Bimini in a Tiki 26

[Alexandre Ferreira]

I need to have a very good sun protection im my future Tiki 26. I wonder if it would be posssible to add 30 or 40 cm to the mast lenght, so may be I could try to build something like a fixed bimini (like a roof) as I saw in a 30 ft Tiki picture. On this bimini, once possible, it also coul be installed a solar battery charger.
Hope to hear from you. Thank you.

[Alexandre Ferreira]

Thank you for your information about mast lenght. I'm still working in the boat model (1:10) and I'll try to add some suggested changes I had from my meeting with Luis Figueiredo (member of this group) who has a big experience in catamaran building and sailing. I'll keep people updated with my project.

[Luis Sa Figueiredo]

Alexandre - This is Luis trying to find your email to contatct you Pvt. We moved to another address but the phone number remains the same. I will be away until next month. As soon as I come back I will phone you. Regards, Luis.

[Gorby]

Hello Alexandre,

It has been a while since your last post about mastlength but...

I too want to make the mast longer. After making scarf joints I will have about 28ft of mastlenght. Why cut it away? 1-You can raise the mainsail for better sight and a sunscreen. 2-The wind always blows a little harder up high - away from the friction of the seasurface. So raising the sail 2ft in light winds is a plus. 3-You could make a working jib that has a higher aspect-ratio and thus higher speed potential. 4-Any light-air foresail can be just a little bit bigger.

The only penalty is the extra weight of 2ft of mast which is... maybe 2kg. Seems like a good deal to me!

Greetings from the Netherlands,

Gorby

[Duncan Clausen]

Hi guys! Just a thought on making the mast longer. All one really needs to do is add an extension at the mast head so as one can raise the peaking halyard. This will allow the gaff (and hence the main sail) to be raised a little higher. The rest of the mast would stay the same. What'ya think?

Duncan

[paul anderson]

duncan,howzit,how much do think you would extend the stick by for this purpose?

cheers paul.

[Randall S Anselmo]

A few comments on things people are probably considering, but that I haven't seen voiced yet here.  One is that I do feel, after only a few months of leisurely sailing my T26, that sun protection is a serious issue on these boats.  I have practiced medicine in Florida and Australia, and skin cancer is no joke, not to mention the general discomfort, dehydration, etc. of constantly beating solar radiation.  This would be even more of an issue for long range cruising, I believe.  Raising the foot of the sail in order to provide some kind of shade structure is a very good idea. Next time I am aboard, I'll measure the distance from the cockpit floor to the foot of the sail to give an idea of how much one might want to extend the mast for this purpose, and post it here.

This idea needs to be carried out with caution, though.  I am no naval architect, but raising the mast does have implications for ultimate stability on a catamaran.  While I love the speed that a catamaran is capable of, I was drawn to Wharrams because James is not greedy about speed, but rather, seems to be focused first and foremost on safety.  The Hei Matau will never be able to compete with a Stiletto or a Reynolds for speed, but I bet she'll outrun any 26' cruising monohull, and still deliver me and my family with the mast pointing up in any kind of weather.  I would consult JWD or another knowledgeable source before modifying the rig.

Lastly, when extending the mast, one should consider that one of the reasons for the mast length as designed by JWD was surely to keep it the same length as the hulls so that it would be manageable on a trailer.  Extending it a few feet would not cause a big problem with trailering, but it should be kept in mind.

[paul anderson]

hey randy it would be cool if you got those measurements,i am building my mast to 27' but would like to know how much height that leaves me with in the cockpit.it seems you have total confidence in the ole tiki 26, this is good.

p.s any thoughts on a bimini set up would be welcomed.

[Randall S Anselmo]

G'day Paul,

Got those measurements, but I must qualify that I tinkered with the mast rake this summer, and had it at around 10 degrees, rather than the 4 degrees specified on sheet 18 of the plans.  I haven't sat down to work out the trigonometry, but obviously, if the mast is raked less, one would have a little more clearance, therefore, these actual measurements should serve as a good, if not overcompensated, minimum clearance.

From the floor of the cockpit to the tack of the mainsail, I measured 36 inches (91.5cm).  From roughly the center of the cockpit floor to the foot of the mainsail, I measured 39 inches (99cm).  From the aftmost cockpit floor to the foot (not quite the clew), I measured 48 inches (122cm).  This was with the throat halyard, then the peak halyard hauled as high as I could get them, and very light downhaul.  The Hei Matau's mast is exactly 26 feet (7.92m)long, and the top of its step is 1 1/4 inches (3.2cm)above the mast beam.  The sail was made by Lee Sails, and as far as I know, cut to Wharram specifications.

As you can see, not much clearance for a bimini in the standard configuration.  As for design ideas, there is a nifty awning arrangement pictured on a Tiki 30 on page 61 of the Wharram Design Book, but it doesn't look like it would stand up to much wind.  Then there are the awesome and more permanent affairs on Boatsmith & Budget Boaters' T30's.  I haven't yet seen the optimal setup on a T26. Hope that helps.

