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eastcoast said..
Subsonic was it as negative as this?

Er no. Well not yet anyway. He's quite good at destroying boards.

We should hook up

The SB W44 is at a board builder having the negative rocker repaired. He's going to use epoxy to fill, then sand it out......

i get it back in a week or so, I'm going to refurbish the deck as it is looking very rough and worn out.

The plan is to remove the foot pads. Fully sand to smooth finish (orbital sander and some by hand). Spray with 1k primer (blue). Then spray with acrylic paint (blue). Attach new vinyl graphics. Spray with 1k clear coat and sprinkle non slip granules on whilst surface is still wet. Then a final 1k clear coat. Cut and fit new foot pads.

Does this plan sound right? Worth mentioning the W44 is the wood version.

Select to expand quote

mark62 said..
The SB W44 is at a board builder having the negative rocker repaired. He's going to use epoxy to fill, then sand it out......

i get it back in a week or so, I'm going to refurbish the deck as it is looking very rough and worn out.

The plan is to remove the foot pads. Fully sand to smooth finish (orbital sander and some by hand). Spray with 1k primer (blue). Then spray with acrylic paint (blue). Attach new vinyl graphics. Spray with 1k clear coat and sprinkle non slip granules on whilst surface is still wet. Then a final 1k clear coat. Cut and fit new foot pads.

Does this plan sound right? Worth mentioning the W44 is the wood version.

Please report back how the board goes with the negative rocker removed mark - interested to hear if you found it changed anything

At 3 minutes, AB mentions negative tail rocker

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mark62 said..
At 3 minutes, AB mentions negative tail rocker

I've forgotten about this vid. I have 2 AB+ boards and the 90litre 59wide is a dream board. The 78 litr 54wide(?) is a vixen but when she comes out of repair shop I hope she too will be a dream to ride. Very fast boards too.
All AB+ boards that I have seen have been repaired between the straps. Top deck cracking. I'll put a straight edge on them to see if neg rocker is present. And my older boards too.

It'll be interesting to see if the AB boards suffer with it too. I'm starting to realise that most boards will develop negative rocker at some point. I guess regardless of construction tricks/designs, the styrene core can only take so much pounding and will stay compressed at some point.

I picked up my SB W44 from the board builders today, he's done a great job. Epoxied, sand back it back to its original shape and sprayed with epoxy resin paint. I've sand it with 600, the 800 wet n dry, tomorrow I'll use 1200 to finish it off. I asked him to add a tiny bit of positive rocker. I think the positive rocker will settle down and become neutral after two or three heavy down wind sessions.

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BSN101 said..

mark62 said..
At 3 minutes, AB mentions negative tail rocker

I've forgotten about this vid. I have 2 AB+ boards and the 90litre 59wide is a dream board. The 78 litr 54wide(?) is a vixen but when she comes out of repair shop I hope she too will be a dream to ride. Very fast boards too.
All AB+ boards that I have seen have been repaired between the straps. Top deck cracking. I'll put a straight edge on them to see if neg rocker is present. And my older boards too.

My AB+ 54 is fine still going strong great speed board

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choco said..

BSN101 said..

mark62 said..
At 3 minutes, AB mentions negative tail rocker

I've forgotten about this vid. I have 2 AB+ boards and the 90litre 59wide is a dream board. The 78 litr 54wide(?) is a vixen but when she comes out of repair shop I hope she too will be a dream to ride. Very fast boards too.
All AB+ boards that I have seen have been repaired between the straps. Top deck cracking. I'll put a straight edge on them to see if neg rocker is present. And my older boards too.

My AB+ 54 is fine still going strong great speed board

I'm 3rd hand that I know of. I missed it on Gumtree then got it of local demon in poor state. Getting sorted now. Finish very soon.
It had a habit of trying to make you dismount unexpectedly. Any hints or tuning tips? Sail size & fin combinations?
Cheers Dave

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BSN101 said..

choco said..

BSN101 said..

mark62 said..
At 3 minutes, AB mentions negative tail rocker

I've forgotten about this vid. I have 2 AB+ boards and the 90litre 59wide is a dream board. The 78 litr 54wide(?) is a vixen but when she comes out of repair shop I hope she too will be a dream to ride. Very fast boards too.
All AB+ boards that I have seen have been repaired between the straps. Top deck cracking. I'll put a straight edge on them to see if neg rocker is present. And my older boards too.

