During a year long design period of an 86 foot carbon catamaran one inherently finds oneself dealing with perhaps the holiest of the trilogy of performance cat construction: weight. This is an interesting project as we have been allowed to go to absolute detail to then be able to guarantee a sail-away weight directly from the plans.
This hasn’t been finger in the air stuff either, we’ve really got down to detail. Obviously finite analysis has provided exact amounts of carbon and resin needed but that’s not really ground-breaking. Mast makers and sail makers can be very exact these days as well. Of course we know the weight of the engines, the length and weight of associated cable and piping for those engines, we even have a weight for the tools, spares, oils, filters, impellers needed for the first months of cruising with those engines. We know the weight cost per BTU for bringing the salon down to 19 degrees in the tropics. We’ve shuddered at the weight of the glass, yet been astounded at the weight of the Pre-Fossilised oak flooring. Paper charts to courtesy flags, soup bowls to bread knives, it’s all been taken into account. We’re even testing whisky from very light, finely-turned aged oak tumblers crafted by our materials consultant. (We’d like to say they are very good but that would mean no more testing…)
Now to the paint. Surely paint isn’t that heavy we thought? Well, we learned that the chosen paint and process would come in at 3.37kg psm. We did a little mental calculation. This needed more investigation.
Even though we will use carbon moulds we know that there will still be a need for some fairing. Then a surfacing filler will be applied, then high build primer, then primer and after all this finally we see the top coat. However, at every stage there will be a lot of very exact sanding performed. Digging deep into the process we learned that actually 10% of the fairing will be removed, 30% of surfacing filler, 30% of the high build, 50% of the primer and 30% of the top coat. With all this having been done, we find our paint weight is actually 2.7kg psm. In whole boat terms the overall difference is the weight of the proposed tender. We can add quality control by creating a sanitary environment and use the aeronautical technique of weighing the vacuums once the sanded product is removed from the paint area.
Our next project is to analyse the results of our ongoing antifouling tests. At 4.18kg psm for a respected industry standard paint we think that there is a lot of work to be done here.
