Performance v durability.....

I can appreciate the lighter the better for performance for downwind foiling but at what expense for the durability/longevity?

To give you a background, I have been surfing, windsurfing, kiting, kite foiling, SUP surfing, wind winging and now downwind foiling for the past 37 years (yeah, that reads old bloke..) but have never experienced board failure like this.

So, as the average punter, bought a well known brand that is no more than 6 months old that I have already repaired 3 times and noticed yet another crack. All cracks are on the bottom rail and in different places. Problem is, there is no evidence of strike damage eg paddle or depressions. You know when you have f**ked up and you take ownership. The laminate is that thin I reckon it took just as long to sand through the paint/undercoat as the carbon.

Purpose of my post....nothing but a vent before I drop yet another few grand on a what is now a well researched, durable board!

Yeah, did all that but it's not a defect in the build rather than light weight construction.

Apologies for the rant, it doesn't achieve anything, just frustrated (and don't post after a few beers....)

I was curious if anyone else has had a similar experience.

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Capt.Gumby said..
Yeah, did all that but it's not a defect in the build rather than light weight construction.

Apologies for the rant, it doesn't achieve anything, just frustrated (and don't post after a few beers....)

I was curious if anyone else has had a similar experience.

I'm at the experience with 7 failed production foil boards that it's fair to say that if it says made in China on the box, there is a 100% chance of defect and/or quick failure. This forum has become quite pc in not naming names, which I suppose is fair as I'm sure like autos, the majority of buyers are satisfied... but I don't think lightness is the entire issue. Cost is also the problem. In the states a name brand surf longboard goes for about $1800 usd and consists of very little labor and cheap materials compared to a vacuum bagged carbon and eps foil board that also retails for that price. Figure a production foil board has the factory cost, shipping, then distributor markup, shipping again, then retail mark up. It's marketed as an advanced composite construction with a name recognized in the windsurf/kite industry so we asume it's built to take abuse and has a warranty... try taking your waterlogged, spyder cracked, heel dented, 6 month old 9'4" longboard back to the surf shop and demand a warranty replacement!

I bet if you asked Appletree to make a reasonably light board that was 4'8" and indestructible, they'd say, "sure, no problem" but if you said you want an 8' board at under 12lbs with the same durability they'd politely show you the door. It's not to say China can't make a board as well built as say Kinetic or Appletree, I just think with limited production runs before the next shape variant, and the extremely small margin to the factory and nature of the contract job, there's going to be lots of little things like over sanding, cheap inserts, improper laps, etc. that are hidden under the paint and filler and not qc'd. And unlike Kinetic, Appletree, and Cobra who care about their factory name reputations, are willing to manufacture boards to a spec that's not strong enough. Lastly, because they're so cheap to the purchaser, brand X isn't overly worried if a few get replaced before the 6 month warranty is up.

Check this video and note Mark says this board was 10.2 lbs. Remembering that carbon is much heavier than glass, imagine weight wise if you almost doubled the materials as would be needed for an 8' downwind board. Imagine if you offered him $400 for each board!

So the point is: light and strong = well built = $. And even if it's a better built one, it's still a surfboard that you'll end up doing something stupid like dropping your foil mast onto

Now that's how you rant.

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Hwy1North said..
Remembering that carbon is much heavier than glass

No, carbon is actually a bit lighter than glass, about 15%.

For boards also, time is money.
For instance, glassing layer per layer with curing and sanding between each layer will give you a stronger AND lighter board than just glassing all the layers at once. But it will consume a LOT of time, and thus will cost more. There is no free lunch. My custom Gong boards were twice the price of my production Gong boards, but their strength/weigh ratio is worth it.

Chinese factories can produce quality boards, BUT:
- their customer (the brand ordering the boards) must pay for the extra time
- they must pay a decent wage for the glasser and sander to secure people with expertise and experience. And these people are a limited resource, a really hard problem for large productions.
Alas, a lot of brands that use Chinese factories are not ready for this... nor their customers.

As an example, Gong just said that to produce enough wing sails for the summer, they employ (indirectly) 600 seamstresses / seamsters paid each 2300 to 3800 AUD / month.

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colas said..

Hwy1North said..
Remembering that carbon is much heavier than glass

No, carbon is actually a bit lighter than glass, about 15%.

For boards also, time is money.
For instance, glassing layer per layer with curing and sanding between each layer will give you a stronger AND lighter board than just glassing all the layers at once. But it will consume a LOT of time, and thus will cost more. There is no free lunch. My custom Gong boards were twice the price of my production Gong boards, but their strength/weigh ratio is worth it.

