Sanity check before I tune my rig...

Sep 13, 2015
19
Catalina 22 Eugene
So I've got a new to me 1989 Newport 33. I've got Brion Toss' tuning explanation DVDs which I've watched and part of what I'm using as a starting point is his mention of bringing the lowers to 10-12% of load rating and uppers to 15-20% of their rating. He explains why based on stretch and length and all and this all makes perfect sense.

The boat as I received it has the rig set fairly loose compared to these figures. I also have a survey from a while back that states that the rig was "not properly tuned".

I will say that the mast is in column well. I also have measured that the step is in good position on the vessel.

So based on this I've got 7/32" wire. Which I understand to have a breaking load of about 5445 lbs.

So I then figure I want to be in these ranges:

Lowers@10% = 545 lbs
Lowers@12% = 653 lbs

Uppers@15% = 816 lbs
Uppers@20% = 1089 lbs

That translates to a PT-2 Loos gauge setting of 26 for the lowers and 30 for the uppers.

When I measured what they are currently set to I get 24/17 port and 22/16 starboard. So in order to get to the settings recommended I need to add a little over or under 400 pounds to each wire. This is a deck stepped mast with a wooden compression post in the cabin. I just want to verify that this seems like a reasonable starting point for me to shoot for and to then finish the tune while underway.

Thanks much

~Brett
 
Oct 19, 2017
7,020
O'Day 19 Littleton, NH
Your mast is in column, yet you measure different tensions port and starboard. Have you sighted up the mast to be sure it is straight? How did you determine it was in column? On the hard or in the water? With halyard stretched to each chainplate or hanging a weight to measure plumb to the gooseneck?
Attach the halyard at the gooseneck and tighten to use as a sight guide when sighting up the mast. Any bending will be easier to spot against the halyard.
I can't say whether 2400 additional pounds will have an adverse effect on your boat, but check the specs for your rig. If this boat was customized for an ocean crossing, heavier wire might have been installed. Using the standards for lighter wire, based on breaking strength, may be inappropriate. If she looks good and feels taught, take her sailing and watch the leeward turnbuckles. Tighten as needed, but make equal changes to both sides.

-Will (Dragonfly)
 
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Mar 29, 2017
575
Hunter 30t 9805 littlecreek
What kind of wind region do you sail in if usually light [like a lake] you want to be in the lighter end of that spectrum. If u plan alot of off shore heavy air sailing then tighten it up. Also start by loosening whole rig little by little and watch column. Shake chain plates . Its amazing you can loosen mast to like 6" of play and it doesn't fall over with only 1/2" of deck step holding it but I believe yours is keel step so should be even stronger.
 

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Jan 11, 2014
7,980
Sabre 362 113 Fair Haven, NY
That translates to a PT-2 Loos gauge setting of 26 for the lowers and 30 for the uppers.

When I measured what they are currently set to I get 24/17 port and 22/16 starboard. So in order to get to the settings recommended I need to add a little over or under 400 pounds to each wire. This is a deck stepped mast with a wooden compression post in the cabin. I just want to verify that this seems like a reasonable starting point for me to shoot for and to then finish the tune while underway.
Those numbers sound about right based on what I remember from my Sabre 30.

However, simply bringing the shrouds up to the proper tension is only part of the process. The mast needs to be in column, i.e., straight up. It also will need to have some prebend and perhaps some rake. Rather just starting from where you are now, loosen all of the shrouds and stays to just less than hand tight and shake the rig. This will loosen everything up and undo any errors. If there is a bend in the mast, you will never be able to straighten it unless you go back to the beginning.

The first step is getting the masthead centered over the boat and in column. Do this with a measuring tape and sight by eye. Once it is centered begin bringing the shrouds up to the proper tension by making small adjustments equally on both sides until the desired tension is achieved, two turns on port, two turns on starboard. You'll make a lot trips back and forth. After a while you will get a feel for how many turns you can take at one time. Go slow at first.

