Mast weight and rightability

would you cnc the female mold or cnc a male plug and pull a female mold?
If the first what would you consider to be the base cnc material?

Years ago I tried to do this but the foam manufacturers here couldn't make me a foam block big enough to form a skiff mold..

Stewart, everything goes to plan it will be straight to female moulds using a

tooling board

type product with or without a tooling paste. We're doing some test parts (F12 foil moulds) in a couple of weeks. The ability to machine 3D shapes is a bonus feature on the new router that my client has just aquired and we hope to use it to make moulds for composite cabin tops on his existing aluminium hull designs.

well I learn something every day!!

So why didn't you tell me about this 15 years ago!! Looks like for limited run one can even use it for prepreg!! Thanks really useful info..

Anyone want to build a skiff? I have a design ready to go! <img src=

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Nope, but if you have something to build an A cat the thing is different <img src=

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A cat? hmm.. Sorry no and Im not a good enough designer to give you one that would be more than a dog..

However I grew up building skiffs so well aware of the wedge hull platform.. A few pieces of ply at the start of winter and you had a skiff by the season opening.. Especially Cherubs were the kids winter projects around here.. This is where Murray and Bethwaite learnt their trade.. If it didnt perform there was always next winter!! It was an exciting time to grow up..

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Well, I am coming from mono hulls so maybe, but now we are off topic...

Also it would be interesting to know if that was the case with lighter mast because (harsh generalization) slapping over 2 kg's to mast requires more than 5 kg's of skipper weight. Let's keep in mind that righting might be ordered when there is no wind and thus skipper would violating rule 1.9.1 even though in normal windy conditions righting would succeed (I do believe in righting in all conditions because it makes boat safer).

Best solution would be that manufacturer measures them, somebody should be doing that quality control wise anyway. If that's not possible then data from every boat measured should be made available somehow. That way people could be making their decisions based on real data.

Wouter mentioned something about China... Hopefully somebody has not been that “stupid”...

for fear of throwing fuel on the flames.

Formula cat, Vector etc get what they are given by AHPC. I doubt they have any choice in the masts they receive. When Boyer was heavily involved the quality control seemed much higher.. Hopefully this will improve as the new factories get more experience.. As for where the masts now are extruded I am not 100% sure.. The only person who would know is Greg Goodall.. Whether he will tell is another issue.. Saying this his sails still seem to be showing the way and that division seems stable...

I do know that Chinese extruders are not guaranteeing a straight tube under 2 mm wall thickness.. This may be where your getting the chinese reference.. This basically leaves the vast majority of Chinese extruders unacceptable for us to use.. Saying this there may be a factory in China who has the technology & skill to do the job.. But finding the gem inside the box of dross isn't an easy task unless you willing to spend a few months in China and paying a trusted chinese associate to walk you through the process..

Guys I know his isn't satisfactory but please be calm.. There are two avenues of exploratory investigation happening to improve the situation.. One or both could come up trumps with something for the F16 population.. We just have to give the boffins time to work the numbers.. Remember these guys are doing the work for us for free.. Even if it goes ahead they will only just return their costs without labour costs.. So we cant place too much stress on them to finalise the research unless we pay...

My only suggestion is contact Stealth and get a current bare bones stick quote.. If your desperate for a stick asap and do not trust the recent superwing batches. Or contact Scarcrow and get plans for his ply/carbon wing.. <img src=

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But if your a Viper

one design

owner I guess your stuck.. <img src=

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The first ply/carbon wing for homebuilders designed by Scarecrow are under construction <img src=

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Valterri,

Well the simple reason is that this info (which is not yet determined to be true over the full range of masts) was not

general knowledge

till your story appeared. I for one did not know it.

I simply can not advice you or make general knowlegde something that I don't know myself. Also I have no indication that AHPC was aware of the variation themselves.

Again, your 2 masts are the most heavy supering masts I have ever encountered. Interestingly enough I have measurement data on a mast bought last year that is below 15 kg for the bare section. It is
almost certainly from the same batch as your mast. I remember that your first claims were that the bare mast weight was 19 kg's although you have already adjusted that down to 18 kg now ; incl downhaul and fitting ex spreaders.

I told you a million times already, the measured data I have on about 15+ mast does not conform well to your data. Now indeed I don't go over to the extrusion plant and measure all masts for compliance myself, sorry !

You are grasping at straws and starting unfounded rumours all over the place.

There are no 2 dies, we didn't know about the variation in your mast, our measurements of a subset of the complete batches do not comply well with your measurements, there is no indication AHPC knowns about this and we have not encountered this problem before. We have weighted slightly heavier masts but nowhere near to your measurements.

Now, I understand that you are unhappy with a mast that is several kg heavier then it is supposed to (and that other young masts are); I think you have a right to be. But you are trying to make it into a situation were you have been intentionally deceived by a group of people which is simply not the case.

