So are you going to use the rectangular Mozzie beams and fit them to your new F16 hulls? I ask since the F16s generally seem to go with larger scale round beams which they probably need to cope with the platform width and I'm wondering how you will make the switch from a flat beam to a round (or eliptical) one later. Will you build the beam sockets for a round beam and use a semi-circular packer?

Are the hulls your own design?

Going wider has a real negative effect on platform stiffness. So the first F16's (Taipans) had to be stiffened up or they would walk over the waves far too much. The first F16's were hard to build down to minimum weight as the hulls are just significantly larger then the older Taipan. Part of the solution to both problems was found in using two 80x2 mm round tubes as beams. They are both significantly stiffer and lighter at the same time. Also this section is easy to get in most places, it is quite common.

Wouter

Yeah, pretty much just gonna plonk the current rig and beams on the new hulls. I have been debating putting a different forward beam on, but can't justify it at this point in time. The way I'm building the boat, I don't suspect it will be too hard to switch the beams over when converting to full size F16, with a little modification to the landings.

Yeah, it's my own design. A little bit radical, but nothing too far off what is currently out there. A lot of rocker, more freeboard than a mosquito (I HATE waves slamming into beams!), and narrow transom. Think a Hungry Tiger Moth crossed with a Taipan...maybe. Need to build new centreboards too, which I know will be more painful than the hulls, so I'm gonna look into some different designs there, they'll probably be the most radical part of the boat. Not canted or raked but probably assymetrical and gybing (like the 505). I'll see what the rules will allow and run some numbers before committing to that kind of stuff.

I won't be going wider at this point in time, no need to with my crew weight and rig size (don't need the extra righting moment). So the platform should be a little stiffer than the old ply mosquito of mine.

I've done a weight estimate and picked a laminate which should be suitable. Nothing extreme, simple foam and glass construction with strategic placement of a bit of carbon. I suspect the individual hulls to come in about 25-27kg (that number is relying on my memory so I will confirm later).

Future plans include carbon beams to full F16 width. I will take the leap of faith (and dollars) when it comes time to upgrade, they are well worth it in my opinion. Aluminium is becoming more expensive here in Australia, I haven't checked prices but I suspect by the time I get round to upgrading, carbon beams will be marginally more expensive than aluminium ones, but significantly stiffer. Although have said all that, the end connections will need to be looked at to take advantage of them.

What grade are those beams you're talking of Wouter?

Check out www.cstcomposites.com, also check out their adjustable spreaders, I'm going to order a set for my boat, instead of proctors, I'll have to make my own mast collar to suit is the difference. Carbon arms will be $50.00 cheaper than the proctor aluminium arms.
<img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />

Regards

hah, that's incredible, although last time I bought adjustable spreaders (aluminium) I was shocked at the price, and that was years ago.

Filament winding really has made these sorts of things cost effective. Certainly when compared with doing a mill run (a few tonnes) for small aluminium parts. Does anyone know if any company in Australia is doing composite pultrusion yet?

Nick,

what do you hope to achieve with assymetric gybing boards? And why gybing, why not put them in at eg a fixed 3-4deg angle?

I want to put assymetric boards in my own boat, but have been been warned not to do it as it just adds complexity without any speed gains from most experienced builders. A little minority say assymmetric boards are faster.
Main advantages are better lift while the hull tracks straight trough the water. Opening the slot a little bit as you point a little lower (or higher, for equal speed but going higher than boats with symetrical boards). Less wetted surface area. Disadvantages are handling of boards while tacking/gybing, and the need for two spares instead of just one. Finally, most tests I have head of on cats smaller than the C-class (which use assymetrical boards) have concluded that assymetrical boards are not faster.

Opinions?

I hope to achieve better race placings. This will be achieved with a faster VMG boat without adding too much complexity.

I'm just gonna look at all the options with the boards. I'm of the general opinion that there is a lot of thought put into the above water fluid dynamics, but not much with the below water fluid dynamics. Gains can be made.

If the boards can gybe, they won't need to be lifted between tacks, but will need to lift downwind. But either way, with self-tacking jibs becoming more popular, the crew has less to do during a tack or gybe so they can lift and drop boards easily. Where there's a will, there's a way.

There may be no benefit from all this at all, I'm just gonna look into it a bit. Boat handling requirements will always win out over a small speed improvement with me. I think someone said it in a previous post, but I'll rephrase it here, for every knot you are slower than a competitor, you will lose 0.5metres per second. If speed improvements are balanced against boat handling challenges with this in mind, improvements may be made.

This is a bit off topic, or even off forum. Unless the mosquito guys don't mind, PM me if you want to discuss more.

Just saw an add for mozzie parts in brisbane.
Tree fel on boat one hull damaged.
http://www.catsailor.net/
Its in the forum boats for sale.
May just get a few races in before the end of the season?

cant find it
You got the actual link for it

Not sure how.
Down the left hand side of the page there is a forum section click on that and scroll down to boats for sale.

Hey guys, Don't know where you are getting your proctor arms from but I can get them for under $ 300.
Regards
Chris Dean

Whatever a Proctor arm is, it must be pretty good for $300 !!!!

Hi Tim

You know the blue anodised arms that you can adjust, either on the beach, or with another type of adjuster barrel you can change them on the water, but this requires capsizing.

Goodalls asking nearly $400.00 for them, Binks I think work out to around $320.00 and everywhere else seems to be somewhere in between. The stainless steel mast collar may not be strong for cats and therefor most cats have a stronger one made for them, very easy, just a little bit more meat.

Regards

I might look into makeing some from carbon fibre.
May be cheaper.
I have a new mast to set up.

The standard proctor mast collar has been used on the Blade F18 and Hobie Tiger. I am not aware of any failures.

Chris

Hi Chris

Most Taipans and A Classes have a fitting made up by Goodalls, its not greatly different, but it is stronger. I think there were a couple of failures on the A's which made the decision for a slightly stronger bracket, I think the lug which holds the end of the adjuster barrel, is also a stainless steel fitting, which is stronger, also supplied through Goodalls.

Regards

still can't find it...

Got to www.catsailor.net
Top right click on Forum
Bottom of the forum page you will see for sale section and its in there

thanks, found it.