Chinese factories can produce quality boards, BUT:
- their customer (the brand ordering the boards) must pay for the extra time
- they must pay a decent wage for the glasser and sander to secure people with expertise and experience. And these people are a limited resource, a really hard problem for large productions.
Alas, a lot of brands that use Chinese factories are not ready for this... nor their customers.

As an example, Gong just said that to produce enough wing sails for the summer, they employ (indirectly) 600 seamstresses / seamsters paid each 2300 to 3800 AUD / month.

All true.

My reasoning for "carbon is heavier than glass" in a board laminate is that it is thicker per weight in terms of the weave and will hold more resin, especially with two layers. I suspect your typical light production DW board is one layer of carbon 200gsm (6oz) and one layer of 4oz glass with a second layer of carbon under the deck pad area, along with filler for sanding.

If your board is using spread-tow carbon cloth of equal weight to fiberglass, and properly vacuum bagged, then I stand corrected as the carbon fiber is lighter and there wont be any more resin used.

The Flying Dutchman is an artisan extraordinaire.

In this video he introduces what I call the Hectoliter Factor. The standard is 10 lbs per 100 liters.

HL = 10.0 is like shooting Par in Golf. It is the standard by which people should measure "performance" for downwind boards.

Above 10.0 is evidence of compromised performance and construction.

Note: This applies to downwind boards. Winging boards may have to be a bit more robust.

.be

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Beasho said..

There is so much wrong with this graph.

For one, the carbon fiber selected appears to be ultra-high modulus, which has **** strength. It is very common to find medium modulus carbon (still much stiffer than S-Glass) with strength well above S-Glass.

And, you want ultimate tensile strength divided by density which strength to weight. S-Glass absolutely doesn't have an edge on carbon on strength to weight.

The only place you'll find S-Glass with an advantage depending on exactly which carbon fiber is selected is in strain to failure (damage tolerance). The other place S-Glass has an edge is in making springs. Somewhat surprisingly, lower modulus and large strain to failure is really helpful for making lightweight springs. The lightest leaf springs (for their energy storage capability) utilize S-Glass.

If you're hell bent on making the lightest board possible. Why don't you just make a hollow carbon board?
There is a fair amount of lost weight you're keeping with that foam core! Could easily shave down 1kg if not more!

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Beasho said..

Pacoo said..

paul.j said..
Yeah there so much to it all but also so much crap getting sold to customers it's crazy.

If the board is fragile and a company blames the weight then it had better be bloody light. As an example for a DW board they say for 100L is light and it's over 6kg then the board is just ****. If it's in the 4kg range then this is what I would class as the lighter side. . . . driving the construction down so far it's embarrassing.

Fully agree, some brands justifying poor construction and manufacturing control with the label "light". Anything over 5,5 kg is out of the market for me after 4 years of supfoil. Any company selling boards over 7 kg is slowing down the sport.

I would consider 3.5 kg / 100 Liters "light". Why? Because the very first homemade board I built was 3.45 kg / 100 liters.

I was wondering if this was an anomaly, and was happy if the board only lasted 30 session, but 189 sessions later after I learned to downwind, flat water paddle up, no-wind downwind, ride tiny waves and catch waves up to 10 feet, the Sailfish is still working. I only replaced it because I wanted a slightly better shape. Most people may never get 189 sessions out of a board.

Here was the replacement: 8' 8" x 19" @ 129 liters 4.9 kg (3.8 kg / 100 liters) Orange Crush.

Does performance & weight matter???? I have 30 sessions on the Orange Crush ~ 300 waves and in 4 weeks have only missed 5 takeoffs. This includes flat water attempts, downwind attempts and SUP foiling. That's ~ 1 miss out of every 60 attempts. At 54 years old, slightly heavier than I want to be (85 kilos), I can takeoff every time I want to barring some random wobble or twist.

Comparison of homebuilt 'performance' vs production boards.

Yeah I was also been pretty genouerous with my weights on what should be light.
I just finished a custom which is 120L and came in at 4.6kg including pad. I am by no means a master board builder and love learning new things all the time so great to see all your info.
For DW boards they can definitely be built pretty light and even my latest prone board that Made for my self only came in at 2kg with full pad and feels sweet being so light.
But saying all that i would definitely want one of my PVC sandwich boards if I was learning or really rough on gear as they are bombproof in the board world.

