F25 mast and sail configuration

[rnyc]

Hi all I am considering buying a F25 after having owned and sailed a J22 successfully for some time. The reason being that I am moving to inland sailing after spending most of my time sailing at the coast where the winds are usually stronger. In addition I will have to part company with my crew who have been together for two years.
I have been warned that the F25 cannot be compared to a J22 which I agree with but then again you can't sail a J22 singlehanded with much success.
Looking at the rig my question is could one lift the mast (round type) by sleeving and inserting an aluminium section onto the foot of the mast and increasing the height by say 2 to 3 feet and then lowering the gooseneck and increasing the mainsail luff by approx the same length and making the sail a square top. Obviously the rig would become more powerful and one would have to reef earlier.
This would increase the area to approx 330 squarefoot and according to the SA/D ratio this would take the rating into the 20's which would put it in the racer class.
The square top would increase the light upwind performance significantly whilst increasing the weather helm. How much weatherhelm does the standard F25 have when sailing closehauled.
Am I smoking my socks or do you all think this might work?

[Teke's Pride]

Hi RNYC,

Welcome to the group!

I don't know why you couldn't extend the mast as you describe as that is very similar to the way the tabernacles were inserted into the masts just above the deck on the Freedom21 Shoal Draft versions. The only thing is that it may affect your boats balance and heal. You might want to consult a naval architect or someone more familiar with sail dynamics before you attempt something like that. It would defiantly affect your PHRF ratting if you plan to do any racing.

As to square topped mainsails. Some Freedom21 owners have converted (Moose McClintock of DP Sailcloth Technologies for one); in fact I just ordered one from Schurr Sails in Pensacola, FL this evening. Schurr sold me on his design mainly because he did one for a Freedom25 just last year.

Fair winds and following seas,

[rnyc]

Hi Clark
Thanks very much for the reply. I would very much like to hear your experiences with the square top main especially upwind in the light stuff.
I have spoken with our local sailmaker and he says that the boat will become more"tender" as the sail area increases but I am more interested in the upwind performance in the ligter breezes as I don't particularly want to set a staysail as this tends to displace the concept of easy single handed sailing.
I realise that my rating will alter but Iam more interested in staying with the top end of the fleet in clear air etc whilst racing. If the handicap PHRF puts me further down the fleet in the results so be it.

[Michel]

I'm not so sure this mast extension at the bottom is wise. These masts are designed and built with the location of the deck partners in mind. You might need to insert the aluminium tube much further, say up to 1/3 of the mast and make sure the tube is snug inside the mast. This might be difficult if the gooseneck area is beefed up on the inside. You might alto consider extending the mast at the top; the forces on the mast are much lighter there. You might also consider leaving the mast as it is and having a new mainsail made with a square head, giving you more sail area at the top. This is a common route on Freedoms that need more sail area.

[Teke's Pride]

Don't wait for my data to make your decision as I just ordered the sail last night for delivery in late summer or early fall (I choose the delivery time frame for a better price).
You should talk to sailmakers who have experience with square top mainsails on Freedom rigs!
Here is a list of lofts/designers who I know have made such sails:

SCHURR Sails
Hunter Riddle
490 South "L" Street
Pensacola FL 32502-5209
Work 850.438.9354
Fax 850.438.8711
Cell 850.380.3531
http://www.schurrsails.com

DOYLE Rhode Island
Todd Johnston
1 Division St.
E. Greenwich, RI 02818
T (401) 884-4227
F (401) 884-4270
tjohnston@doyleri.com

SANDERS SAILS
Bath Road
Lymington, Hampshire England, SO41 3RU
Tel: +44 (0) 1590 673981
Fax: +44 (0)1590 676026
http://www.sanders-sails.co.uk/contact.htm

[rnyc]

Hi Michel
Many thanks for your input and you make a valid point. Question how would one increase the top of the mast? With an Aluminium sleeve? or try to manufacture a Carbon fibre tapered tube. Is the mast at the top normally not tapered for the last say 200mm in which case an aluminium tube with internal diameter to match the OD of the carbon fiber might work and would certainly be a lot easier and cheaper. One would leave all the other sheaves in the same place and just move the main halyard sheave up to the top.

[Michel]

I have no idea what the diameter at the head of an F25 mast is. You might try and and find a discarded CF mast or an other suitable piece of CF (windsurfer masts?) to extend the top. Having a mast maker extend the top end of your mast could also be an option; here in the NL's these companies do a lot of customisation and alteration on CF spars. May not even be very expensive.

[numbknots]

I think you might try extending the bottom of mast before tackling the top. Especially if you are going to a sq top sail that would be quite a bit of pressure at the top twisting off.
I dont know if the f25 is deck steped or not. If the mast goes through to the cabin sole then your splice would be inside the cabin top and the pressure at the splice would be nominal in comparison to above deck. That is how I repaired the mast on my F 28 ck. I havent had any problems with it in over 3 yrs now, and I have sailed it in very windy conditions. I sleeved the inside with and aluminum tube about 1/4" thick and because it wasn't an exact fit I had it turned down by a machine shop here to match the inside diameter of mast. There were a few other details that went with the job but it worked. Good luck, Numbknots

[Michel]

I placed an article by Eric Sponberg here on the board somewhere about building freestanding masts. He used to be Freedom's mast designer. There is a graph in the article that shows the strength needed in each part of the mast.

[rnyc]

Has anyone put a square top mainsail on a F25 and what was the effect on upwind performance?