FD TUNING GUIDE
The modern Flying Dutchman at first glance may seem to those new to the class daunting at first, at least in the context of the many sail and rig controls. In fact, once a correct hierarchial and methodical approach is taken to adjust the rig and sails, it is straight forward and easy to understand.
Let’s start by reviewing several key issues regarding the mast and hardware placement. For the purposes of this discussion we will assume that both the spinnaker and genoa halyard sheave boxes are at the highest legal point possible relative to the measurement deck band. While there are many different spar builders and vendors, it is logical that spreader length, span and sweep dimensions are remarkably similar. This is in no small part because the carbon iterations were designed to mimic the bend properties of proven aluminum sections. A good start point for spreader set up is a 762 mm span between the shrouds, 419 mm spreader length and around a 165 mm dimension from the aft side of the spar to a line between the spreader tips. With the Forte you might try a little less sweep angle to help stiffen that section up a bit. The Forte is incrementally more limber than other carbon spars, but very slightly.
With the mast installed in the boat, place a visible mark on the aft side of the mast where as an example the nicropress sleeve on the halyard loop would be when the genoa is hoisted to it’s maximum point. A graduated scale of at least a foot is helpful attached to the mast. Use 25 mm increments going up the scale. This is done so that halyard rake settings can be repeated easily. On North genoas, both the AP and Light genoas have the same luff wire lengths so this works well. The Heavy genoa has a very slightly longer luff wire, based on the premise that this sail would be used typically when the rig is raked, i.e. in heavier air conditions.
When going sailing the amount of rake is a critical first step in determining how much power is available to utilize. In lighter breeze the genoa halyard is raised all the way, bringing the mast as vertical as possible. If the boat has adjustable genoa cars those are all the way up and in. The centerboard pin position is forward and the board all the way down.
At this point let’s remind ourselves that because the FD centerboard is not the most efficient underwater profile, we need to maximize it’s effectiveness by ensuring the board is at maximum thickness (23 mm), and that when it is in the fully down position it is at the maximum depth, which is 1060 mm from the hull to the lowest point.
Under way, we are watching the genoa telltales to ensure they are flowing when the genoa is sheeted in all the way. If they are not some rake may have to be induced or the sheet eased. At the same time the twist of the main is monitored and adjusted via the vang and mainsheet. The objective in lighter air is to have the top tell tale flowing most, but not necessarily all of the time.
As the breeze increases one good guideline in determining the proper rake is when the end of the boom must be eased to or beyond the edge of the cockpit to maintain the boat’s balance. If that boom end is out there most of the time, it’s time to dial in some rake.
When that occurs every other sail control must be adjusted to keep the proper relationship in twist between the sails. Genoa cars start coming down, the boom vang is tensioned, lower shrouds tensioned, etc. As the mast is progressively raked, the centerboard pin position will need to be drawn aft. I have found that the real adjustment range fore and aft on the pin carriage is usually no more than 50 – 70 mm. This is partly because as the wind and boat speed increases to planning conditions, the centerboard will be raised somewhat, usually 125 + mm.
When the rake reaches a certain amount, it will be time to change the genoa leech grommet to which the sheet is attached. Usually for every 125 mm plus of rake change it will mean a leech grommet change. That is a macro change that is fine tuned by the genoa car up and down, and fine tune side of the genoa halyard. Depending on sea state, the genoa car can be adjusted outboard to open up the slot a bit.
The graduation amounts detailed above are meant only as guide lines. The real goal is to develop a feel for what is right in a given condition with available power (rake) and righting moment (the weight and position of the crew).
The crew should, depending on the sea state, adjust their position fore and aft to get the knuckle of the bow just touching the water, especially in planning conditions.