Nothing worse that trying to accelerate with even small weed on the fin.Sometimes we are not aware the fin is not totally free of debris,.
Here comes my another invention ( made some times already but never implemented ( as usual for me))Lets imbed into the fin structure single or two conductor wires.
Wires extended onto the top of the fin and Connect to the control box.Control box contain small electronic circuit detecting capacitance on the wire ( or any other electromagnetic phenomena) that do change once a small piece of weed is attached to the fin.Then small piezo buzzed make a short beeps to remind you about weed problem. I imagine that electronic control box could be add on, independent device of the fin itself or even board, attached on request when needed. Fins to work with detector must be specially prepared- by imbedding conductor or spraying , painting conducting path along.As to exact method of detecting weed on the fin , we need go back to electronic laboratory, check capacitance, ultrasound, magnetic properties/ inducting. Wires or no wires technology to synchronize fin with control box.

I think that our guy that did our motion gps will good start to implement idea.

then completely different problem is what to do once you know that weed is on the fin:
- can we shake it off?
- need to stop and remove manually ?
anything else? but for sure racing or speeding doesn't make much sense with weed attached..we know that weed fin is the easiest , first anwer, but that is compromise not to be easy accepted by all.

Make the wire burn the weed thru/off.

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Macroscien said..
Nothing worse that trying to accelerate with even small weed on the fin.Sometimes we are not aware the fin is not totally free of debris,.
Here comes my another invention ( made some times already but never implemented ( as usual for me))Lets imbed into the fin structure single or two conductor wires.
Wires extended onto the top of the fin and Connect to the control box.Control box contain small electronic circuit detecting capacitance on the wire ( or any other electromagnetic phenomena) that do change once a small piece of weed is attached to the fin.Then small piezo buzzed make a short beeps to remind you about weed problem. I imagine that electronic control box could be add on, independent device of the fin itself or even board, attached on request when needed. Fins to work with detector must be specially prepared- by imbedding conductor or spraying , painting conducting path along.As to exact method of detecting weed on the fin , we need go back to electronic laboratory, check capacitance, ultrasound, magnetic properties/ inducting. Wires or no wires technology to synchronize fin with control box.

I think that our guy that did our motion gps will good start to implement idea.

Mmmmmmmm No.
1 extra drag from wire2 something extra for weed to wrap around

3 the vibration noise from the wire

4 damage to the fin from the wire slapping at it

5 you can feel weed on your fin if you care to listen

6 to get weed off chop jump or spin the board sideways, takes 5 secs.

Try this for an idea. A shrinking fin...starts out as a 32 and the faster you go the smaller it gets. A retractable one won't work as there is too much drag from the slot. A changing angle might

Retacting fin is a great concept. How about make the slot into a Fangy Fillet.

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kato said..

Macroscien said..
Nothing worse that trying to accelerate with even small weed on the fin.Sometimes we are not aware the fin is not totally free of debris,.
Here comes my another invention ( made some times already but never implemented ( as usual for me))Lets imbed into the fin structure single or two conductor wires.
Wires extended onto the top of the fin and Connect to the control box.Control box contain small electronic circuit detecting capacitance on the wire ( or any other electromagnetic phenomena) that do change once a small piece of weed is attached to the fin.Then small piezo buzzed make a short beeps to remind you about weed problem. I imagine that electronic control box could be add on, independent device of the fin itself or even board, attached on request when needed. Fins to work with detector must be specially prepared- by imbedding conductor or spraying , painting conducting path along.As to exact method of detecting weed on the fin , we need go back to electronic laboratory, check capacitance, ultrasound, magnetic properties/ inducting. Wires or no wires technology to synchronize fin with control box.

I think that our guy that did our motion gps will good start to implement idea.

Mmmmmmmm No.
1 extra drag from wire2 something extra for weed to wrap around

3 the vibration noise from the wire

4 damage to the fin from the wire slapping at it

5 you can feel weed on your fin if you care to listen

6 to get weed off chop jump or spin the board sideways, takes 5 secs.

1-4 no,no
wire is actually molded inside the fin already, during fabrication process,
under the skin
my picture only illustrate approx location
such fin could be called e-fin ( electronic fin or Macro fin in short)
6. Good tip with this sideways, I need to try soon. Unfortunately jumping on chop doesn't help me here to get the weed of. Maybe we have the nasty , different sticky weed here?

Hasn't anyone realised exposed wires and water don't work.
What about a lever on the boom that pivots the fin back.

