14' Trimaran Restore and Upgrade - Supernova

Boat Weight

Ok so Corley got me wondering what my boat actually weighs so I did a bit of research and came across this:

http://www.nauticaltrek.com/100-4m50

Awesome data base for all sorts of trimarans.

Shows me the following in a side by side comparison to a Weta:

Weight:

SuperNova = 90kg
Weta = 125kg

So much for old technology fibreglass construction and aluminium...

Sail area:

SuperNova = 12m2 with a 133m2/t rating.
Weta = 11.5m2 with a 92m2/t rating.

Winner = SuperNova !!!

Speed:

Various reports from both craft in varying conditions.

To be fair even though on paper the SuperNova has the greater spec I do not think with it's near 30 yo hull design that it can match a Weta.

The Weta has similar length and volume ama's but it's main hull is a much cleaner shape than the SuperNova, and should be given that it has over 30 years of experience built into it.

Main difference in the Weta seems to be the wider rear that helps to push it up onto a plane earlier.

So for my SuperNova to compete with a Weta I need to broaden the tail of the main and also modify the ama's to produce added lift.

Not a problem. I've got 35kg of weight I can add to match the Weta and over $18k in my pocket to do it seeing that I only paid $300 for the SuperNova

Come on there has to be a Weta owner out there that will bite?

Here let me help out...

Weta owner #1: At least mine sails

All good fun but the real world is calling, keep watching this space and I'll give updates on build up as we go.

Hydromann

 

Update

So after tossing around a number of ideas from bow scoops through to complete new ama hulls and foils I gave up and simply went out to the shed and started cutting stuff up.

Figured my main objective is to get it on the water in a stable format so the family like it (and then I can talk them into a bigger boat).

So some images below..

These show the steps I took to get to the final style, I will need to add some material and finish shape the design to give me a NACA foil profile.

Last image shows foil profile at the bow but I think I'll double the thickness of the foam and shape along the whole so it is like a very long foil profile.

Thinking is if it does go fully under then at least it will develop lift due to the foil shape, granted that will only happen if we are still moving forward but it will also provide some add buoyancy being made of foam and carbon fibre. So in theory a win win.

Hydromann

 

I only sailed a Supernova once and it was centuries ago, but I don't recall it nosediving much. Lock Crowther tried fixed bow foils on an A Class eons ago and found that once the bow is pressed down beyond the angle of attack, you flip so fast you can't see what happened. The trend for some time has been to clean up the bows so they don't make the boat decelerate and therefore cause a nosedive; will the foils work like that?

Would a T foil on the rudder work better? With an Int 14/Stevo angle adjustment on the foil you could add lift to the stern when you need to and then have the option to drag the stern down when you want to avoid nosediving.

I had forgotten how slim the Supernova floats are; it's a very pretty but rather old fashioned shape. Personally I'd wonder whether the low aspect bow foils will add worthwhile lift or cause excessive drag.

 

Thanks CT249, appreciate the feed back.

As you know with boats there are a myriad of options that will change the performance.

I've done a fair amount of research on bow foils / canards etc. A lot of Hobie users swear by the little ones you add on to the 14 an 16 cats.

Again there are many arguments for and against, I mostly relate back to my earlier surfing years when "new" narrow nose boards like teardrops where being introduced.

Those things would nose dive so easily if you didn't have your weight back enough on the take off drop, granted the manoeuvred easily but I sure did not like them. Much preferred the fish shapes that are still popular and have more area in the nose for planing through a steep drop.

So my way of thinking is that if you have sufficient area to stop the nose from fully submerging then you have a better chance of avoiding pitching. Also with the idea of having the canard shaped like a foil so that regardless of position in the fluid it will still generate an upward lift and direct the nose to the surface if it does dive. Added to the foil aspect I will also have a significant buoyancy gain.

Anyway the bow canards / foils are one of many ideas I have thrown around in my head and modelled in sketch.

I had considered rudder T foils but because it is a single and rather smallish rudder and due to how it is fixed to the main hull not being the strongest design I decided against it.

However you have gotten me thinking again and one thing I have not considered is the dagger board, might have a better look at how that all sits and see if there is any potential to modify. I was toying around with making a new one that is lighter and also had looked at the quantum fin design for surfboards and considering how that might be adapted.

While the Supernova floats are relatively thin I don't think that they are thinner than the Ninja floats. Have watched video of both and was more impressed with the Supernova than the Ninja. Also a local here has a Weta and the floats on that are no bigger than the Supernova.

As for actual bow foils / canards the Surtees S22 has them and seems to perform very well. Len designed them to act as stabilisers and reduce pitching / see sawing. The also add some lift to the bow, gotta say he has made a nice day sailing cat.

http://www.s-boat.com.au/v

Also considered doing similar to the Supernova but decided to work with materials I have in hand. If I added bow canards I would want to make them pitch adjustable and it all got too hard for me.

Thanks again,

Hydromann

 

Any progress on this project Hydomann? I'm interested to hear how it all goes.

 

Stalled

Hi Corley

Thanks for asking. Yes and no. I have been repairing the main hull and akas, more issues than originally anticipated after a number of float tests found many small holes, had to pressurise the hulls to see where they where. Seems to be many fractures from what looks like a reef strike.

Also biggest issue was that the mast was bent, I had not seen this when I first purchased. They had straightened it out and had put tape over an area of the sail channel which was found to be split. Long story short I have had to straighten and weld this area and am considering a sleeve to further strengthen. Also looking to find a Hobie 14 mast and retrofit in place of existing if possible.

Also need to fit new ropes for the sail and a few new fittings need to be made.

In the mean time I am selling my catamaran so I can buy another little trimaran that needs less work and we can use straight away.

Hydromann

 

Hi, I have a supernova trimaran its fun boat to sail.