RE: Boom/mast to sail measurements

Question
QUESTION: Hi Windlover,

Well the plot to get the old windsurfer up and running again thickens<g>.

Today I got the used chinook mast base (which came with a nut - but I see I am going to have to order the Mistral Slider Nut to make it work )

http://www.chinooksailing.com/products/product_info.php?products_id=287

So now that I had my used short Chinook mast extension I decided to rig the sail and see how it went.

The first clue was when there was no where near enough downhaul line<g>.

Even downhauled the 4-6" you said to expect, the boom would have still mounted near the top of my head ( I am 6' 1" ).

So at this point I am thinking that there is no way that sail would work with my mast (or was the right cut - despite it being a 5.2 m2 sail by my calculations).

I decided to try the boom and discovered that even if I ran the extensions to the max lenghts, it was still several inches too short.

So the old Windsurfer brand sail was definitely NOT the sail for this rig.

I am guessing that someone got the board, bought a used sail with no idea of how to get what they needed, got frustrated when it did not fit and the entire rig wound up at Goodwill...


But here I am - still plugging along<g>.

So the mast is just over 486 cm tall.

The boom - measuring from the inside of the part that touches the front of the mast to the max distance of what will fit inside (not allowing for any outhaul) is 215 cm.

From that, what size sail do I need to be looking for?

From the photos and videos I see, most sails (when downhauled) seem to be 4 to 6 inches off the board and I do understand that my adjustable mast extension (or a longer one if needed) would allow me to tweak that.

But what am I looking for on the boom?

I had let the boom out about 4" (thus the max measurements above), but would really like to know what to look for in a used sail.

Thanks as always for your expert advice!

:-)

Charles

ANSWER: Hey Charles,

The Mistral slider nut is designed to convert a movable mast track to a fixed mast track. Remove your track and then remove the moving parts. Then install the slider nut and put the track back into the board.

Your mast would have been listed as a 490cm mast. Way to long for your 5.0m2 sail.

To determine what sail size your boom will work with, measure from the mast end to the boom end with the extensions all the way in and then with the extensions all the way out. This will determine the range of your boom length. Sails will list boom length on them.

Hope this helps.
Keep on sailing,
Windlover



---------- FOLLOW-UP ----------

QUESTION: Thanks for the info.

I remembered your instructions for modifying the track, just have to get the Mistral Slider Nut as it is larger than the one that came with my used mast base.

I sent another message after this post (but it was marked "private"), not sure if you saw it or not.

A part of that was wondering if you thought that this sail:

http://www.mauisails.com/sail.php?id=5

would work with my mast.


I found a used one that is a 6.0 m2 and it shows luff at 456.


With my mast being 486 ( 490 per above ), would this work with my short extension?


The boom measurement is 187 so it seems it would work with my boom as the adjustable range seems to be 188 to 213.


Also I wondered was the stiffness of my mast as I saw some posts about those sails being cut to favor the MauiSails masts.


Finally if a used sail has a small repair in the monofilm should I avoid it?

Thanks!

Charles

Answer
Hey Charles,

Your mast is too long for the 6.0 so it doesn't matter which extension you use, the mast is just too long to start with.

Stating that a particular sail favors certain masts is getting a bit too technical. If the sail requires a particular stiffness, then most masts of that stiffness will work well for that sail. Sail makers will say that a specific type/brand of mast will work best for a particular sail. That is the optimal set up. Bottom line is that if the mast matches the length and stiffness, the sail will work on it.

As for repairs on monofilm, you can buy monofilm repair tape that works well to prevent further tearing. Be sure to have at least an inch or more tape all around the tear and place a piece on both sides of the sail. The thing to look for in a used monofilm sail is that it has mimimal creases and hopefully no tears.

Hope this helps.
Keep on sailing,
Windlover