Fin Size

agrelon · 14th May 2009, 10:16 PM

I have a question about fin size.

I sail a 125l, 75cm wide board with a 49cm fin. Only once I really get speed, the board sort of takes off and I believe the fin maybe to big for planing conditions.

Also, I'm very lightweight. 54kg with harness. Would a smaller fin give me more control at higher speeds?

Thanks.

agrelon · 14th May 2009, 10:17 PM

An when i say take off i dont just mean planing i mean lift off.

PG · 15th May 2009, 01:16 AM

Yes, the fin is probably too big (but it depends somewhat on the board type as well).

I guess that with your weight you typically use sails no bigger than 6.5 m2. If so, then a 40 cm fin ought to be plenty. Depending on what board it is you may even be able to shave off a few cm off that.

Based on almost "no background info" I would say get a 40 cm second fin and things will look a lot better.

agrelon · 15th May 2009, 10:08 PM

Quote:

Originally Posted by PG

Yes, the fin is probably too big (but it depends somewhat on the board type as well).

I guess that with your weight you typically use sails no bigger than 6.5 m2. If so, then a 40 cm fin ought to be plenty. Depending on what board it is you may even be able to shave off a few cm off that.

Based on almost "no background info" I would say get a 40 cm second fin and things will look a lot better.

Sorry for the lack of precision. The board is an AHD 2005 limited edition planing oriented board. http://www.a-h-d.com/boards/windsurf...mited-edition/

74 cm wide, very flat.

You're right about the sail, my biggest sail is 6.0m at the moment. I think that because the board is so flat and wide, it has a tendency to lift off and therefore that is why it has such a large fin at the moment. (not my board, a friend's I'm borrowing)

Ken · 15th May 2009, 10:44 PM

Given your size, your board would be great for light winds with 7.5 -8.5 sail in under 15 knots.

It's way too big for anything over 15 knots. Yes a smaller fin would help (40cm), but the board is the problem. As I recall, the AHD's have very hard rails, flat bottoms, pretty light and fragile. They are somewhat challenging to jibe.

If you are using a 6.0 in say: 14 - 20 knots, you should be on a board around 90 liters or smaller.

agrelon · 16th May 2009, 10:11 AM

Quote:

Originally Posted by Ken

Given your size, your board would be great for light winds with 7.5 -8.5 sail in under 15 knots.

It's way too big for anything over 15 knots. Yes a smaller fin would help (40cm), but the board is the problem. As I recall, the AHD's have very hard rails, flat bottoms, pretty light and fragile. They are somewhat challenging to jibe.

If you are using a 6.0 in say: 14 - 20 knots, you should be on a board around 90 liters or smaller.

Yeah, once I start really going fast the board becomes uncontrollable, (and for some reason really hard to get into the foot straps without the whole board carving upwind

) At the moment I'm just wondering whether my skills are good enough for a smaller board.. I can beach start, water start, quick tack, use harness / footstraps and occasionally jibe, but I've never tried a board smaller than 115l...

I'm looking at this second hand board which is 120l but much thinner, something like in the 50cms, and f***ing light weight. I think that this would handle speed much better due to the smaller width, and therefore less lift, easier to steer etc. What do you think?

Thanks.

COACHG · 17th May 2009, 06:39 AM

The LTD you are sailing is a remake of the earlier AHD Freediamonds. They had a big single concave up front washing into a fair amount of vee in the back. Very soft, tucked rails. Those boards were smooth, soft riding and easy to jibe. I have the 2000 Freediamond 65, which is the 115 liter version. At my weight, around 75 kilos, a 6.0 is about the smallest size sail the 115 liter board will take. Maybe squeeze a 5.5 on a flat water day and no bigger then a 42 cm fin. So at your weight with the same board that is 10 liters bigger with a 6.0? Way to big fin and too much wind.

By the way, I can easily uphaul my 115, so you should be able to go smaller at your weight.

Coachg

agrelon · 18th May 2009, 04:27 PM

Quote:

Originally Posted by COACHG

The LTD you are sailing is a remake of the earlier AHD Freediamonds. They had a big single concave up front washing into a fair amount of vee in the back. Very soft, tucked rails. Those boards were smooth, soft riding and easy to jibe. I have the 2000 Freediamond 65, which is the 115 liter version. At my weight, around 75 kilos, a 6.0 is about the smallest size sail the 115 liter board will take. Maybe squeeze a 5.5 on a flat water day and no bigger then a 42 cm fin. So at your weight with the same board that is 10 liters bigger with a 6.0? Way to big fin and too much wind.

By the way, I can easily uphaul my 115, so you should be able to go smaller at your weight.