R

[kim whitmyre]

Hi Sailors! 10 degrees! How is your weatherhelm, Randall? Scott Brown once mentioned on his board that too much rake would bring increased weatherhelm, and hurt pointing ability. Too little rake can produce lee helm, something to be avoided at all costs.

 

I have my mast at the designed 4 degrees, which puts the mast head very close to 22 1/2" aft of the mast beam measured from directly under the 26' mast. My mast is now 27', and with the main fully raised, there is ample room for me to increase the height of my dodger/bimini by at least a full 12". Whether I will or not is the question! At present, (I'm 5' 9" in height) the dodger is barely high enough, though I can sit under it. You can, and likely have, see my dodger on my page here.

 

Next time I have the main up, I will do some measuring and report back.

[Randall S Anselmo]

I definitely noted more weather helm with the rake at 10 degrees, and while not excessive by any means, I will go back to the specified 4 degrees next time I set up.  We had an informal race with a Catalina 25 and a Cape Dory 27 in 10kts of wind, and they definitely outdid us on the weather leg, but we more than returned the favor on the downwind.

Did you make a new mast, or modify the old one? If you modified, how?  Has it affected your heeling moment and stability? I have indeed admired your dodger/bimini, and thought about making something similar.  I'm guessing that it still leaves the helmsman exposed, though?  I'd love to have something about 3 feet fore to aft, spanning the aftmost portion of the cockpit.

kim whitmyre said:

Hi Sailors! 10 degrees! How is your weatherhelm, Randall? Scott Brown once mentioned on his board that too much rake would bring increased weatherhelm, and hurt pointing ability. Too little rake can produce lee helm, something to be avoided at all costs.

 

I have my mast at the designed 4 degrees, which puts the mast head very close to 22 1/2" aft of the mast beam measured from directly under the 26' mast. My mast is now 27', and with the main fully raised, there is ample room for me to increase the height of my dodger/bimini by at least a full 12". Whether I will or not is the question! At present, (I'm 5' 9" in height) the dodger is barely high enough, though I can sit under it. You can, and likely have, see my dodger on my page here.

 

Next time I have the main up, I will do some measuring and report back.

[kim whitmyre]

As obtained, the central section had been replaced with 1/8" x 5" aluminum tube. The masthead and mastfoot had been sized to insert into the tube to the depth of 18" or so. The masthead was rotting below the blind sheave, so during my spring 2009 haulout, I took the mast home and rebuilt the head.

Here you can see the mast at the left, sleeve and new top on the ground at right. Mast looks larger due to being off the ground on horses. The "crowns" cut at the ends of the sleeve prevent stress fatigue that a simple straight cut would cause.

 

The slot is cut to allow the sleeve to compress for insertion into the new top. I put adhesive on the sleeve before the actual insertion, and tapped flathead screws in an offset pattern around the mast as well. The screws were well smeared with Tef-Gel prior to setting.

Here is the new top with standing rigging fittings and internal jib halyard sheave installed.

My seat-o-the-pants meter can't detect any significant difference with the extra foot of mast height. The new sails likely have more effect.

Yes, I too have thought about an extension to the dodger aft. One item that gives me pause is the jib sheets:

Any dodger extension must accommodate the jib sheets in their windward mode! ;~)

 

[Randall S Anselmo]

Thanks for the detail photos Kim.  Excellent thinking on the crowns.  I may try something similar to get the clearance I desire.  It's good to know that you didn't sense any obvious increase in heeling moment.  While it has to increase, you've answered my question of "how much" to my great satisfaction, in that is does not seem significant.  

kim whitmyre said:

As obtained, the central section had been replaced with 1/8" x 5" aluminum tube. The masthead and mastfoot had been sized to insert into the tube to the depth of 18" or so. The masthead was rotting below the blind sheave, so during my spring 2009 haulout, I took the mast home and rebuilt the head.

Here you can see the mast at the left, sleeve and new top on the ground at right. Mast looks larger due to being off the ground on horses. The "crowns" cut at the ends of the sleeve prevent stress fatigue that a simple straight cut would cause.

 

The slot is cut to allow the sleeve to compress for insertion into the new top. I put adhesive on the sleeve before the actual insertion, and tapped flathead screws in an offset pattern around the mast as well. The screws were well smeared with Tef-Gel prior to setting.

Here is the new top with standing rigging fittings and internal jib halyard sheave installed.

My seat-o-the-pants meter can't detect any significant difference with the extra foot of mast height. The new sails likely have more effect.

Yes, I too have thought about an extension to the dodger aft. One item that gives me pause is the jib sheets:

Any dodger extension must accommodate the jib sheets in their windward mode! ;~)