Wouter

It is interesting to note where some of the cat builders are getting their beam and masts extrusion from.

Our Superwing mast however do not come from China.

Wouter

Several people in the F16 class know the details but are bound to some limitations set out in the agreement.

Wouter

They must have because I have two off cuts here, one from my mast and one from a sloop section and the cat section is physically smaller than the other, not just in wall thickness, if for example I cut the mast track off the cat section it would fit inside the main body of the sloop mast.

This could be the explanation, the flaw in the soup is that somes are still saying that the weights of the new spars correspond to the old cat spar and not the sloop spar if I understand the things right.
Do you have any idea of how big the difference is, maybe some Taipan guys have had the mast on the scales as they seems to be aware of the difference.

Matt,
That is not consistent with my understanding.

Are you sure that you are not comparing the masts
used by AHPC on the T4.9 and T5.7. because the T4.9
would fit inside the T5.7 mast if the track was cut off.
Also the original Aussie wing (extruded to avoid importing Sori wing mast from Italy for A class) would fit inside the T4.9 mast.
A quick measurement of the major and minor axis would
tell the story.

Regards,
Phill

The cat rigged mast section is 145mm x 59mm and what I thought or think is the sloop is 150mm x 62mm.

My apologies if I'm mistaken, but thats what I was lead believe the bigger section was - the sloop section.

Regards

Matt,
That is interesting.
I've not come across the 145x59 section before.
The other one is the standard section.
My understanding is the same as Wouter's in as much as there were some cat rigged sections but likewise I was of the understanding the only difference was wall thickness.
Unfortunately I have never actually measured one to confirm.

Regards,
Phill

I sent an email to AHPC about this, hopefully they'll have an answer.

And to Wouter I have to say that my error margin with bathroom scales is three times smaller that actual mast weight difference that came out wearing die (which is acceptable by you), ínternal DH and mast foot has always been included in both numbers (and said so). Also now that mast was re-measured it was totally dry, previously it could have easily have some ice attached here and there even though it looked not to be the case.

All I'm getting at that we have different masts here in Finland than rest of the guy's out there (15+ measurements) and you don't believe that it is the case and thus your are trying to question my reliability or you try to say that there is no difference. Why is that so, are you personally involved somehow to this whole issue?

Well, we have a difference in wall thickness here it should be around 1,6mm and we have two spars here (in fact three the damaged one is the same) at 1,85mm and there must be some more of those on the market, don’t know how many spars coming out of a batch.

Gday Phill

Saw the Blades at Portland. Very Nice.

I bought the section from Darren Peters in Adelaide, you may know of him, he advertised it as the original cat rig section and bought it as a spare, when he sailed Taipans, from my understanding he too built good hulls and was up near the top of the list, thats all the info I have.

When I bought the hound fitting from AHPC, it took me a while to reform it to my mast section.

Regards

Maybe but its Greg's decision what info is released on his business.. We must respect that... <img src=

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If I understood the posts of phill and mattaipan right the profile of the AHPC Superwing is 150x62mm. Can somebody confirm that please?

I have not been reading this whole thread but why would you want to be able to right your boat in any condition? <img src=

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IMHO if you go over in anything under 10-15kts maybe you should consider staying on the beach or something <img src=

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And if you want 100% certainty that you can right in any conditions maybe you should have spent some more cash and bought the light carbon mast instead. <img src=

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From F16 class rules:

1.9 Minimum weight of the crew

1.9.1 There will be no other restrictions on crew weight apart from the requirement that the crew weight must be sufficient to right the boat unaided under all encountered sailing conditions.

So boat should be rightable in light/no wind or rules are violated intentionally (in my case).

Aren't you taking things a little to literally?
Just take one of these ultra light weight

righting devices

with you and you will be able to right in any condition:

No Valtteri,

The rules only stipulate that each F16 boat must be fitted with a righting system that allows the crew sailing the boat in a sanctioned F16 event to right it in all conditions unaided.

You are constantly refusing to look at the righting alternatives. Which are righting poles , righting bags, shroud extenders, Gary's solo right system and several other setups.

A righting bag is the most simple and cheap alternative that will work for very lightweight solo crews on the F16. That system alone has several different setups.

The use of the single righting line is only one way to right a boat. One that will actually work for your 75 kg for winds above what ? 10 knots. So you only need to use an alternative system like the bag for the times you flip the boat in light winds days ?

I think you have a point where the mast is heavier then it really should be, and we are working on that, but for the remainer, aren't you a little bit over critical ?

Wouter

I can although I measure 150 by 62.5 mm

I think AHPC quotes it as 150x63 mm

Wouter

Thanks, just don't want to mix the things up