72 Cheoy Lee RHP Motoryacht info

Most premium boat builders use cored hulls. My personal preference is a solid glass hull beneath the waterline, but cored hulls save weight, which equates to better performance and reduced fuel costs. My concern about foam cores stems from impact. The compression of an impact can weaken foam cells, which can be exasperated by water pressure constantly pounding the impacted area, further breaking down cell walls and ultimately causing the skin to delaminate from the foam. If the skin is breached, then hydraulic erosion of the foam can become catastrophic; a worst case scenario.

While cored hulls are certainly strong, in some ways they are more fragile than solid glass because you are merging different materials. The bonding of foam to a fiberglass skin isn't chemical in nature, but rather adhesive and the best way to accomplish this is resin infusion, something that most boat builders didn't adapt until recent years.

No matter how well you saturate a laminate, the possibility of delamination remains constant, whereas a solid glass laminate is highly unlikely to separate, even after impact. When a cored hull is subjected to impact, you may not see external damage but there's a probability the core has been damaged, which can weaken the cell walls. Once your core structure is compromised, it is prone to further deterioration.

If the skin is breached and water penetrates the core, in theory it is suppose to remain isolated in a closed-cell foam environment, however water has a way of seeking channels. With cores such as Divinicell, the kerfs that allow the foam to conform to compound curves leave open channels where water could conceivably flow. Even if water enters at a remote location, in time it can travel throughout a core. This is why resin infusion and vacuum bagging has become so important in the layup process. It is the most effective method of ensuring complete saturation, specifically between the kerfs.

I just invited Panu Virtanen, the VP of Cheoy Lee North America to join in this thread. I'm sure he can answer any questions you have about their boats, past and present.

Thanks Carl. This is Panu at Cheoy Lee Yachts. This particular Fexas design is solid skin hull below the waterline so the topic really is not relevant. If you come across another Cheoy Lee, one with cored hull there should be no concern because the coring used is closed cell foam not absorbing water. All Cheoy Lee hulls are designed by qualified composite engineers based on Classification Society rules. Resin infusion and vacuum bagging takes away any concerns as Carl mentions above. Cheoy Lee is one of the early adapters of the resin infusion method and one of the more experienced builders in that field. You can PM me for more info on the Fexas 65/72 design.

This is a reminder too that when asking questions about older and specific boats, the builder is really the place to go. They do have the information and can give you accurate information. Everyone else is "almost", talking about boats similar or close in size and age or another boat they saw, but can't promise accuracy on a specific boat.

Especially when the builder representative clears up the issue in question and does so without launching into a major advertising effort. I felt Panu handled it well.