My AB+ 54 is fine still going strong great speed board

I'm 3rd hand that I know of. I missed it on Gumtree then got it of local demon in poor state. Getting sorted now. Finish very soon.
It had a habit of trying to make you dismount unexpectedly. Any hints or tuning tips? Sail size & fin combinations?
Cheers Dave

Gave my board a new paint job over summer to freshen it up, in flat water you can run very small fins in the board track 3cm from fully back, I've found in choppy water with 30-32cm fin it has a strange tendency to kick out side ways every now and then probably my ropes and setup.(My best times on it below), lent the board to Spotty and he got a 45knt peak out of it and 40+knot NM from memory but he could do that on a one design

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Gave my board a new paint job over summer to freshen it up, in flat water you can run very small fins in the board track 3cm from fully back, I've found in choppy water with 30-32cm fin it has a strange tendency to kick out side ways every now and then probably my ropes and setup.(My best times on it below), lent the board to Spotty and he got a 45knt peak out of it and 40+knot NM from memory but he could do that on a one design

Nice colour Choc

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firiebob said..

Gave my board a new paint job over summer to freshen it up, in flat water you can run very small fins in the board track 3cm from fully back, I've found in choppy water with 30-32cm fin it has a strange tendency to kick out side ways every now and then probably my ropes and setup.(My best times on it below), lent the board to Spotty and he got a 45knt peak out of it and 40+knot NM from memory but he could do that on a one design

Nice colour Choc

You always said red was faster Firie

43.5 (45 Spotty) not bad for a 54cm board. Ever figure out why it handles the way it does?

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yoyo said..
43.5 (45 Spotty) not bad for a 54cm board. Ever figure out why it handles the way it does?

Only use the board at Lake George nowdays too gusty at my home spot so never bothered trying to figure it out, nice on the flat water though just keeps on accelerating fun to sail.

An interesting topic! Makes me wonder. I own a set of the superb '14 Mistral's designed by Chris Lockwood. I have different feelings among them: while the 91 and 137 are sooo smooth gliding and seem to have endless windrange, the 112 feels a bit "harsh" on a full 7.0 (CL SL2 34 or 37). Gets some better when I can use lifty fins such as the Tectonics Matrix 37, but I can do that only in smoother waters (as the Matrix doesn't have as much lift as the SL2 at slow speed, meaning it works only if not slowed down by incoming chop).
I checked the bottom of my boards and, while 91 and 137 are perfectly flat, the 112 shows some very slight "light", I think it's less than 1/2 mm, but there it is. As I am totally in love with the boards, in 2018 I started searching for a new pristine 112, but it's not such an easy board to find in Italy. I had occasion to check the one of a friend and it showed about the same "light" as mine. In the end I decided to buy an used one from NL, after explaining the seller what I was looking for, being assured the board was OK, having a common friend involved so to grant the seller was true, being assured the board was used by a very light sailor on smooth NL channels waters only ... I got the board, checked it and found it's just more or less the same as mine. So I am starting to think that maybe the mould itself is not perfect, as it seems it is for some SB and PD boards mentioned above. And maybe it's actually just me having problems on my 112s through step chop with a full 7.0.
Who knows.
Any hints or thoughts?
I mean, while waiting for the next products from CL's pencil...

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geoITA
So I am starting to think that maybe the mould itself is not perfect...
Any hints or thoughts?

Think you are right on this.

Select to expand quote

geoITA said..
An interesting topic! Makes me wonder. I own a set of the superb '14 Mistral's designed by Chris Lockwood. I have different feelings among them: while the 91 and 137 are sooo smooth gliding and seem to have endless windrange, the 112 feels a bit "harsh" on a full 7.0 (CL SL2 34 or 37). Gets some better when I can use lifty fins such as the Tectonics Matrix 37, but I can do that only in smoother waters (as the Matrix doesn't have as much lift as the SL2 at slow speed, meaning it works only if not slowed down by incoming chop).
I checked the bottom of my boards and, while 91 and 137 are perfectly flat, the 112 shows some very slight "light", I think it's less than 1/2 mm, but there it is. As I am totally in love with the boards, in 2018 I started searching for a new pristine 112, but it's not such an easy board to find in Italy. I had occasion to check the one of a friend and it showed about the same "light" as mine. In the end I decided to buy an used one from NL, after explaining the seller what I was looking for, being assured the board was OK, having a common friend involved so to grant the seller was true, being assured the board was used by a very light sailor on smooth NL channels waters only ... I got the board, checked it and found it's just more or less the same as mine. So I am starting to think that maybe the mould itself is not perfect, as it seems it is for some SB and PD boards mentioned above. And maybe it's actually just me having problems on my 112s through step chop with a full 7.0.
Who knows.
Any hints or thoughts?
I mean, while waiting for the next products from CL's pencil...