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kato said..
Try this for an idea. A shrinking fin...starts out as a 32 and the faster you go the smaller it gets. A retractable one won't work as there is too much drag from the slot. A changing angle might

retractable should be possible but again:
-we need exactly same profile on retractable part
-need some electric motor propulsion- then we need some space on top of the board, when fin could pop up
-we may need as much as 10 cm or even more to get from 32 to 15cm at full speed down wind
I do agree
swinging back fin will be much easier to do- but efficiency of such fin will be limited- due to resistance to water, drag
if we could do telescopic fin the could be ideal, but any imperfection in the joint mean turbulence -and all gain lost,
but temporary swing to get rid of weed could be ideal

Retractable fin will be blessing for our speed boards if done one day. I have always problem to arrive to spot , up wind.With retractable we could easy double the size and get over chop to high point.

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Imax1 said..
Hasn't anyone realised exposed wires and water don't work.
What about a lever on the boom that pivots the fin back.

nope, wires are hidden inside the fibreglass, carbon structure.
the easiest could be cutting small grove with grinder, putting coper wire, glueing back with resin to hide grove, polishing to restore arc shape.
Using metalic , conducting paint also should do the job, but it reliable

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Macroscien said..

Imax1 said..
Hasn't anyone realised exposed wires and water don't work.
What about a lever on the boom that pivots the fin back.

nope, wires are hidden inside the fibreglass, carbon structure.
the easiest could be cutting small grove with grinder, putting coper wire, glueing back with resin to hide grove, polishing to restore arc shape.
Using metalic , conducting paint also should do the job, but it reliable

Eh...so copper wire to conduct the electricity? Groove ground into the fin to fit it, Carbon is a better electrical conductor to start with. So are you fitting some kind of micro proximity sensor or other gizmo on the end of this wire to actually detect the weed?

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peterowensbabs said..

Macroscien said..

Imax1 said..
Hasn't anyone realised exposed wires and water don't work.
What about a lever on the boom that pivots the fin back.

nope, wires are hidden inside the fibreglass, carbon structure.
the easiest could be cutting small grove with grinder, putting coper wire, glueing back with resin to hide grove, polishing to restore arc shape.
Using metalic , conducting paint also should do the job, but it reliable

Eh...so copper wire to conduct the electricity? Groove ground into the fin to fit it, Carbon is a better electrical conductor to start with. So are you fitting some kind of micro proximity sensor or other gizmo on the end of this wire to actually detect the weed?

Coper wire ( or any other conductor) is used as sensor , antena rather then electric switch. Remember that our wire is covered with insulating plastic. But our smart Electronic circuit , gizmo is able to detect if any sort of material , other then water density is in close proximity to our fin. that brings me idea of another very useful invention that we could incorporate in our next board ! ultrasonic depth sounder!

I'm surprised no one has suggested attaching one end of the wire to the sailor's arsehole, this way you won't need an audible signal

What you need to develop Macro is the 3 bladed rotating fin. Only "one" blade exposed below the board at a time. (You'd need a little hump on the deck to house the 2 dry blades, maybe a twin fin arrangement and 6 shorter blades. to keep dimensions down ) You could control the speed of rotation using a little brake lever on the boom. i.e.. at 50 knots you could keep rotation such that the fins were only doing 35 knots water speed - solves both the cavitation and weed problem. (Plus if you flaunt the WSSRC depth ruling, touch bottom, release the brake, you'll really get up and boogie - nobody will notice)

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kato said..
Try this for an idea. A shrinking fin...starts out as a 32 and the faster you go the smaller it gets. A retractable one won't work as there is too much drag from the slot. A changing angle might

That could be done

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John340 said..
I'm surprised no one has suggested attaching one end of the wire to the sailor's arsehole, this way you won't need an audible signal

Nut sack would work

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Ian K said..
What you need to develop Macro is the 3 bladed rotating fin. Only "one" blade exposed below the board at a time. (You'd need a little hump on the deck to house the 2 dry blades, maybe a twin fin arrangement and 6 shorter blades. to keep dimensions down ) You could control the speed of rotation using a little brake lever on the boom. i.e.. at 50 knots you could keep rotation such that the fins were only doing 35 knots water speed - solves both the cavitation and weed problem. (Plus if you flaunt the WSSRC depth ruling, touch bottom, release the brake, you'll really get up and boogie - nobody will notice)

That might be a bit like having a slipping clutch instead of a derailleur to change gearing on your pushy. Methinks you may end up with heat generation instead of torque multiplication. You may perhaps use the output from the rotating fin to drive a propeller instead.

