Mast Tuning

[jetboatn]

Recently purchased new rigging for a 95 h26. Standing and running. Tuned standing rigging to the best of my knowledge. Mainsail is pumping pretty bad. Tuned rig with a little aft mast bend but when I tighten the side shrouds it takes the bend back out? Sailed best with wind from the starboard side, very little pumping!!! Owned a 23.5 prior to this boat and it seemed to sail much easier! Any help would be appreciated.
PS. After my last sailing adventure I am really thinking of filling up the jetboat again Thanks

 

[John23883]

Do you have a manual?

If you don't have a manual, go here: http://www.marlow-hunter.com/export/Owners-Manuals/19-23.5-26. Owners Manual....pdf

Scroll down to pages 29 and 30 on the pdf list.

You really need the boat on the trailer to do this. Then you need to put a level on the cabin top and raise or lower the trailer jack for fore and aft level. Then I use an old bottle jack to lift the low side of the trailer for side to side level. This the only way you can be sure the mast is plumb and measure the mast rake. You must do this first. Now comes the time consuming part as if that wasn't enough.

You really need a Loos gauge to measure the tension, for a $100 it's a cheap investment. I was up at Melges in Zenda Wisconsin for something else and asked their expert, he felt about 600 lbs on the uppers was about right. So that's what I do.

I use the 2" of bend specified.

You will need to tighten the upper shrouds to bend the mast, then tighten the lowers to straighten the mast. Then tighten the uppers to put mast bend in. Then tighten the lowers to bring it out. You need to do this to gradually get up to 600 lbs on the uppers and the lowers will be whatever it takes to get the proper 2" mast bend. I think my lowers are about 400 lbs or less.

CAUTION: Do not try to speed this up by putting the 600 or 400 lbs in all at once!

 

[Ray Bowles]

John really has given you a very good bit of info. I had a 95 H26 that I actually leveled with a transit while the boat was on the trailer. I then centered the mast, raked it and then tuned the rigging with a Loos gauge. The 2 inch bend works well and approach the shroud tension settings slowly and uniformally. No more than 2 turns at a time after reaching 200#'s. Keep sighting up the mast sail tract for straightness.
She'll sail with a new level of performance. Now it's time to learn about outhaul adjustment and vang controls.
Ray

 

[Crazy Dave Condon]

to measure the mast correctly side by side, take a long metal tape and raise it using the main halyard. Then go to one side of the boat just forward of the shroud chain plate and then measure in the same spot on the other side of the boat. Then adjust sideways by loosening or tightening the upper shrouds to get the top of the mast in the middle of the boat with the lowers loose of course.

The go and look up the back side of the mast along the sail track and straighten the sail track with the lowers. From there, always tighten in have turns equally for the uppers and of course for the lowers.

What you want with the mast rake backwards, I would have equal adjustments in the forestay and upper shrouds turnbuckles within the turnbuckle bodies. I would then take the main halyard and add some weight so I could see with the mast up of course 4-5 inches of distance from that line to the back of the mast where the boom attaches. Using the lower, I would tighten to bring the mast back. You want some minor bend in the mast.

With the upper shrouds when I could pull inward with two fingers 1-2 inches, that was pretty close and then adjusted the lowers which generally the lowers are tighter. Take the boat out and see if the mast bends sideways and readjust. If you have a little weather helm, that is good. If too much, then move the mast forward.

There is more but this should help.

 

[philwsailz]

to measure the mast correctly side by side, take a long metal tape and raise it using the main halyard. Then go to one side of the boat just forward of the shroud chain plate and then measure in the same spot on the other side of the boat. Then adjust sideways by loosening or tightening the upper shrouds to get the top of the mast in the middle of the boat with the lowers loose of course.

Why not just use the halyard itself? Adjust it to just barely hit one point on the port side, then go to starboard and see if it just barely hits corresponding point. A few trips back and forth and you will get it. No risk of losing a tape to Neptune.

 

[Crazy Dave Condon]

You can use the halyard like I did but many would pull so hard forgetting the fact whether low stretch or not, line does stretch and would give adverse lengths. This is why a long measuring tape but you are correct as long as you put the same pressure on the line when checking side to side measurement.

crazy dave

 

[Jackdaw]

Here my method the combines the two.

Attach your Bosun's chair to your main halyard. and lock it so when you are in it, you are in the air about 4 feet off the deck. This will place an even amount of stretch on the halyard. Mark with tape a spot on the halyard in front of you, and them while on one side, swing over and mark the shroud next to the tape. Then swing over the boom and mark the other shroud in the same place with tape.