Selden Mast has a good tuning guide: https://www.seldenmast.com/files/1571039872/595-540-E.pdf

US Spars has another guide: https://www.usspars.com/wp-content/uploads/2011/03/rigging.pdf

Take your time, don't be afraid to go back and start over. Tuning is both a skill and an art.
 
Oct 26, 2008
5,047
Catalina 320 Barnegat, NJ
I use the PT-2 Loos gauge for tuning my rig with 7/32 shrouds as well. Last year I found that the yard leaves the shrouds too loose, while I was charged for "rigging". You've got the correct figures & right idea for tuning. Like Dave says, take your time and tighten a little at a time on both sides. When you tighten one side, you are increasing tension on the opposing side as well. For various reasons, you won't always have a direct correlation, as you already found. But you don't want to pull the rig out of line by making a single large increase on the first side that you adjust.

I'm curious about the forestay tension and the backstay tension. It seems like it will be tricky considering I can't get the Loos gauge over the furling foil for the forestay. Also, it's not so easy to get access to the back stay above the split. Any good ideas? I haven't read thru those guides yet, and hopefully there is some explanation. I've checked the rake of the mast, which appears to be reasonable at about 6 inches, which would be about 1 degree. What I would like to do is verify backstay and forestay tensions at various degrees of adjustment on the backstay tensioner.
 
Oct 22, 2014
16,409
CAL 35 Cruiser moored EVERETT WA
Scott, unlike the Shrouds on the side of your boat which center the mast and keep it in column, the fore and back stays are meant to be adjusted. It would be pointless to adjust the tension as when you change your tack it would need readjustment.

Tension up wind, loose down wind is the basic adjustment. When I leave the boat, I loosen the back stay tension to reduce the downward forces on the base of the mast. When I board, I snug it up so the forestay does not sag. This makes raising the fore sail on the furler easier. When tacking upwind I increase the forestay/backstay tension.
 

DArcy

.
Feb 11, 2017
1,303
Islander Freeport 36 Ottawa
First, congratulations on the new boat! I tried to find a PH version when I was shopping for a boat but never did find a suitable one.
20% is a good number for the uppers but your numbers for the lowers seem a bit low. 12% for the lower might be good for a starting point but you may find the leeward shroud becomes loose with moderate wind. Try 20% for the uppers and 12% for the lowers then go for a sail. In 10 to 15 knots of wind with full sail, sailing up wind, check the mast to see if it is still in column by sighting along the mast track. If you are comfortable with what you see then you are ok, but if the middle of the mast sags to leeward then tighten the lowers. if the top of the mast sags to leeward then you may need to tighten the uppers (or loosen the lowers).
 
Oct 26, 2008
5,047
Catalina 320 Barnegat, NJ
Scott, unlike the Shrouds on the side of your boat which center the mast and keep it in column, the fore and back stays are meant to be adjusted. It would be pointless to adjust the tension as when you change your tack it would need readjustment.

Tension up wind, loose down wind is the basic adjustment. When I leave the boat, I loosen the back stay tension to reduce the downward forces on the base of the mast. When I board, I snug it up so the forestay does not sag. This makes raising the fore sail on the furler easier. When tacking upwind I increase the forestay/backstay tension.
I understand your point. Basically the objective is to set the rake with the forestay, then tension the backstay. I guess I am questioning what tension would be a starting point. I'm thinking that 15% of load rating on the forestay would be the starting point for correct sag in light wind (or downwind sailing). Obviously, I use the backstay adjustment to take out sag as the wind increases for upwind sailing. Basically, with even a moderate wind of say 8 to 10 knots I'm adding some tension with the backstay. I'm looking for a possible way to quantify tension so that I know optimal tension and corresponding backstay adjustment for the wind conditions. My current method is to simply add tension so that the helm feels right. I don't even think that I can trust my observations of forestay sag while sailing. I think I'd be surprised at how inaccurate my observations would be. I'd like to figure out a way to mark my backstay adjustments so that I have optimal positions as the wind increases or decreases. I wonder if that makes any sense! :what: What it comes down to, I think, is that I don't trust my observations of the forestay to be able to determine when I get the sag right. I get better feedback from the feel of the helm. I know that adding tension during wind increases is helpful when I feel the helm get "lighter" - more responsive to adjustment - but I'd like to have a better understanding if my senses are "correct" from a quantitative aspect. That's the engineer in me.
 

