{"id":17380,"date":"2011-09-09T12:54:23","date_gmt":"2011-09-09T17:54:23","guid":{"rendered":"https:\/\/setsail.com\/?p=17380"},"modified":"2018-04-09T11:43:14","modified_gmt":"2018-04-09T16:43:14","slug":"fpb-64-vs-reef-are-the-factors-of-safety-sufficient","status":"publish","type":"post","link":"https:\/\/setsail.com\/fpb-64-vs-reef-are-the-factors-of-safety-sufficient\/","title":{"rendered":"FPB 64 Vs Reef – Are The Factors Of Safety Sufficient?"},"content":{"rendered":"

“Having a boat that can deal with whatever might happen\u2014no matter what\u2014provides a mental comfort level that defines their view of happy sailing.”<\/em>
\n–Bill Parlatore, Passagemaker Magazine<\/em><\/p>\n

\"Iron<\/p>\n

The various rules to which yachts are built are based on seagoing loads. If you design to ABS or Lloyd’s, odds are you will be OK \u00a0offshore, but there is little extra margin for the mistakes which are a part \u00a0of cruising. With an ABS keel structure, if you go aground, it is almost certain a trip to the boat yard is in your immediate future. But if you engineer to four<\/span> times<\/span> ABS, you are probably going to continue with your cruising.<\/p>\n

We have tested these these theories ourselves, and had our owners repeatedly test them on our sailing designs. Now we have some real world verification of the FPB 64’s factors of safety.<\/p>\n

The photos which follow were taken of one of the FPB 64s\u00a0after it tangled with a reef in the Fiji Islands. She has been hauled to replace a damaged stabilizer fin. At the end of this post is a link to the details of the event which has some excellent lessons for us all.<\/p>\n

<\/p>\n

Pete Rossin, Iron Lady’s<\/em> skipper, told us “We dragged along the reef for close to 2 hours although more\u00a0intermittently as time went on. The first hour was horrible.\u00a0Tide was coming in – we hit the reef about an hour or so after low.\u00a0My analysis is that we JUST clipped the outer reef edge with the bow\u00a0on the stbd side as we were trying to exit to deeper water – another\u00a0few meters off to to port and we would have been fine. \u00a0The wind then\u00a0blew us around on to the outer side of the reef and pinned us but also\u00a0blew us along the reef. \u00a0There were deeper stretches in between the\u00a0heads and that is why we drifted and bumped slowly along the reef\u00a0until we made deeper water…”<\/p>\n

 <\/p>\n

\"Iron<\/p>\n

There is superficial paint damage forward which coincides with a water depth of about 3.5′ (1.05m). The damage is mainly in this area and \u00a0all the way aft, indicating coral head tops with deeper water between.<\/p>\n

\"Iron<\/p>\n

This is the leading edge of the prop skeg, here about the same depth as the forward abraided paint area.<\/p>\n

\"Iron<\/p>\n

The abrasion on rudder tip and skeg bottom show the same water depth as is found forward.<\/p>\n

\"Iron<\/p>\n

The rudder probably cut into the coral on impact. We have used a factor of twice ABS on our rudders for many years. This is an indicator twice ABS is on target.<\/p>\n

\"Iron<\/p>\n

The fact that the prop coating is mainly intact tells us the skeg\u00a0is doing its job.<\/p>\n

Several factors helped to mitigate the damage incurred and the time spent on the reef:<\/p>\n