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kato said..
Try this for an idea. A shrinking fin...starts out as a 32 and the faster you go the smaller it gets. A retractable one won't work as there is too much drag from the slot. A changing angle might

Perhaps the deployment and retraction of the swingwing could be controlled using slip angle sensing from Juliens Motion so that the fin always had the correct level of deployment to operate at the most efficient angle of attack.

a bit off topic but peter nitschke and myself were mucking around with retracting fin ideas in the late 90's. started thinking about it with raceboards. i'm pretty sure peter had seen someone doing it in Europe.

we were trying to lower the planing threshold of old style long narrow slalom boards so started carrying big fins and big sails. the problem was the big fins and narrower boards had a small window of control then started to porpoise.

the idea was the fin sat between 2 neoprene pressure plates and extend above the deck so you could pull the fin up and down to suit. we were about to implement it into a prototype board but wide style boards happened and resolved all of the issues we were having with longer narrow boards of the time.

i started sailing 90cm formula boards

you could do something similar with a speed board. or even do a pivoting fin. have it on a spring setup for the load at speed. as you go faster and the drag increases the fin tip can pivot back resulting in a shorter fin.

Select to expand quote

Gestalt said..
a bit off topic but peter nitschke and myself were mucking around with retracting fin ideas in the late 90's. started thinking about it with raceboards. i'm pretty sure peter had seen someone doing it in Europe.

we were trying to lower the planing threshold of old style long narrow slalom boards so started carrying big fins and big sails. the problem was the big fins and narrower boards had a small window of control then started to porpoise.

the idea was the fin sat between 2 neoprene pressure plates and extend above the deck so you could pull the fin up and down to suit. we were about to implement it into a prototype board but wide style boards happened and resolved all of the issues we were having with longer narrow boards of the time.

i started sailing 90cm formula boards

you could do something similar with a speed board. or even do a pivoting fin. have it on a spring setup for the load at speed. as you go faster and the drag increases the fin tip can pivot back resulting in a shorter fin.

It may be that if the smaller fin begins to loose grip the drag increases and further decreases fin size thus snowballing the problem.

Select to expand quote

Gestalt said..
a bit off topic but peter nitschke and myself were mucking around with retracting fin ideas in the late 90's. started thinking about it with raceboards. i'm pretty sure peter had seen someone doing it in Europe.

we were trying to lower the planing threshold of old style long narrow slalom boards so started carrying big fins and big sails. the problem was the big fins and narrower boards had a small window of control then started to porpoise.

the idea was the fin sat between 2 neoprene pressure plates and extend above the deck so you could pull the fin up and down to suit. we were about to implement it into a prototype board but wide style boards happened and resolved all of the issues we were having with longer narrow boards of the time.

i started sailing 90cm formula boards

you could do something similar with a speed board. or even do a pivoting fin. have it on a spring setup for the load at speed. as you go faster and the drag increases the fin tip can pivot back resulting in a shorter fin.

I saw an article in some magazine way back in the '80's where someone had built and experimented with a retractable fin. It had photos and diagrams. They had mechanical actuation and sealing issues if I recall correctly.

Select to expand quote

REDhat said..

Gestalt said..
a bit off topic but peter nitschke and myself were mucking around with retracting fin ideas in the late 90's. started thinking about it with raceboards. i'm pretty sure peter had seen someone doing it in Europe.

we were trying to lower the planing threshold of old style long narrow slalom boards so started carrying big fins and big sails. the problem was the big fins and narrower boards had a small window of control then started to porpoise.

the idea was the fin sat between 2 neoprene pressure plates and extend above the deck so you could pull the fin up and down to suit. we were about to implement it into a prototype board but wide style boards happened and resolved all of the issues we were having with longer narrow boards of the time.

i started sailing 90cm formula boards

you could do something similar with a speed board. or even do a pivoting fin. have it on a spring setup for the load at speed. as you go faster and the drag increases the fin tip can pivot back resulting in a shorter fin.

It may be that if the smaller fin begins to loose grip the drag increases and further decreases fin size thus snowballing the problem.

yeah it's adding an extra dimension of calculations for sure.

Select to expand quote

sailquik said..

Gestalt said..
a bit off topic but peter nitschke and myself were mucking around with retracting fin ideas in the late 90's. started thinking about it with raceboards. i'm pretty sure peter had seen someone doing it in Europe.

we were trying to lower the planing threshold of old style long narrow slalom boards so started carrying big fins and big sails. the problem was the big fins and narrower boards had a small window of control then started to porpoise.

the idea was the fin sat between 2 neoprene pressure plates and extend above the deck so you could pull the fin up and down to suit. we were about to implement it into a prototype board but wide style boards happened and resolved all of the issues we were having with longer narrow boards of the time.

i started sailing 90cm formula boards

you could do something similar with a speed board. or even do a pivoting fin. have it on a spring setup for the load at speed. as you go faster and the drag increases the fin tip can pivot back resulting in a shorter fin.

I saw an article in some magazine way back in the '80's where someone had built and experimented with a retractable fin. It had photos and diagrams. They had mechanical actuation and sealing issues if I recall correctly.

might be the same thing. i'll ask him next time i see him.

from memory i think peter thought the idea he had seen was too complicated and friction plates were a simpler answer.

Maybe use a weed fin!