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Wondering if anyone had the experience of reducing the thickness of Ply to lose weight at a Tiki 21

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Salve Claudio!

No, I have no experience with thinner ply. We used 6mm okoume for hullsides and decks. But I have to say I always found the structures thin enough. The hullsides noticeable give way to big waves and it took me some time to fully accept that only 7mm (ply + glass fiber + paint) seperate me from the ocean.

I wonder why you want to reduce weight. In my experience some weight does absolutely no harm to the boat performance. I found that some ballast reduced heeling and leeway quite significantly and because of the bigger momentum it also made tacking a lot easier. But of course I am a lazy cruiser and not a racer.



The Tiki 21 weight around 350kg unloaded. A good part of this weight comes from the beams and rigging. Add an outboard engine at say 18kg or up to 25kg, plus a crew at say (1) 75kg or (2) 150kg, plus some kit. This gives say 450kg. Now you reduce the ply thickness and save what 25kg or less? So around 5% weight reduction with one crew and less with 2 people.

I renovated my Tiki21 last year. I replaced a section of ply where an impact tore a split into the ply.

When you're in the hulls and sailing fast, you feel unnervingly close to the water.

I can think of a few improvements to the Tiki 21, but I don't think I would build it from thinner ply. 

Good luck with your project.



Hey Claudio,

Pius and Ian are right. The Tiki 21 performs fine when loaded. But if you want to lose some weight DONT trim down on material thickness. Instead lose the solid wood deck and fit a net trampoline instead. Trim down on your cruising gear. It really is surprising how little equipment is really needed on such a small boat. Cookie is of course made with GRP hulls but about the same 5-6mm thickness. Go sailing on a beam reach in 40kts of wind and you will be happy to have every mm of hull thickness when a wave crests against the side and pounds the boat 60 degrees off course in less than a second!!

What are your aims in reducing weight?

Hi Rory,

increase speed.
Yes you are right.
I lose the solid wood deck and fit a net, like Cookie
and reduce my crusing gear.
No motor, only solar panel.
Thanks very much for your commets.


The mast on my Tiki21 is made of carbonfibre and is VERY light. I don't know the weight of the wooden mast in the plans, but it's probably several kilos more. My shrouds are stainless steel, but you would probably save a little weight with dyneema rope instead. 


Very interesting your information
Could you tell me the specifications of carbon mast?
What do you think about carbon rudders?
Thanks a lot

Hey Claudio

How old are your sails? Another way to maximise speed obviously is to have well made sails and a good selection of jibs / spinnakers to play with.

I have no sails
I'm building
you get some good advice for sails ?

Westaway sails in the UK made both my sets of sails. First set lasted 20 years and sailed Cookie round the world with good durability. 2nd set fitted to the boat in 2010 for the Jester challenge across the Atlantic and now have about 8,000 miles on them. Brilliant sails and very helpful staff at Westaway. My sails are true ocean going sails whereas the Jeckells Sails I have seen on other Tiki 26s I would class as more day sailing coastal sails. I'm sure Jeckells would upgrade their standard sail specs if asked.

Cheers, Rory

Thanks Rory



My carbon mast is 6,60 meters long and 37 cm circumference. I don't know the wall thickness. According to the builder of the boat it's a spinnaker pole from an Americas Cup boat. I don't know the weight, but you can easily carry it around with one hand.

I guess carbon rudders would work. I wouldn't know how to make them though.

Good luck,


Claudio Calcagno said:

Very interesting your information
Could you tell me the specifications of carbon mast?
What do you think about carbon rudders?
Thanks a lot


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