Mast Hound Location and Figuring Rigging

[DNewbie]

Hey all,
A couple of/ lot more questions, if you can stand them. I'm installing an external hound, the type with one horizontal strap and one diagonal strap, on a wooden mast. I'm a little unsure of the location and should add that I don't yet have shrouds. Rule H-13 states that the minimum distance from the base to the pivot bolt shall not be less than 127 1/2". I'm also installing a U-strap on the hound and the U-strap has two bolt locations. Which one is the pivot bolt? The higher or lower one? Also, how critical is hound location? The common wisdom seems to say the lower the better but can anyone suggest a location? How much leeway is provided by the adjusters?

Once I get the hound installed I then have the sticky problem of determining shroud lengths from scratch. I've looked at the Collected Wisdom but the advice there seems to be oriented to adjusting the lengths of existing  rigging. I figure I'm going to stand the mast up using bailing wire and then measure from tang hole to triangle. What I need to know is baseline locations for the mast, plank and boom. Here's some of my hardware specs, if if helps. I've got an adjustable mast step, a Staymaster for the nose tang, Goodwin hull, rear blocks are Harken 57MM. Which position should the mast step be in? Should I flex the plank by adding weight to the hull? If so how much? How close should the rear blocks come to each other without without any sheet pressure?

Oy, this DNewbie, always mit der qvestions, such a noodge....

[Bob Rast DN1313]

You probably want to set hound minimum .Then if you go to glass mast the shrouds will still work.
A lot of sailers are using Ron Sherrys set up which you can find on his web site under tuning, I use 136' side stays  pin to pin with a short tube for adjustment  (Stay is !33"}front stay around 144" with a staymaster for adjustment.

[Geoff Sobering]

How close should the rear blocks come to each other without without any sheet pressure?

Ron Sherry's tuning guide has a wealth of tips and measurements.  Many depend on his hull geometry (which I believe is identical to the Goodwin plans) and mast-bend characteristics, but they're still good starting points.

Specifically, to answer you question about boom-deck height, Ron recommends '14" to 16" between the boom and the back deck', which seems right for almost any bendy mast.

For a quick check on mast rake, Jane Pegel told me (years ago) to place the mast tip at the center of the plank (easy to do with a weight attached to the halyard).  I still do this when I'm setting a new boat up for the first time and just want to get the forestay length "close".

Cheers,

Geoff S.

[DN 805]

Here's from the chairman of the Tech Comm:  If you're using the external hound, the measurement point is the bolt that attaches the U strap to the hound straps, measuring from the bottom of the socket cup at the base of the mast.   Then go 1/2" higher just to make sure you're legal.

As for stay lengths with the Goodwin style hull, here are Ron Sherry's lengths: using the Sarns triangle -
forestay 144.75 inches, wire fork to fork plus the stamaster.
sidestays 136" fork at top to side stay tang.  If your using an adjuster of any kind on the side stays, then deduct appropriately.  For examble the tay would be 131.75" if you're using a small stamaster on the side stays.

....DN 805

[Bob Gray]

      A good starting point for setting your mast up,  no matter where your mast step is located, is to try and get a mast rake of 69-71 degrees. You can use an inexpensive pendulum protractor available at most hardware stores to do this. This rake will most likely give you adequate boom to deck clearance. Just about every boat is different. The length of the nose forward of the steering post can vary, where the mast step plate is located, plank stiffness, mast stiffness,etc., etc., etc.. I agree with a 147-148"  total headstay length ( with the staymaster set in the middle). I do have a problem with the ever popular 136" sidestay length. I carry my mast more foreward the most and need 138" +  long side stays. What I strongly recommend is that have your sidestays made up with a pair of those 6", ten hole, pin adjustable fixtures at the ends. With the adjustment set in the middle, have them made up to 136". This will give you a fair amount of latitude if you have to move your mast around.
                                                                                    Bob

[DNewbie]

Thanks for all the thoughtful replies. These definitely help with the cause and provide different ways for thinking about the same problem. I was wondering if anyone can help me narrow it down.

I've got a sliding mast step with around a 5" range, forward position starts at 35 1/2" aft of the chock post.
Center line of runner axis on the fuselage plates starts at 97.25" aft of chock post and goes back about 5 1/2".
Plank crown is 2 1/2" with a deflection of 2".
Halyard has 6" of adjustment, in 1 1/2" increments.
Nose tang is forward of the chock post by 6".
This is a Goodwin hull with a overall length of 144".

So, when measuring for the shrouds:

1) What position should the mast step be in?
2) What position should the plank be in?
3) Should the plank be weighted or unweighted with skipper's weight?
4) What position should the sail be in?

Any specifics here would really help out.

[Geoff Sobering]

Halyard has 6" of adjustment, in 1 1/2" increments.

1 1/2" is a bit large for halyard length adjustment.  Typically, people will mount two catches on the front of the mast, spaced half the distance between balls on the halyard.  With that setup you would have 3/4" adjustments, which is much better.

One way to help figure out stay lengths is to borrow a set and use them to rig your boat on dry land.  You can use line or other temporary assemblies to temporarily lengthen, or even replace, a stay while you try the combinations of mast-step, plank, and halyard location to make sure things work out.  Then measure the temporary stays and make a permanent set with the adjustment ranges you found during the trial.  If you have a non-standard mast, it may take making a set of stays and sailing with them in some different conditions to get a final set of lengths that allow you to get the behavior you want. 

With my "strange" masts, I've always made an inexpensive set of stays using Nicopress eye-loops and scrap cable to make sure I got the right lengths.

Cheers,

Geoff S.

[Bob Gray]

    These are rough settings and so even if you don't have fiberglass mast now, you probably will soon so here goes:
1). You probably want the mast step ball about 39" aft. Here's a rough way to start.  Set the mast up so that it's at a rake of 69-71 degrees. Take a tape measure and hook the dumb end on the headstay , keeping it at a 90 degree angle, measure the distance to the center of the mast step ball. A good starting point is 34".

2). Assuming you have the 4 hole Sarns alternate plates, use the second hole from the back for mounting the plank.

3). Weight the plank with your weight plus 30 lbs.

4). Set the sail down about 4".

[DNewbie]

Thanks guys, this is just the information I was looking for. Now that I'm armed with this knowledge I feel confident I can come up with an accurate measure and get my boat on the ice.