Question Fatheading a pinhead Minifish cat rig

[Bradrueb]

So I bought this minifish2 (for those who don’t know what that is, which is likely most of you because this boat is incredibly uncommon, it’s a cat rig Minifish, see the attached photos) at the beginning of the summer and I’ve been sailing the hell out of it. I want to get a new sail for it, because it still has the original sail from the 70s which is wearing down and has a few pinholes. My first thought was to just replicate the original sail (maybe throw on some classic sunfish colors) but I recently had a second idea: fatheading it. Now Ik it probably sounds pretty damn stupid, it’s a day sailing boat not a race boat, why would I do that? Well this boat preforms remarkably well in both light and medium wind, pretty comparably to a laser (I haven’t sailed alongside a laser yet but if my feel for it is right I would almost go as far as to say it’s faster than a laser though I don’t know how it compares when it comes to pointing ability and such) it’s definitely more nimble and maneuverable. So my question: would fatheading this somewhat performance boat be possible and if so, should it even be worth the effort for what I would get out of it? I personally know a sailmaker so the cost shouldn’t be too much of an issue, and I have access to a shop where I can manufacture parts relatively easily. I drew up a very rough sketch of what I was thinking of doing, attached below. For those of you out there who know your shit when it comes to this stuff and are cringing at my lack of knowledge, please be kind, I did little to no homework on this and I know it shows.

 

[wjejr]

Hi Bradrueb. I would be leery of adding sail area, especially at the top, to an unstayed mast. The additional force is not something the original designers would have planned for. Good luck in whatever you decide.

 

[beldar boathead]

Hi Bradrueb. I would be leery of adding sail area, especially at the top, to an unstayed mast. The additional force is not something the original designers would have planned for. Good luck in whatever you decide.

That’s a good point. I don’t think the mast would break, but it might flex a whole lot more than I’d desirable. How about just adding more roach? Keep in mind the COE would move back so you might get too much weather helm.

 

[Tops]

Very interesting...
Brad, If you wanted to put some numbers to the words, I could throw it into SailCut CAD for kicks and giggles since I am not an expert.
Does the current sleeved sail raise and lower with a halyard or is it more or less stationary?

 

[Charles Howard]

Looking at the portsmith numbers a laser is faster

 

[Fremont]

Why not? Experimentation is good. If it doesn't work, you can always recut the sail.

 

[jcsunfish]

Please try it and report back! I love a good thinking outside the box experiment like this. Currently in the process of attempting to put a full size laser sail on a sunfish despite it's many challenges. Often times these things are possible if you stick with it long enough to find new ways around the road blocks, (such as discovering a laser top section fits in a sunfish mast if you take off the bottom cap). Wishing I hadn't sold my mini fish, I could've used it and it's mast for different mast heights and experimenting with a smaller hull. Just don't get so caught up in the experimentation you forget to find time to sail! Good luck and can't wait to see pics and hear how it sails if you decide to proceed!

 

[Weston]

That’s a good point. I don’t think the mast would break, but it might flex a whole lot more than I’d desirable. How about just adding more roach? Keep in mind the COE would move back so you might get too much weather helm.

You have a beautiful boat! From a 2017 chart, I see that the Mini II is rated at 103 vs. 113.4 for the standard Mini. I am sure she points better than either the standard Mini or the standard Sunfish.

A couple of observations, as I have a Minifish, Sunfish and Super Sunfish...

The mast step for a Minifish is only 8.5" deep vs. 10.25" for the standard Sunfish. I mention that as a follow on to Beldar's comment to point out that there is less 'structure' to support the mast and having more sail area at the top of the mast could give you problems in heavy wind. Having said that, the standard Sunfish sail is 65 sq ft, and I believe the Mini II sail is only 60 sq ft, so you should have some room to play with there.

Regarding weather helm: I find that there is very little weather helm in a standard Minifish. On my Minifish I keep the gooseneck at 15" (measured from the start of the aluminum boom) and it seems to behave consistently in every range of wind conditions (8-25mph) . And this is with the original Minifish daggerboard (not the new high profile plastic boards). My other observation that may be of use is that I experience less weather helm in my Super Sunfish cat rg vs. the standard Sunfish. I believe you have the same sail adjustments on your Mini2 as I have on the Super (Vang, Cuningham and Outhaul) so we use those in place of the Gooseneck adjustment on our lateen rigs.

What does this mean to you? I don't think you'll have to worry too much about weather helm with either of the sailplan changes you or beldar are discussing. That's my guess anyway. Looking forward to seeing what you come up with!