Alright,
There are two ways about this. You can either put your faith with the engineers and designers like Phill, Jennifer, John and Myself (I count the other class heads as valuable members of a different stripe. And trust that we 7 class officials make the right choice. OR you can try to understand the issue as best as you can and lets your opinion be know.
I will now continue with the second approach :
Just in plan and simple understandable English, Preferably in lbs. instead of kg. too.
F16 class rules specify that all values must be expressed in SI (International system) units. Seconds, meter, kilograms. But I will put conversions into brackets. But it is time that the two nations left in the world convert to SI units as the other 178 nations have done. I know its origin is French BUT it does really work better than "3 feet in a yard, 12 inches in a feet, how many in mile ?". Sorry just a pet topic of mine.
Anyways.
1. I understand there is a difference in the overall weight of the Aluminum Superwing Masts and the CF masts.
Correct, but teh difference can be less so than when looking at density numbers. Simply because other constraints like minimimum wallthickness limit the weight savings. Note that weight savings in itself don't help you under F16 rules because of the overall minimum boat weight. You can only reinvest the saved kilograms.
2. It also seems from the discussion that some of this equilibrates once you add hardware to the mast, since for some reason unknown to me the CF mast hardware must have to weigh more than the Aluminum Mast Fittings.
There is no reason why carbon mast fittings HAVE to weight more. At least not enough to make a significant difference in overall weight or tip weight. They fact that some carbon mast do have heavier parts has to do with choices made by its designer. Ease of building can be one of the driving factors. Of course relatively speaking the fittings make up a larger part of the total weight when looking at a carbon mast that is because the weight of fittings don't change while the section becomes lighter. Ergo they make up a larger percentage of the total. But this is different then what you say.
3. You don't want to alienate a group of Cats already built which can meet Class specs with a weight compensator. We do that in all the Formula classes to allow for variations in crew and boat weight, No one has come up with a better solution yet that I'm aware of.
This is not a question but a statement. I would like to add : We, as a class, don't want to write the rules in such a way that we favour the Alu mast over all alternatives or the other waya round. We wish to allow maximum freedom of design without risking significant difference in all-out performance. Equal performance ON THE WATER is paramount not equal performance in mathematical models or under laboratory conditions.
4. It seems if you only drop a small amount off the current weight tip requirements you can still accommodate these underweight-masted boats within class regs. (sounds reasonable, I can't vote on this not yet being an owner, but I still have my opinion about keeping things simple so the most people can participate in a class on equivalent terms)
Only the doublehanders. The specilized single handers are probably out of luck. The "good will" stops somewhere. But we probably get the biggest group included this way AND we keep some margin of superiority with our closest competitors. The added weights to the guys falling outside of the rule is still limited enough to not hurt them. In all honestly the 6.5 kg tipweight rule will work but the 6.0 kg tipweight rule will work slighlty better. After this the rules will be fixed for years to come so I want to be sure that we don't regret the compromise that we reach.
Also we let it be known that after this will be BAN any crew from racing when his mast is found to be underweight with respect to the tipweight rule. We hold the builders responsible for any failings in this area. No more pardonning.
5. There is some argument that soon CF Masts will be as durable as Aluminum. I'l like to know how to splice a CF mast or weld a crack or hole. My take on that is that You can Repair Aluminum, you basically can't fix a CF mast, and the CF masts are more prone to failure. For Example, My 1999 Inter 20 is on mast #3, that equals < 2 years on a CF mast. Our other 1999 Fleet I-20 had so much wear and Degradation to the Mast, I was amazed we got it through the Tybee500. CF MAsts have to be treated with extreme TLC, or they get wear spots and Weak spots. CF is also prone to Failure due to UV degradation. So we are supposed to keep our masts out of the sun to avoid this. What's up with that on a beachcat? Are we only going to go nightsailing?
Actually what you are pointing out to us is that carbon mast are NOT preferable in all aspects. Something that most sailors simply forget. There are some noteworthy drawbacks of carbon masts. And their are some noteworthy advantages of alu mast. One of this things is the extended adjustment range of alu masts. This is to be prefered on boats that are used frequently in both singlehanded and doublehanded sailing. I will say the following only once, so take note, I will personally not switch from my current alu to carbon even if I can do that for free. The alu suits my way of using/racing the boat better. And as a added bonus I don't worry about leaving it standing on the boat or UV degradation.
6. Some discussion that CF is going to be cheaper than Aluminum: Even the Implication that there will not be a supply of Aluminum masts to the Manufacturers. (Is there some projected world shortage of Aluminum that I'm not aware of? MAybe we should all go out and collect aluminum scrap so we can melt it down for our future masts)
These are mostly scare tactics, brought into the world among others by the Tornado class and Marstrom to force a yes-vote on the carbon rigs. My personally experience is, and I worked the superwing mast deal for the last 3 years now, is that there is NO problem with supply OR cost of alu masts. We don't expect any to develop in the near future. On the other hand a greater urban legend is the fact that carbon is expensive. It is indeed MORE expensive THAN alu in as good as all instances like poles or booms and masts but that doesn't make it expensive outright. It is not even near to as expensive as Marstrom and some carbon mast builders make you believe. I will have to suffice with a simple example : I could order a carbon mast blank at Stealth Marine for 750 UK pounds = 1085 Euro's; My superwing at that time came in at 880 Euro's. Both for bare sections and including taxes; profit margins; the works. Seriously those 300 Euro's is peanuts on a whole boat. The fact that mast builders request between between 1700 and 3000 Euro's for bare sections (Hall spar even more I believe) has everything to do with profit margins and earning back development costs. With respect to the last point it must not be forgotten that the design and making a NEW alu mast creates about equal development costs.