Coachg

Yeah, I'm looking into a smaller board. Still 120l, but much thinner, (59cm I believe) again it's not perfect but it'll handle speed better i reckon due to the thinner profile. It's a really old board and if I buy it the guy is selling for 60 USD... so yeah it's old, but it is f***ing light weight and thin and slightly less volume so it'll be fast and definitely good training before I get a proper board.

Oh yeah and it doesnt have a fin yet but i reckon I'm gonna put something small on it to make it really fast and because it isn't wide at all. probably around < 40cm

Ken · 20th May 2009, 12:07 AM

I weigh 79 kg and for me, 100 liters is the line between a sinker and floater board. At 54 kg, uphauling a 100 - 120 liter board should be easy. More challenging between 85 and 100 liters, but doable if the water isn't too rough.

No reason not to get a smaller board (85-100 liters) if you can water start. This is where a 6 meter sail will do you the most good.

A 120 liter board for you is still a light wind (10-15 knots) board with a 7.5 or 8.5 sail.

agrelon · 22nd May 2009, 09:20 PM

Quote:

Originally Posted by Ken

I weigh 79 kg and for me, 100 liters is the line between a sinker and floater board. At 54 kg, uphauling a 100 - 120 liter board should be easy. More challenging between 85 and 100 liters, but doable if the water isn't too rough.

No reason not to get a smaller board (85-100 liters) if you can water start. This is where a 6 meter sail will do you the most good.

A 120 liter board for you is still a light wind (10-15 knots) board with a 7.5 or 8.5 sail.

Ok, thanks, I'm still gonna try the 120, cause it's really thin and i've never tried a board thinner than 60cm, and if that goes well i'll definately try to find a smaller board. thanks for the advice!

14th May 2009, 10:16 PM	#1
agrelon Member Join Date: Apr 2009 Posts: 421	Fin Size I have a question about fin size. I sail a 125l, 75cm wide board with a 49cm fin. Only once I really get speed, the board sort of takes off and I believe the fin maybe to big for planing conditions. Also, I'm very lightweight. 54kg with harness. Would a smaller fin give me more control at higher speeds? Thanks.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

14th May 2009, 10:17 PM	#2
agrelon Member Join Date: Apr 2009 Posts: 421	An when i say take off i dont just mean planing i mean lift off.

15th May 2009, 01:16 AM	#3
PG Member Join Date: Aug 2006 Posts: 234	Yes, the fin is probably too big (but it depends somewhat on the board type as well). I guess that with your weight you typically use sails no bigger than 6.5 m2. If so, then a 40 cm fin ought to be plenty. Depending on what board it is you may even be able to shave off a few cm off that. Based on almost "no background info" I would say get a 40 cm second fin and things will look a lot better.

15th May 2009, 10:44 PM	#5
Ken Member Join Date: Aug 2006 Location: Dallas, Texas USA Posts: 799	Given your size, your board would be great for light winds with 7.5 -8.5 sail in under 15 knots. It's way too big for anything over 15 knots. Yes a smaller fin would help (40cm), but the board is the problem. As I recall, the AHD's have very hard rails, flat bottoms, pretty light and fragile. They are somewhat challenging to jibe. If you are using a 6.0 in say: 14 - 20 knots, you should be on a board around 90 liters or smaller.

17th May 2009, 06:39 AM	#7
COACHG Member Join Date: Jan 2009 Location: Northern California Posts: 147	The LTD you are sailing is a remake of the earlier AHD Freediamonds. They had a big single concave up front washing into a fair amount of vee in the back. Very soft, tucked rails. Those boards were smooth, soft riding and easy to jibe. I have the 2000 Freediamond 65, which is the 115 liter version. At my weight, around 75 kilos, a 6.0 is about the smallest size sail the 115 liter board will take. Maybe squeeze a 5.5 on a flat water day and no bigger then a 42 cm fin. So at your weight with the same board that is 10 liters bigger with a 6.0? Way to big fin and too much wind. By the way, I can easily uphaul my 115, so you should be able to go smaller at your weight. Coachg

20th May 2009, 12:07 AM	#9
Ken Member Join Date: Aug 2006 Location: Dallas, Texas USA Posts: 799	I weigh 79 kg and for me, 100 liters is the line between a sinker and floater board. At 54 kg, uphauling a 100 - 120 liter board should be easy. More challenging between 85 and 100 liters, but doable if the water isn't too rough. No reason not to get a smaller board (85-100 liters) if you can water start. This is where a 6 meter sail will do you the most good. A 120 liter board for you is still a light wind (10-15 knots) board with a 7.5 or 8.5 sail.