thoughts on mast extention

[paul anderson]

hello all

I was looking at maybe extending the mast on my tiki 26 build to accomadate a bimini/targa top.this topic has been discussed before but would like more input into this idea.would a  2'' extension bring with it more stress on the rig etc.

cheers paul.

[Geminidawn]

2" (inch) ? Surely you mean 2' (foot). Do you mean to jack to whole rig higher to have more room on the deck and still keep the same sail size? If so then this would definately effect the whole stability of the vessel as you would be raising the centre of gravity, centre of effort, the metacentre and the righting lever . It would be possible to recalculate the sail shape without sacrificing its size but the 2' you're losing on its base is better served calculated into its luff and not the top, therefore you'll keep the same center of effort but you'll need a longer boom if you're using one. I'd talk to your local sailmaker first see what they have to say, they may be able to tell you how a subtle change in sail shape to accommodate a bimini will effect the overall performance of the vessel. If it is just 2" (inch) then I don't think you have that much to worry about.

[Ann and Neville Clement]

I agree with Geminidawn on this, but there are likely other considerations:

 

If it is two feet, then you might want to draw it out to see how it looks.  Might look wierd to have that sail so much higher.

 

If you add to the aft edge of the sail, you might get stronger weather helm.

 

 

[boatsmith]

I added 3' to the mast on our Tiki 30 and used the stock sail. Yes it does move the center of effort up which does affect the stability. If you don't hoist the sail at all the stability will be awesome. I have sailed the Tiki 30 several times in 30 knots of breeze and could not get a hull to lift. This was in flat water, without ocean swell or waves. Offshore I would reef for more safety from the combination of wave and wind action flipping me. I don't mind putting in a reef. I think that a boat with a properly sized rig should require a reef at about  18-22 true. If it doesn't then how can you sai lwell in winds of only 5-6. If you don't want to sail the boat then maybe the sails should be very small and you can just sit in the back and sip cocktails with no worries. One thing about Wharrams is that they are designed stout for hell and with low horsepower rigs. There is room to tweek them to suit their owners and many (most)  modify their boats to a greater or less extent.

[kim whitmyre]

When I sleeved my mast top, it ended up about a 1'/305mm longer, or 27' in length. As boatsmith says, it is up to the cap'n of the boat! A good cap'n reefs early! ;~)  On the plans, JW says a lightly loaded tiki 26 should put in the first reef at 19 knots true. Definitely! On a beam reach, with good sails, at 19 knots a tiki 26 without a reef would be screaming through the water. Only a thoroughly experienced sailor, IN A RACE, should attempt it.

 

Without trying for speed, with the full rig up, in 15k, gusting to 20k, Vaea was at 13.6k. This was on a high beam reach. The lee hull was pushing deeper into the water, kicking up spray into the front of the cockpit. My hand was at the mainsheets. . .Dropping to the first reef would have likely relieved me of the mainsheet watch; instead I dropped the main to leeward, and the lee hull came up, making the boat much more comfortable.

 

Now to the point, Paul already has his sails, and is asking about a taller dodger. With a well-designed dodger, increased windage would hopefully not be extreme.

 

As Rory says, a fully loaded cruising boat is a horse of a different color, and is apparently much less tender. Nonetheless,  I tend to agree with what a Kiwi sailor said on Scott Brown's board: " Speed is life on the water." In many ways!

[paul anderson]

ah yes, feet i mean as kim says i have my sails already ,so the centre of gravity may be affected as well as i presume would be the load on the stick and rigging,but then boatsmith thinks this no big sweat.thankyou for your replies i have a lot of thinking to do.

cheers paul. 

[Rogerio Martin]

My mast will be 40 cm higher than original, becouse the same problem (bimini)

[Duncan Clausen]

Hi Paul, on my t30 the mast was a little longer, but we normally sail with the sail in the as designed position. It is nice thought to have the option of raising the sail higher up the mast - this is the beauty of the rig design. Common sense needs to prevail as when to reef! One can score a little extra clearance by raising the mast crane and hence the peaking halyard without having to change the main mast /shroud dimensions. 

 

Some sort of sun protection is a very good idea in this neck of the woods - hole in the ozone layer and all that.

 

Cheers Duncan.