Mast Rake
Del,I race a Hunter Legend 35 with a fractional rig that is the same as the HL 37.When you change the length of the forestay you are changing mast rake.Rake is not adjusted by the backstay. That is called prebend.Before you change the rake you need to do a lot of measuring.First, with the side stays in proper tension measure the distance aft that the main haylard, when hanging streight down, makes with the boom. This need be done on a no wind day with a heavy weight on the end of the haylard to keep it stay. According to Hunter factory folks my rake haylard distance is 10 inches measured on the boom aft of the mast. My mast is exactly 50'long (high) above the cabin top. Yours may be a bit longer. 10 inches may be your number also.A call to the Hunter rigging shop may produce your rake haylard distance. You need to press them for a number. They are slow to come up with the answeres.If you decide to change the rake you need to loosen the headstay, re-rig the side stays aft with an equal number of turns on the turnbuckels and then let out (that is retighten) the headstay - recheck side stay tension and the rake haylard distance and see if you have increased the rake distance on the boom an inch or two. This is a tricky re-rig procedure as it will also require a few test sails to make sure the mast is true ie. does not lean in one direction or the other.You need be keenly aware of the mast movement in the mast shoe at the foot of the mast. You do not want to lean the mast back so that it is tilted in the shoe and thus put a high structural load on the back side of the shoe.Mast rake is an important factor. If you have too much you will develop a lot of weather helm. Some boats need a lot of rake eg. Hobie 16.I control weather helm by keeping a close tab on travel position. If I am going to weather and the helm is heavy, then I call for my main sheet crew to let the traveler down towards the lee side of the track.I try and keep the boom over center on a point, which puts the travel to weather. Sometimes too far to weather.Weather helm is also controled by the headsail. Jib car position is important. Double check as to why you are using the slot you've selected. The proper position is where all three teltales on the headsail lift at the same time. You do have the three teltales on your headsail ??As I stated above, changing the rake requires a lot of pre planning. Make sure you know where you are now and how to get back to that setting after you have changed it.As to the prebend and the backstay adjuster, that is another issue unto itself.A fractional rig is a lot different than a mast head rig. If fractional is good enough for the America's Cup than it is great for us Hunter guys.Sail on,Bob DeanPensacola, FL