is not uncommon. The engines produce the torque and power needed to safely direct the barges.
One of the characteristics of these powerful high torque engines is that they can produce harmonics, which are vibrations created when the cylinders fire and convey torque to the crankshaft, causing it to deflect back and forth. At certain engine speeds the torques from the cylinders exert force on the crankshaft at the same time it is vibrating back and forth, creating a harmonic movement that can stress and damage the crankshaft and cause it to fail.
To ensure this doesn’t happen, vibration oscillator (VO) mounts must be installed between the engine and engine mounts. Vibration oscillators combat the back-and-forth vibrations produced by the high horsepower engines. Installing VO mounts is a big job, considering that each engine weighs 18 tons and is over 16 ft long and 11 ft high.
Roger Oliver has been the production superintendent for ten years at Horizon. He is responsible for “everything in the yard,” and he knows this job all too well. “By the time you get the mounts 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 of these massive engines must be lowered down into the engine compartment, lined up on guide posts so the holes can be marked, then hoisted back up and out of the way so that 24 holes can be drilled through A36 material with a magnetic drill to install the mounts. This process is followed by the tedious task of realigning the engine back on the guides, then lowering it down and finally securing into place. “When realigning these engines we shoot for a tolerance of zero, but the tolerance on an engine like this is .002 in,” explains Oliver.
For Horizon, the ability to fully design and construct a boat from the ground up is one of the keys to their success. With as many as 14 builds going on at the same time, the 230-plus employees on the yard must look for every avenue to save time while still exceeding their customer’s expectations.
Oliver had always felt there was a better way to drill the holes for the VO mounts. While searching for a “small skinny drill,” he eventually came across a low profile magnetic drill from Hougen Manufacturing Inc. (Swartz Creek, MI) called the HMD150 that weighs only 22.7 lb but has the capacity to drill holes up to 1-3/8” in diameter and 1 in deep using toolless RotaLoc Plus™ annular cutters. To achieve such a 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.
The production superintendent was intrigued by this small size and large hole capacity and felt this mag drill might be just the ticket they needed to save time. He contacted Fred Buish, the sales manager from local distributor Tooling Concepts & Industrial Supply (Mobile, AL), and had him stop in to go over the Hougen drills.
Oliver inquired about the HMD150 and asked Buish whether or not he thought this drill might be the answer he was looking for. Together they pulled the prints to installing the VO mounts and discovered that they could raise the powertrain up just 10 in while keeping it aligned on the guide posts because the HMD150 drill was only 7-13/16 in high, which would work perfectly for drilling the holes under the engine.
Oliver was excited that the drill would work, but the holes had to be 1½ in deep. Standard cutters for the HMD150 are 1 in deep. Oliver put in a request and asked if Hougen could make custom RotaLoc Plus tools in the size of 15/16 in diameter by 1½ in deep. Fortunately the company had a handful of 1½ in deep cutters already on the shelf and immediately sent them down to Horizon.
When it came time to install the VO mounts, Oliver and the production crew put their new method to the test. Once the holes were marked, they hoisted the engines 10 in while they stayed aligned on the guide posts. An HMD150 was brought in to drill down to the maximum depth of 1 in. Then the crew put the 1½ 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 ½ in.
They repeated this on all 24 holes. Mounts were secured, the powertrain was lowered back down, bolted into place and the unit was ready to go into service. “This is much faster. We don’t have to pull the engine out. Once the alignment is done it only takes four hours to complete the job,” says Oliver. When he compares this against the three days one job used to take, only taking four hours is a huge time savings. “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 go right through the material. That’s what I like, American made products that perform.”
Safety is always a concern at Horizon and, when moving 18 tons around, you must always be on your toes. Because this drill is lighter and easier to move around, it cuts down on moving these huge engines in and out of the boat. This, in turn, cuts down on the lift time and crane time that are required for this job. The HMD150 proved to be just what the crew at Horizon Shipbuilding needed for saving time – in this case, days of time.
Completing the job ahead of schedule while delivering another top notch towboat. When asked if Horizon will be using the HMD150 for other jobs around the yard, Oliver says, “Absolutely.”
Horizon Shipbuilding, Inc. 13980 Shell Belt Road Bayou La Batre, AL 36509 251-824-1660, Fax: 251-824-1664, www.horizonshipbuilding.com.
Tooling Concepts & Industrial Supply, 1600 Industrial Park Drive, Mobile, AL 36693, 251-661-7099.