Photo By Oscar Pope | Mid-Atlantic Regional Maintenance Center (MARMC) Zone Manager, Jeffrey Wunsch, poses...... read more read more
Day-to-day operations aboard Navy vessels is sure to bring wear and tear to many shipboard components, and the J-bar davit is no exception. Typically positioned on the starboard side amidships, the J-bar davit is a device, used to launch and recover small boats and other equipment.
During a single deployment, the J-bar davit can be used more than 50 times, causing significant wear and tear on its bearings. As parts of the davit degrade, the integrity of the davit is also compromised, safety issues ensue, leaving the Navy with expensive repairs.
“Normally, we would replace the existing bearings very often due to swelling caused by water intrusion,” explained Mid-Atlantic Regional Maintenance Center (MARMC) Zone Manager, Jeffrey Wunsch. "This swelling, caused by the bearing material absorbing water, prevented the J-bar from fitting properly into its coupling."
To combat this issue, Wunsch and his team spent several months working with Canyon Marine Solutions and Building LF-18’s Engineering Department, to get necessary process and material measurements.
“We started using a new material called Thermoplastic Blue to manufacture the bearings,” said Wunsch. “This thermoplastic is much more resilient to the weather conditions.”
Thermoplastics are polymers that can be softened through heating before being processed and then left to cool and harden. Once cooled, they show no changes in chemical properties, meaning they can be re-melted and re-used several times.
“We believe this is going to be a great cost savings to the Navy and allow ships to better maintain their J-bars alleviating frequent replacement,” added Wunsch.
The new thermoplastic bearings are expected to last years, vice months compared to the old phenolic bearings. Due to the thermoplastic’s extremely long life span, cost savings will occur over time as the price for the new material is the same as the old phenolic material.
The Navy’s first successful installation of the thermoplastic bearings occurred in April 2024 aboard USS Oak Hill (LSD-51), a Harpers Ferry-class dock landing ship.
MARMC, a field activity under Naval Sea Systems Command (NAVSEA), provides surface ship maintenance, management and oversight of private sector maintenance and fleet technical assistance to ships in the Mid-Atlantic region of the United States.
| Date Taken: | 05.20.2024 |
| Date Posted: | 05.21.2024 09:38 |
| Story ID: | 471717 |
| Location: | NORFOLK, VIRGINIA, US |
| Web Views: | 113 |
| Downloads: | 0 |
This work, Thermoplastic Bearing Upgrades to J-bar Davit, by Oscar Pope, identified by DVIDS, must comply with the restrictions shown on https://www.dvidshub.net/about/copyright.
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