Questions about mast rake

Hey guys,

So I've been getting more and more into tuning up my late 70's Hobie for better speed, and I've begun to delve into mast rake. However, I have lots of questions pertaining to this that hopefully you guys can help me out with.

First off, I see lots of people mentioning needing a longer forestay for more rake. However, I was under the impression that the jib halyard is what tensioned the mast and the forestay is usually way longer than it needs to be and just sits slack. Is this not the case for most people?

Also, I'm having trouble visuallizing the correct amount of rake on these boats. Can someone put it to me in terms of degrees, 90 being straight vertical and 0 being sitting on the tramp? The measuring convention doesn't make sense to me. How far is the boom from the tramp at the stern? On my boat it's at least a foot I'd say.

Thanks a lot, and feel free to correct anything I've said, as I'm still relatively new to sailing Hobies.


Thanks,
Dustin

When you adjust your shrouds to the lower part of the stay adjusters it makes the forestay not reach the standard bridle chainplate, hence the addition of the second plate. You are correct that the jib tensions the rig and that would be attached on the lower (primary chainplate) and rake is adjusted depending on where you place the foot of the jib on the plate. Tuning will depend on your weight, wind, water conditions etc so you need to trial and error it as much as possible to find the right combination for you and your boat

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1985 Prindle 16

There are a lot of considerations when raking the mast back on a 70's boat.

Lots of parts have been changed ever-so-slightly over the last 40 years to tweak every fraction of an inch increase in mast rake. 1 tweak isn't that much. Collectively, they add up to a lot.

The way I would start is to rig the boat, main up, sheets attached, jib halyard fairly loose - just take the tension off the forestay. Put enough downhaul on to remove the wrinkles in the front of the main.

Sheet the main in until there's only about 4" between the blocks and cleat it. Doesn't matter whether you have the old Seaway blocks or a low-profile setup.

Now tighten the jib halyard as hard as you can. If your shrouds go tight before the mainsheet, move the shrouds up in the adjuster a hole or two. That's your maximum mast rake setting for most conditions.

One of your shrouds is probably loose. Guess at how many holes you'd have to go down in the adjusters to take most of the slack out and adjust as necessary.

The goal is to have the mainsheet go tight before the shrouds, but not that much more.

Make sure the mast can rotate cleanly, without interfering with the step or the step link. Remove the link if you need to.

Now sheet the jib in. Adjust the height of the tack on the forestay adjuster until there's about 2" between the blocks when the sheet is snug, but not really tight. Remember what hole it's in for future reference. If you've got the 5 hole clew plate, you'll need to move the sheet attachment down as the tack goes up - but it's not hole-for-hole.

If you've got the stock jib halyard, mark the location of the upper block on the mast (Sharpie or electrical tape). If you've got an Aussie halyard, mark the line at the black band on the mast. Now you've got a reference point as long as the jib tack is in the the same hole.

You can see very quickly that the easiest way to increase mast rake is to reduce the sheet stack-up on the main and jib, especially the main. Going to a low profile main system is the fastest way to increase your mast rake. However, by taking a giant leap, you uncover other problems - the jib can't be sheeted in all the way, the mast base/step don't fit well together, etc.

Now go sailing and see how bad your helm is. Them come back and we'll tell you how to fix it. A well-behaved 16 has almost no helm going upwind.

Wow, thanks MBounds. I've been looking for a concise "to-do" on how to progress through the set up. The only other thing I found was a way to "measure" mast rake by taking the main halyard to the bows, holding where it touched the bridle screw, and then walking it back to the stern to see what the difference is. Not at all scientific or precise, but a way to at least see some of the affect of making all the changes. I like your method better because it's actually, well, a method!

_________________
'81 H16

If it ain't a blowin', I ain't a goin'