Now adjust your turnbuckles/shrouds so the tape marks are the same distance from the top of your chainplates. When that is true, your rig is perfectly straight.

 

[Nom De Guerre]

Here my method the combines the two.

Attach your Bosun's chair to your main halyard. and lock it so when you are in it, you are in the air about 4 feet off the deck. This will place an even amount of stretch on the halyard. Mark with tape a spot on the halyard in front of you, and them while on one side, swing over and mark the shroud next to the tape. Then swing over the boom and mark the other shroud in the same place with tape.

Now adjust your turnbuckles/shrouds so the tape marks are the same distance from the top of your chainplates. When that is true, your rig is perfectly straight.

Holy Mackinac, that sounds like a lot of work for little additional benefit! I use the 'halyard method' and it's always been close enough for the end goal; and we're talking about many times doing this when I had the C22, as well as twice now on the H 28.5.

 

[Jackdaw]

Holy Mackinac, that sounds like a lot of work for little additional benefit! I use the 'halyard method' and it's always been close enough for the end goal; and we're talking about many times doing this when I had the C22, as well as twice now on the H 28.5.

Hmm.

The WHOLE process takes less than 10 minutes.

But once you mark your shrouds with good tape, they will stay marked for years and then the actual measurements (from there to the chainplates) with the steel tape are now 10 times faster.

As for a value of a mast perfectly perpendicular to your deck, I'll let you be the judge of that.

 

[Nom De Guerre]

Hmm.

The WHOLE process takes less than 10 minutes.

But once you mark your shrouds with good tape, they will stay marked for years and then the actual measurements (from there to the chainplates) with the steel tape are now 10 times faster.

As for a value of a mast perfectly perpendicular to your deck, I'll let you be the judge of that.

Lol, it takes me ten minutes to FIND the bosun's chair.

Ok, so maybe I've tilted at windmills. But really, you think your method (swinging on the line in a chair) is that much more accurate than applying similar pull to the line on both sides? And even if it were, you really think that your deck is perfectly perpendicular to your hull, and your hull is perfectly perpendicular to your keel?

I see the same value you do, but the law of diminishing returns and similar margins of error using either method applies here...

 

[Jackdaw]

Lol, it takes me ten minutes to FIND the bosun's chair.

Ok, so maybe I've tilted at windmills. But really, you think your method (swinging on the line in a chair) is that much more accurate than applying similar pull to the line on both sides? And even if it were, you really think that your deck is perfectly perpendicular to your hull, and your hull is perfectly perpendicular to your keel?

I see the same value you do, but the law of diminishing returns and similar margins of error using either method applies here...

all good!

Its actually pretty hard to get the same amount of stretch out of 70 feet of halyard after its been up and down the mast, and around at least 1 or two blocks. If you don't, its going to be off an inch or so, and then you might as well eyeball it!

Watch a pro rigger. Most do it this way.

Of course your keel is another matter. And even if your deck/hull is is a bit off, what you at least get here is repeat-ability. The boat works the same way every time. That's 90% of the battle!

As to where your bosun's chair is, I can be of no help! ;^)

 

[isaksp00]

You can buy a pretty long tape from Harbor Freight at fairly low cost (I think around $5 or 6 on sale), much less than the $25 or so at the big box stores. Cheap enough to keep on the boat. I shackle the end (it has a plastic loop) to the halyard, along with a light line as a "safety" should the tape break (which has never happened). It is easy to measure to some landmark, like the top edge of the chainplates. I have found that the tape does not stretch much; you can pull it fairly taut. Whatever stretch may actually occur that is different on each side would have to be trivial.

 

[Nom De Guerre]

all good!

Its actually pretty hard to get the same amount of stretch out of 70 feet of halyard after its been up and down the mast, and around at least 1 or two blocks. If you don't, its going to be off an inch or so, and then you might as well eyeball it!

Watch a pro rigger. Most do it this way.

Of course your keel is another matter. And even if your deck/hull is is a bit off, what you at least get here is repeat-ability. The boat works the same way every time. That's 90% of the battle!

As to where your bosun's chair is, I can be of no help! ;^)

I guess the theory being that lots of pull (say 200 lbs, no offense, just guessing ) is going to more accurately stretch the line evenly for both sides.

I'm picking up what you're laying down (I just like euphemisms, I'm also happy to say it sounds like you're right and I'm wrong on this count - but notice I've bracketed it at the end where fewer readers are as likely to notice).

Now, to consider the 50' tape idea.