It's really hard to measure the gap. When I looked at mine, the light under the straight edge made the gap look huge. I used standard 80g A4 paper the measure the gap. On my SB W49, the gap was the equivalent of four A4 sheets. I repaired it by building up three or for coats of 2 pack epoxy paint in the effected area, then faired it in with a good sanding block. It's perfect now.

The gap was much bigger on my other board (W44), so I gave this one to a local board builder to repair as it need filling and fairing in properly.

Select to expand quote

mark62 said..

geoITA said..
An interesting topic! Makes me wonder. I own a set of the superb '14 Mistral's designed by Chris Lockwood. I have different feelings among them: while the 91 and 137 are sooo smooth gliding and seem to have endless windrange, the 112 feels a bit "harsh" on a full 7.0 (CL SL2 34 or 37). Gets some better when I can use lifty fins such as the Tectonics Matrix 37, but I can do that only in smoother waters (as the Matrix doesn't have as much lift as the SL2 at slow speed, meaning it works only if not slowed down by incoming chop).
I checked the bottom of my boards and, while 91 and 137 are perfectly flat, the 112 shows some very slight "light", I think it's less than 1/2 mm, but there it is. As I am totally in love with the boards, in 2018 I started searching for a new pristine 112, but it's not such an easy board to find in Italy. I had occasion to check the one of a friend and it showed about the same "light" as mine. In the end I decided to buy an used one from NL, after explaining the seller what I was looking for, being assured the board was OK, having a common friend involved so to grant the seller was true, being assured the board was used by a very light sailor on smooth NL channels waters only ... I got the board, checked it and found it's just more or less the same as mine. So I am starting to think that maybe the mould itself is not perfect, as it seems it is for some SB and PD boards mentioned above. And maybe it's actually just me having problems on my 112s through step chop with a full 7.0.
Who knows.
Any hints or thoughts?
I mean, while waiting for the next products from CL's pencil...

It's really hard to measure the gap. When I looked at mine, the light under the straight edge made the gap look huge. I used standard 80g A4 paper the measure the gap. On my SB W49, the gap was the equivalent of four A4 sheets. I repaired it by building up three or for coats of 2 pack epoxy paint in the effected area, then faired it in with a good sanding block. It's perfect now.

The gap was much bigger on my other board (W44), so I gave this one to a local board builder to repair as it need filling and fairing in properly.

Thank you! This confirms my experience. Not easy to assess it clearly, but backlight makes it seem probably worse than real. Good idea to check with paper sheets! Will do the same as soon as possible.

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brett_perth said..

mark62 said..
The SB W44 is at a board builder having the negative rocker repaired. He's going to use epoxy to fill, then sand it out......

i get it back in a week or so, I'm going to refurbish the deck as it is looking very rough and worn out.

The plan is to remove the foot pads. Fully sand to smooth finish (orbital sander and some by hand). Spray with 1k primer (blue). Then spray with acrylic paint (blue). Attach new vinyl graphics. Spray with 1k clear coat and sprinkle non slip granules on whilst surface is still wet. Then a final 1k clear coat. Cut and fit new foot pads.

Does this plan sound right? Worth mentioning the W44 is the wood version.

Please report back how the board goes with the negative rocker removed mark - interested to hear if you found it changed anything

Finally got to try out the W44 with the tail mod. My original PB was 5 x 10 secs @ 41.3k done in 2012 (on this same board). Whilst I've got close t9 my PB several times, I've not been able to improve on it, frustrating at times.

today in less than perfect conditions, I finally got a new 5 x 10 sec PB, 42.4k. Pretty much every run was peaks of 42/43 knots, and 44k best on the day.

with the tail mod, the board felt way less sticky.

I'm pretty sure the board is faster than before.

Select to expand quote

mark62 said..

brett_perth said..

mark62 said..
The SB W44 is at a board builder having the negative rocker repaired. He's going to use epoxy to fill, then sand it out......

i get it back in a week or so, I'm going to refurbish the deck as it is looking very rough and worn out.