Take from this that alu mast sections are still cheaper than carbon mast sections (the fittings are of course the same) but the difference between the two in REAL cost (no profit difference or develop cost differences etc) is less than 300 Euro's. To give a nice comparison I think alu Hobie 16 masts are more expensive than Stealths Carbon mast. We must take great care to seperate the myth from the fact. So it is wrong to just say carbon is always more expensive than alu. This dependents entirely on who is selling you the mast.
One more thing; currently we don't expect any carbon mast development from the Taipan and Blade builders as none of these see the (ASSUMED) potential benefits outweighting the required investments in time and tooling in any significant way. That Superwing alu mast is really regarded as a difficult benchmark to beat already. Only really pressing reasons can change that and pretty much only political or perception reasons can scale up to that as any performance reasons are just too insignificant. In some cases performance reasons may well even favour the aluminium. Again don't fall for the myth.
7. Finally: We talk about the relative righting advantages of the CF Mast, but the Compensating weight we put on the Tip of this Lightweight Mast Is going to add all the weight to the top of the mast which is according to my rudimentary understanding of physics, going to magnify the lifting (righting) energy required by the distance(mast height) x counterweight mass. All this will increase the righting difficulty even more than having this same weight evenly distributed along the length of an aluminum mast.
There is some core of truth in what you say but you are still wrong. The way the tipweight rule is currently written does NEVER increase righting past the level of the theoretical lighest allowed F16 mast. This level is curently at 62 kg ( = 137 lbs) with 6.5 kg tipweight and will be at a shy 57 kg (= 125 lbs) with a possibly new 6.0 kg min tipweight rule.
Say a mast is underweight AT THE TIP, say 5.0 tipweight, than adding 1 kg to the tip will end up with a mast that can be righted with 57 kg's on the righting line ; just as the min theoretical allowed F16 mast. So we don't hurt anyone in righting, we do make it unattractive to intentionally build underweight masts as you can not gain any righting advantage with it.
NOTE : take my word as an engineer. Adding (more) weight along the mast to make this 5.0 kg mast have a tipweight of min. allowed 6.0 kg WILL NOT MAKE ANY DIFFERENCE in righting with respect to adding (less) weight to the tip of mast to end up at the same 6.0 kg.
Take good note of that. Things are a little different when looking at dive recovery and swinging about but not in the case of righting.
It should have the same magnification of effect (Distance x mass) since it is positioned at the end of the stick as the inertia of the counterweighted mast tip waves wildly 30 feet in the air.
This does not factor in in the way your present it with regard to righting. But is an explanation why a 6.5 kg tip weight on say an I17R (if it is goes that low) that has a taller mast, IS MORE DIFFICULT to right than 6.5 kg at the top of an F16 mast. (Difference in such a case would be 4 kg's in sailor body weight)
8. Someone please, help me, I'm into Wouterspeak here.
Who better to help you than Wouter Himself !
Or is that a contradiction ?
One more thing though.
The talk you had about the difference in distribution of weight along the mast does factor in with repect to dive recovery and swinging about in waves. However because we have limited mast height to 8.5 mtr. the depencdency has been severaly limited (note this difference between us and the A-cats ! It is an important one !). I won't go into detail as that will require more in depth knowlegde of scientic and engineering principles.
By this interaction between two F16 class rules we end up with a situation where a tipweight rule WILL penalize underweight masts by making them less efficient in dive recovery and swinging than the min allowed theoretical mast HOWEVER only PROPORTIONALLY to the amount of being underweight ! This is a great way of allowing freedom and still force compliance with the rule set. Simply put
-1- You are only disadvantaging yourself by having an underweight mast; so why do it ?
-2- You are only penalized proportional to your magnitude of your non-compliance so if you are underweight by a neglectable amount due to some quality control issue than your disadvantage is equally neglectable.
With both the 6.5 or 6.0 tipweight compromises the Alu superwing is still very close to the optimal rig to make any POSSIBLE differences in performance negelectable. These may go EITHER way as alu has some sweet spots as well ! This is because we need to add the contributions and behaviour of sails etc to make a proper comparison. Any MAXIMUM differences are prejected at a fraction of 1 % and as said earlier is to be compared to buying a new jib every year. If you buy a new mainsail as well than you will have gained a multitude of gain. This is the order of things we are currently talking about. AND AGAIN, the advantage may well fall either way. Proper mast design is so important that an alu mast section can be just easily better than the carbon mast as the other way around.
I hope this helps,
Wouter
