Seems from my experience and every video of DW foiling video I watch nowadays that everyone has a noisy tail to some degree. I've be sanding tails since 2019 using the 'Donaldson method ' and getting success on the older thicker tails without too much trouble, but the these newer thinner higher aspect tails have to be sanded to a razor edge for silence in my experience and become more of a safety risk than it's worth.
Anyone managed to achieve silence on the newer tails without making a razor out of them? And is there any wet and dry grade technique that works better ie ( 800-600 at leading edge and 400 grit towards the tail ?
Crisp 130 flex tail is silent.
Aussie designed and made.
Best tail I've used for my Armstrong setup to date.
Interesting ,I remember my KD Maui tails made out of g10 being fairly quiet too, maybe softer tails flex instead of vibrating .why do you like the new crisp tail over the current Army tails like 120,140 , I didn't like the unstable feeling that the old v200 flexy tail used to give
I asked Adrian Roper from Axis how to quieten a skinny tail that had a hum. Still work in progress but a huge amount better. Here was his advice
"Trailing edge too thick. Need to sand a bit off the bottom side and thin it out. Also square the edge once thinned out"
I have a KD13R (G10) that was a real screamer, after about 4 hits with the sandpaper it went quiet. Also just recently bought a new tail, been using a H125 or about 6 months, it's a little noisy but not enough to sand.the new tail is whisper quiet.
Maybe the higher aspect are harder to tame?
Select to expand quotebaldy123 said..
Crisp 130 flex tail is silent.
Aussie designed and made.
Best tail I've used for my Armstrong setup to date.
Yep mine is awesome too and quiet. Not as quiet as my chopped AFS tail though. OP could try a chop. Took 30mm off each side of the HA tail much quieter 
Select to expand quotetoppleover said..
I have a KD13R (G10) that was a real screamer, after about 4 hits with the sandpaper it went quiet. Also just recently bought a new tail, been using a H125 or about 6 months, it's a little noisy but not enough to sand.the new tail is whisper quiet.
Maybe the higher aspect are harder to tame?
Yeh , that's been my experience too the higher aspect thinner ones, It's probably the thin tips vibration as hilly found chopping them off silenced his.
A friend was talking to Adrian Roper and asked about the whistling tails. He said "Listen to the Americas Cup hydrofoils. They scream."
If 'those guys' are OK with humming foils and have nearly unlimited resources to optimize for speed and efficiency maybe we should be OK with a little whistle.
PS: What is the objective:
1) To just make the tail silent
2) To increase speed of the entire rig
3) ? ? ?
The tails shown about appear enormous. I was skeptical of the tiny tails but have dropped from a 210 cm^2 tail to 105 cm^2 tail, 50% the size. Eliminating the hum would be nice but pales in comparison to what you feel when you cut your tail size in half.
Beasho the objectives for me are :
1. Efficiency... ( I'm in 60s and DW paddling and want every scrap of help I can get and noise is inefficient )
2. Stealthy... ( I've been chased by an angry mother whale and her calf and my mates's board was hit by a shark immediately after dropping off foil)
3. Understanding..(Have been able to make some tails silent but not others)
4. Superiority and Ridicule...( I want to be able to pay out on my mates on other noisy gear 
)
Hey Kobo, You have most probably seen this already but for those who have not..
www.instagram.com/reel/DLXPTnnztmv/?igsh=MTJqdnc1am0xMjY3NQ==
Select to expand quotetoppleover said..
Hey Kobo, You have most probably seen this already but for those who have not..
www.instagram.com/reel/DLXPTnnztmv/?igsh=MTJqdnc1am0xMjY3NQ==
This is a Donaldson.
Select to expand quoteairsail said..
I asked Adrian Roper from Axis how to quieten a skinny tail that had a hum. Still work in progress but a huge amount better. Here was his advice
"Trailing edge too thick. Need to sand a bit off the bottom side and thin it out. Also square the edge once thinned out"
In other words, a Donaldson.
Select to expand quotekobo said..
I've be sanding tails since 2019 using the 'Donaldson method ' and getting success on the older thicker tails without too much trouble, but the these newer thinner higher aspect tails
You may want to create a "mold".I found a "sanding block" for fins in a surf shop a long time ago that was basically a sanding stone (like for knives) but with grooves with the proper shape for the leading and trailing edges.
I guess you could make one for Donaldsons with a stone with grooves with round bottoms that you would fill halfways with resin or a wood piece to only get a half round.