The plan is to remove the foot pads. Fully sand to smooth finish (orbital sander and some by hand). Spray with 1k primer (blue). Then spray with acrylic paint (blue). Attach new vinyl graphics. Spray with 1k clear coat and sprinkle non slip granules on whilst surface is still wet. Then a final 1k clear coat. Cut and fit new foot pads.

Does this plan sound right? Worth mentioning the W44 is the wood version.

Please report back how the board goes with the negative rocker removed mark - interested to hear if you found it changed anything

Finally got to try out the W44 with the tail mod. My original PB was 5 x 10 secs @ 41.3k done in 2012 (on this same board). Whilst I've got close t9 my PB several times, I've not been able to improve on it, frustrating at times.

today in less than perfect conditions, I finally got a new 5 x 10 sec PB, 42.4k. Pretty much every run was peaks of 42/43 knots, and 44k best on the day.

with the tail mod, the board felt way less sticky.

I'm pretty sure the board is faster than before.

With so much going on while blasting across the water it's amazing that it does make a difference

Select to expand quote

choco said..

mark62 said..

brett_perth said..

mark62 said..
The SB W44 is at a board builder having the negative rocker repaired. He's going to use epoxy to fill, then sand it out......

i get it back in a week or so, I'm going to refurbish the deck as it is looking very rough and worn out.

The plan is to remove the foot pads. Fully sand to smooth finish (orbital sander and some by hand). Spray with 1k primer (blue). Then spray with acrylic paint (blue). Attach new vinyl graphics. Spray with 1k clear coat and sprinkle non slip granules on whilst surface is still wet. Then a final 1k clear coat. Cut and fit new foot pads.

Does this plan sound right? Worth mentioning the W44 is the wood version.

Please report back how the board goes with the negative rocker removed mark - interested to hear if you found it changed anything

Finally got to try out the W44 with the tail mod. My original PB was 5 x 10 secs @ 41.3k done in 2012 (on this same board). Whilst I've got close t9 my PB several times, I've not been able to improve on it, frustrating at times.

today in less than perfect conditions, I finally got a new 5 x 10 sec PB, 42.4k. Pretty much every run was peaks of 42/43 knots, and 44k best on the day.

with the tail mod, the board felt way less sticky.

I'm pretty sure the board is faster than before.

With so much going on while blasting across the water it's amazing that it does make a difference

Before last Monday's session, I would have fully agreed. I figured that for an average speed sailor like me, surely half a millimetre negative tail rocker wouldn't really effect my speeds.

But, I noticed the difference immediately, less sticky and attached to the water (in a good way), It just glided nicely, my stance felt much more natural and I was using less energy. The board seemed to accelerate better in gusts too.

i don't get to use the W44 much as it needs a lot of wind. I used it two or three times this year (pre tail repair) in better stronger winds and only getting 39+k 5 x 10 secs and 41k peaks.

Hopefully if we get flatter water and stronger winds at WK this winter, I can see if I can improve on the speeds again.
I'd defo recommend repairing negative tail rocker:)

In the end I took a decision ...
My SL112 right now is in the expert hands of Aurelio Verdi, getting a careful bottom fairing. He told me he found plenty of work to do.
Can't wait to have it finished and to sail it again!

I've filled and sanded the negative tail rocker on my SB Speed W58, the gap was pretty big. It just needs painting and it's good to go.

For anyone thinking about doing the repair themselves, it's easier if you mark off the various sections first. On mine, I marked the centre line, and where the double concave becomes flat vee, then where the tail kick starts etc. I then worked each section individually. Good light and a 2m straight edge are essential too.

I think you'll notice quite a difference when you take it for a blast.
Yes, side lights are a great help, but only use one at a time.

The negative rocker occurs by having a too thin sandwich and hitting chop. The sandwich thickness is very important for resistance against bending. It goes up by the 3rd exponent of the thickness so already from 4 to 5mm is nearly double the stiffness (4?=64, 5?=125) but costs hardly any weight. Also usually there is only 80gr glass between EPS and PVC and both the inside and outside laminate are important for the stiffness. We use 6mm PVC which gets tapered towards the nose and thin triax carbon on the inside.

When repairing boards that have gone negative, concave or soft, we use the created space to make it stiffer again. Either add PVC if there is a lot of space to be filled. Or If it is just a few mm we use various layers of thick carbon in steps from big to small to fill this. Without removing the PVC and reinforcing the inner laminate (which would be sh!tloads of work), this gives the most increase in stiffness so that the repair will last at least as long as the expected remaining life span of the board. