U20 Class Member's Forum

General Category => U20 Boat Maintenance & Care => Topic started by: Mike Myers (RWS) on June 19, 2020, 02:58:42 AM

Title: Forestay Length
Post by: Mike Myers (RWS) on June 19, 2020, 02:58:42 AM
Hi all,

We have a Carbon rig from Forte, and I noticed the rake is super aggressive so I measured it yesterday. We are just barely within the class maximum rake, with a distance from the main halyard entry to the stern of 34' 9 and 1/8th.

The boat gets sailed on lake superior, where conditions can get pretty intense, and the current crew is running light of the max weight limit...so having a max rake/max power rig setup doesn't seem like a brilliant choice.

I want to move our rake closer to max forward, (35' instead of 34' 9'' from halyard entry to stern), but I'm unclear on the math to make that change. I'm not certain that simply shortening the forestay by 3 inches will lead to a 1:1 change of 3 inches at the back of the boat...my gut says probably not.

Is there any official class guidance for forestay length that I'm unaware of? I found Tim porter's post about standing rigging lengths, and my forestay matches that, but I suspect the forte mast has a slightly lower anchor point for the T-Ball and it's changing my rake angle,  which means I need a shorter forestay.

Is there any rule against an adjustable forestay? The way I read the class rules, it seems the forestay can be any length as long as the rake measurement distance remains within the three inch tolerance I mentioned above.
Perhaps I just put a turnbuckle on my forestay that allows me to lengthen or shorten as needed, but stay within that tolerance?

Any other suggestions for reducing rake angle?



Title: Re: Forestay Length
Post by: Tac Boston on June 19, 2020, 01:36:51 PM
I would think that with the Forte being as stiff as they are you would want to set your boat up at max rake. I think in breeze with either the C-tech or tin rigs we end up sailing with a even shorter distance/more rake. I am pretty sure we have only ever sailed right around max rake.
Title: Re: Forestay Length
Post by: TimPorter on June 19, 2020, 02:44:12 PM
I agree with Tac.  In my opinion you should always sail with max allowed rake on this boat.  This is especially true for a stiffer rig. 
Title: Re: Forestay Length
Post by: Mike Myers (RWS) on June 19, 2020, 05:55:34 PM
Thanks guys, I guess well stick with what weve got for now then. Im still curious about how youd determine forestay length for this boat if you were trying to reduce rake, but well stick with this length for the time being. Is an adjustable forestay something anyone has done?

Somewhat related: how have people addressed the gap that forms at the front of the mast base due to the angle the mast sits at? The guys at forte mentioned sanding the base down to an angle that matches the rake, but that would shorten the mast by nearly an inch and probably end up causing a more exaggerated forestay tension issue.
Title: Re: Forestay Length
Post by: TimPorter on June 20, 2020, 01:15:36 AM
The only reasonable way to reduce it is to get a shorter pigtail. 
Title: Re: Forestay Length
Post by: Dean Nelson on June 20, 2020, 01:35:35 AM
Reminds me of high school geometry.  Shortening the diagonal forestay on the smaller triangle will result in a larger increase in the length of the larger triangle top of mast to transom.

For aluminum masts, the gap at the front of the mast base is used when forward mast bend occurs...the gap will decrease.  Granted, carbon masts are much stiffer, but the same principle applies.
Title: Re: Forestay Length
Post by: Mike Myers (RWS) on June 20, 2020, 11:48:44 PM
ok thanks guys. Tim, a shorter pigtail is exactly what I was thinking.