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Sonofasonofasailor 12-04-2006 11:30 PM

Changing Rigging
 
Is it feasible to change a sloop from that of masthead rig to a fractional rig? Is it cost prohibitive? Would it effect the performance of the boat negatively or positively or not at all?

I ask these questions speaking in general terms but I'm curious if it would be worth it or possible to do this.

Thanks in advance.

Faster 12-05-2006 12:01 AM

If you look at most fractional rigs you will see that the mast is considerably further forward than most mastheads. Also since the boat is designed with this rig in mind the keel is likely further forward as well.

The biggest problem with this idea is that you are shifting the center of effort of the rig and depowering at the same time (if using the same stick). This will likely lead to increased weather helm and reduced performance. Even this approach would still require a fair amount of mods to the existing mast.

To turn a typical masthead boat into a good frac would most likely require shifting the mast forward, and making the main proportionately larger to compensate for the lost sail area of the smaller foretriangle. All of this has to be done with the intent of keeping the center of effort properly aligned with the center of resistance of the hull and fin.

Relocating the mast in the boat is a huge deal - chain plate/bulkhead relocation, moving partners if keelstepped, mast support if deck stepped, and doing all this in a structurally engineered fashion would be a huge undertaking.

It may help to know what boat you are contemplating doing this to.

If you really want a frac it would probably cost less to sell and buy another design that's better suited to your needs.

sailingdog 12-05-2006 06:49 AM

Is it feasible... yes. Will it affect performance... yes... does it make sense to do so... probably not. Will it be expensive... You betcha...

I know of a boat that has been converted from a freestanding rig to a sloop rig, to a cutter rig.... over the course of twenty or so years.

mike dryver 12-05-2006 10:36 AM

why would you want to if it ain't broke don't fix it. this does not make sense unless there is something majorly wrong with existing rig., but as stated previously anything can be changed or altered on your boat if you have the $$$$$$$$$ and time.

Sonofasonofasailor 12-05-2006 12:30 PM

I am not comtemplating acutally doing this and I don't have a specific boat in mind it was just a question that came to mind as I was reading more about different rigging. As I read your feedback I think that I knew the answer before asking the question but now I have confirmation of sorts. I guess better questions would have been 1)does the mast need to be repositioned and 2)is it a worthwhile task to perform (would the benefits be worthy of the task so to speak). Apparently the answers are yes and no as I suspected.

Thanks for your thoughts.

Jeff_H 12-06-2006 05:44 PM

While everything said above is essentially true, depending on the specifics of the boat, it is possible to get away with simply extending your mast a small amount above the jibstay (perhaps something less than 10% of the mast length) and add a longer luff mainsail. I have sailed on a Cal2-30, and gone up on the mast of a less than 30 foot Seafarer both of which this had been done on. I also sailed on a 1960's era Dutch boat that had gone to a fractional rig because of buying a used mast that was made for a fractionally rigged boat. In that case, a short bowsprit was added to balance the increased mainsail area.

Now then in most of these cases, the masts themselves were too stiff to get much of the shift gears on the fly advantage of a boat designed with a modern fractional rig.

Jeff

Giulietta 12-06-2006 06:51 PM

1 Attachment(s)
Jeff_H is absolutely right. It really depends on the boat, and how much of a change are you looking for. The greater the change the more costly (can we say costly??) it gets.

Lets see if I can explain this...

During testing with my boat, we tried different fractional positions to evaluate the ratings as we were moving the I, the J and P to see where the rating would benefit us in relation to sail performance. (keep in mind we maintain the main un-altered), and many times we had the mast jacked up to full up postion, and got better performance.

For this we installed a hydraulic jack at the bottom of my mast, that I use to add and remove mast tension, and thus control shroud tension also, now that is a good trimming tool, let me tell you. Great upwind and downwind!!

To compensate for a lower stay, we ended up instaling forward swept spreaders, (the sreaders are inclined towards the rear but curved forward) and compensate the reduction stay height by increasing leech area, because there is a hole in the rules and the "belly" is not measured.

To compensate for the belly, my racing genoa has batens.


I hope I could explain my case, because my English... . Its a cheaper solution for what you are looking for. Also one more thing, my stay works inside the shrouds. Look in members galleries for more photos of the belly genoa with battens.


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