dLj

.
Mar 23, 2017
1,889
Belliure 41 Now on the Chesapeake
My current method is to simply add tension so that the helm feels right. <snipe> I get better feedback from the feel of the helm. I know that adding tension during wind increases is helpful when I feel the helm get "lighter" - more responsive to adjustment -
This is the the best way to do it in my opinion. If you want numbers, then have an accurate way of measuring you speed and tweek for speed. I don't know of a better method.

dj
 
Oct 22, 2014
16,409
CAL 35 Cruiser moored EVERETT WA
If I was a Brain Doctor, I’d suggest that when sailing you need to use more right brain than left brain.

On my boat, the rigger and I set the forestay so that the mast was 2 degrees raked. Knowing that the forestay over the 40 plus feet would stretch less than .25”. The stretch was estimated to add no more than 5 degrees rake on the mast when tensioned. I have a stout mast, some call it a telephone pole, which they say if it really was it would bend more. I have an adjustable back stay. When just snug (0.25-0.5 deflection of stay when pushed) the mast is in equilibrium. In this state when cruising across waves, I can observe the mast reacting to the chop. This is about 7 on the adjustable back stay. When I crank the backstay up to 10, (the adjuster has numbered markings that are about 1/8“ apart) the mast is steady and the fore/back stays are tensioned.

You should be able to do something similar to your backstay, by marking the line you use to adjust the tension.

This and your observations of speed/Weather helm should be better then average. Beyond that you need to develop polars for your boat and rig then test to the polars, and adjust till you achieve the proper results. Means going out and spending a lot of time practicing on the boat.

Of course that is a bonus. For such meticulous obsession.:biggrin:
 
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Jan 11, 2014
7,980
Sabre 362 113 Fair Haven, NY
Scott how do you tension the back stay, hydraulic tensioner or with a block and tackle?

One way to get repeatable adjustments is to mark the back stay and for various adjustments. Boats with hydraulic adjusters will tape a batten to the adjuster and then mark the position of the ram arm for various conditions. If you are using blocks a piece of tape at the various levels or mark the line, much the same way that reefing points are marked on the main halyard.

Also, because of the geometry of the backstay and the forestay, the tensions on them can be much less. The shrouds need a lot of tension because the pull is nearly vertical, the back stay has a very broad angle at the mast head and then the tension is spread again where it is split. I'm pretty sure, that in one of Brion Toss's books he talks about this or at least about the different angles and tensions for a rig.
 
Oct 26, 2008
5,047
Catalina 320 Barnegat, NJ
I have a simple block & tackle adjuster. Yes, perhaps my thought that getting the forestay to 15% of load rating is too much tension. I think somebody said that as a starting point, the forestay can be swung in about a 1' diameter if you were to grab it and push it around. There would be too many factors influencing the difference between the backstay tension and the forestay tension, i.e. angle differences of the wires, mast rake, swept back spreaders. At rest, I can relieve the backstay altogether and the mast stands. It would be an interesting problem to solve the forces, but I'm not going to do it!
 
Oct 22, 2014
16,409
CAL 35 Cruiser moored EVERETT WA
I have a simple block & tackle adjuster.
I would go for a sail, and make backstay adjustments in various wind conditions. The tensions (amount of line drawn in) made with the tackle will cause changes in the weather helm, boat speed, etc. When you identify a condition that meets your approval, make a mark on the tackle. Now go out and try to repeat this result. Once you have got the mark in a favorable location, make a permanent mark. Perhaps a colored thread sewn into the line. After you get the first mark the others should be relatively easier to identify the best trim. By the way, if you discover over time that the mark needs adjustment it is relatively simple to pull thread and put it in a different place.
 
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Jan 1, 2006
6,166
Slickcraft 26 Greenport, NY
I think OP is sane and on the right track. I may differ in that I think you should set the forestay length first and then tune the shrouds. The forestay tension is set with the backstay.