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King Crash said..
If you're hell bent on making the lightest board possible. Why don't you just make a hollow carbon board?

If you make a hollow board, you must then reinforce the deck so that it does not collapse.
Plus you need a mold, quite more expensive than a mere foam blank.

It is tricky to design reinforcements that do not end heavier than a foam blank.

My opinion is that the solution could be either a multi-density blank (lighter at the core), or drilling longitudinal holes inside the blank.

My dream would be to train (or bioengineer) bees to build custom "real" honeycomb blanks.

Beasho - I'm wandering into the theoretical when what really matters is the practical. We both know that. But still important to get the fundamentals correct, which is why I'm replying.The problem with the graph is "High Tenacity Carbon". That term is not a real term, so I have no idea what kind of carbon fiber they are referring to. This is a BAD BAD BAD video. The person makes claims of knowledge, but is just plain incorrect. Carbon fibers come in a wide range of stiffness values, with differing strengths. The person making the video either doesn't know that, or is purposely cooking the numbers to make a controversial (and generally incorrect) point.

The numbers presented for strength and stiffness of carbon fiber are not at all representative of what is typically used.BUT, I can tell you that the carbon fiber cloth we use to make boards has a similar strength to S-Glass, resulting in higher strength to weight ratio based on density. It is also much much stiffer. Agreed, all forms of carbon fiber composites that I know of generally have less capability to withstand damage if the same epoxy is used! Fiberglass gets a bad name in part because it is often used with lower cost resins that give the resulting layup poor mechanical properties. For the right applications it is the best known material choice.

I tabulated some numbers below, to get some better detail on the various general categories of carbon fibers. The stiffness differences are really quite amazing - thus why a lot of people are using carbon. Most hobby builders are using Standard Modulus Carbon, but Intermediate Modulus is obtainable.

S-Glass
Modulus of elasticity (Stiffness): 89 GPa (12,910 ksi)
Tensile strength: 4,600 MPa (670 ksi)

Standard Modulus Carbon Fiber
~3X stiffness, similar Tensile Strength

Intermediate Modulus Carbon Fiber
~4X stiffness, 1.2-1.5X Tensile Strength

High Modulus Carbon Fiber
~5X stiffness, similar Tensile Strength

Ultra High Modulus
~9X stiffer, 0.6X Tensile Strength

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broVan said..
What are foamies made with? Seems to me that, kind of like an inflatable, we only need real stiffness from foot to foot, and the tip and tail could be "foamie stiffness". Just enough stiffness to keep shape while paddling and takeoff. Once up, it just needs to be stiff under pilot. I have been kicking around the idea of a DW board with inflatable nose and tail that could be deflated upon liftoff. My home built board gets dinged if I look at it too long.

What about a carbon top plate like the Starboard inflatable DW board attached to a foamy hull? Could just replace the hull when it eventually goes mushy.

sounds like a warranty to me ...

With performance vs durability:

1) Hollow boards don't add up. Too much weight in the skin infrastructure, sandwich construction, expense for molds and it's not been proven

2) EPS boards run the risk of 10,000 dings. Any one of which can load the board with water. I have boards that are 15 years old that still look great but everyone of them is heavier than when I bought them. They all eventually leak and take on weight.

3) I have proposed XPS builds. Proven them lighter than anything on the planet. Built 4 of them and they all weigh the same as they did when I built them 350 cumulative sessions later. But people complain that they don't look good enough to sell. ?

So turn the question around. How do you define "Durability?"

- What do you want from a board?
- Do you want it to look as good 30 years from now as when it was new?

I have some Sandwich windsurfers that still look great. But the sun set on my desire to ride a windsurfer 20 years ago. How much should planned obsolescence play into the Performance vs. Durability debate? Is the question really Looks vs Performance vs Durability?

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colas said..

Beasho, how did you solve the problem some shapers had with XPS, that is delamination by air bubbles acting as wedges between the foam and the lamination?

Pinholes. You leave the fiber porous. Meaning don't fill the pinholes. A single lamination layer, 3.7 oz S-Glass for example, will have 100's if not 1000's of pinholes. So you DO NOT Hot Coat, DO NOT Gloss coat, nor add kilos of hard candy shell to make the board waterproof. No need.

My last board I sanded the bottom S-Glass lightly and then spray painted. No Auto Body finish. Those good looks kill the performance by adding 3-5 lbs of weight.