Shroud tension Inter 17

I am looking for some advice on what tension to use for the shrouds of my inter17. Currently I am using the advice that I tension them by having one person hiking out and setting the tension accordingly. Is that what other Inter 17 sailors do?

Is there any other information I could look up on how to set up the Inter 17?

Other then the article at http://www.home.zonnet.nl/held20/I17tune.htm I have not been able to find any info on the subject.


Regards,
Martijn Balhuizen

http://www.cathouse1.com/F17_tuning.html

Marijn,

Welcome to the I-17 world!

I have the aluminum mast,, normal configuration. So, the info I give you works for my rig. I do not know if it is a general specification for the'R' version or not, ok?

I tried all aconfigurations. This is what works best for me.

I tighten the side stays tight. The guage I use is the when I grab the mast rotoator ( no sail up), and it has resistance, to the point where the rig 'screaches' about 50% thru the rotation and it gets hard to rotate to 100%. Then I have my spot.

When on the water, the forestay should not 'flex-reflex' when going over a wave. If so, the forestay needs more tension. Take up 'one hole' until this does not happen.

These setting are for Caribbean wind strenght ( 15-20mph) and 3 foot waves( +/- 1 foot)

I had my setting 'nice', and put new rigging up. I set the pins at the same settings. Guess what......it was not tight enough.

I suspect that the tightness of the rig keeps the mast from 'falling off' , thereby keeping the extreme pointing ability the boat is known for.

I have also noticed, that if you go to a single forestay configuratoin, you nave lost the ability to keep the mast from 'falling off' somewhat. the double forestay configuration appears to be the best upwind pointing setting.

Have fun!

Bruce
St. Croix
US Virgin Islands

Mike, Brobu,

Thanks for your excelent info and advice. I will get to work with these asap.

Yes, I have the alu mast, standard rigging with the mainsail and genaker.

Tx!
Martijn

Martijn

I'd fairly much agree with the above; but maybe even slightly tighter ! I have mine set up so that the leeward shroud hoes not really go slack (that you can see; but it is slacker as the mainsheet does streach the forestay and shrounds) when sailing upwind untill some downhaul is applied; I set my rig up with minimal prebend (20mm) and leave it there. The way I set my thension up was slightly different from Bruce :

1, Set the shrounds so you have the mast rake you want and then connect both forestays and the middle one that holds the pole up.
2, Tension the middle one until you have just a little bend in the pole
3, If the forestays are slack at all, then put them down a hole or 2 each side (using a mate hanging on a trapese wire to add tension to the shrouds) and bingo; If I remember I will measure the rig tension next time I am at the club (2 weeks time).

BUT always remember to do rig settings with the dolphin striker tight !

>BUT always remember to do rig settings with the dolphin >striker tight !

Could you elaborate on that? I have never really worried about the dolphin striker.

OK.

The dolphin striker is the only thing that stops the front beam bending (apart from the strength in the Alu.).

So if the Dolphin striker(DS) is slack; the front bean will bend more than if it is tight.

Now think about what happens when you pull the mainsheet in; You are pulling the sail in that is :

A; Pressing on the mast which is pushing the mast downwards - Ergo the front beam will try and bend down in the middle, when you go out on the wire it just gets worse
B; At the same time the shrouds are lifting the side of the hull - Ergo the front bean will try and bend up at the end.

So therefore there needs to be some prebend in the front beam to counteract this.

How much ? well I did some (not very accurate experiments) by drawing a pencil line across my front beam level with the top of the hull (used the Tiller extension as a ruler). When I had the mast rigged then tensioned the DS so I had about 5mm defection upwards having set the rig tension.

I went sailing in a fair breeze and looked along the front beam best as I could and decided I could still see a little downwards bend. I then came ashore and wound on a little more DS to about 7mm and it has been there ever since.

I will fully admit that this was not very scientific; but it appears to be about right. If the boat feels sloppy, it will either be too little DS or the tramp is not tight enough.


BUT remember to take ant DS off before you try and un-do any of the bolts !!!!

Also, don't go too mad with it as you will be also changing the geometry of the hulls !

Ok, got that. I will check the DS. Mainly I will tension up the whole rig, shrouds side and front.

tx again!