Question: I’ve recently had my boat repowered with a new Yanmar diesel. One of the things I noticed as soon as I got my boat back from the shop was the use of nylon tie-wraps to hold some of the hoses and plumbing in place on the engine (see photo). I have always thought that the use of these nylon ties was a bad idea on engines because the nylon gets brittle and eventually breaks due to the heat in the engine room. What’s your take on this?
Answer: I’m with you. Your gut feeling on this is actually supported by some of the dialogue found within ABYC standards as they apply to wire runs and cabling in engine room spaces. Basically what the Standard says is that any cable runs over moving machinery need to be secured by metal clamps or clips.
In the photo you sent in, the hoses are actually sitting on the engine, so it doesn’t really illustrate that specific point or potential problem, but the potential trouble does exist in the long run. It’s true, the nylon tie-wraps shown will eventually heat-harden, become quite brittle, and break due the extreme heat they are surely going to be exposed to sitting on top of that engine. Without a doubt, rubber coated metal clips are the best choice for this type of service. Just do a quick web search for metal "P-clamps" and you’ll find lots of sources for the type of clamp preferred for this installation.