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EXAMPLES OF POOR PRODUCTION PRACTICES
Some examples of poor production planning, poor production management and poor quality control:
A well known and highly respected manufacturer of offshore sport fishing boats produced a 26 foot center console boat which was very popular. From customer feedback they determined that the one thing they could do to make this boat better was to make it 2 feet longer. So they did. This model was snatched up by fisherman.
Soon, problems began to crop up. Stress cracks began appearing in the hulls at the transom and several feet forward of the transom. Hulls began separating from the inner liner. The bolts holding the center console in place came out. Some owners reported that the hulls flexed so much in a seaway that they couldn't use the boat.
The concept was sound and is a frequent practice in the boating industry. So where did they make their mistake?
First; they didn't do any extensive engineering analysis of the stresses that would occur by putting the outboard engines two feet farther aft. Two hundred horsepower engines are heavy and in addition to the weight, have a two foot longer lever arm. They did not increase the strength of the structure or add any additional supporting members. They did not increase the thickness of the hull or change the laminate lay up schedule. A Finite Element Analysis and a structural analysis should have been done on the planned model. With computer software almost any engineering firm can do this.
Second; they did not do any in use testing of the final product.
Third; when customers complained the remedies given were purely cosmetic. They did not fix the problem and in many of the boats it reoccurred.
Eventually they were forced by the Coast Guard to recall all of that model line, over 200 boats. Many of the boats had to be replaced with a new boat. It was a financial disaster and ruinous to their reputation.
It was a complete failure of production planning and quality control to prevent the problems with this boat.
Whenever a significant change in the design of a boat is made the design should be completely re-evaluated and a structural and hydrostatics analysis done. Hire a naval architect or engineer to do an analysis and make recommendations. Significant changes can result in a decrease in stability, structural strength and less load capacity. If this is a larger boat you may even need to do a stability test. See the Ethan Allen case. http://en.wikipedia.org/wiki/Ethan_Allen_Boating_Accident
A well known manufacturer of aluminum utility boats and jon boats had a factory in a northern mid-western state where the winters are extremely cold. They used two part spray foam as flotation material in the boats. The chemicals were stored in drums in an unheated area. As needed the drums were brought into the factory and used up. A boat, tested by the US Coast Guard for level flotation, failed the test. In fact it sank, indicating it had no flotation at all. Upon examination it turned out that in the compartments where there should have been foam was a pile of what looked like a cow pie, or bread dough. It was foam that simply hadn't foamed.
The manufacturer determined that about 1200 boats had this problem. They had to recall all of the boats to the factory, remove the bad foam and put in new. Obviously this was costly because not only did they have to redo the work, they also had to pay for transportation of the boats to and from the factory.
Here was a clear failure of production planning and quality control.
They did not take into account the temperature of the chemicals when they were used. The manufacturer of the foam specifies a narrow range of temperatures and the foam had been stored in an area where it was sub freezing and then used while it was still cold. When combined, a chemical reaction simply did not take place. The production plan should have specified that it be brought in early enough to warm up and the temperature checked before use, or stored in a heated area.
If a small sample had been blown into a test box or container before using it in the boat then the person doing this would have realized something was wrong. A test sample should always be made at the beginning of each days production, and especially on a new batch of materials.
On these boats, once the foam was blown in, the compartment was immediately covered and there was no way to check to see if the foam actually foamed up. The production plan should have specified a way to check this. For instance, simply waiting a few minutes before covering the compartment would have given at least a visual check. Occasionally a boat should have been taken off the production line and put in a test tank and given a level flotation test.
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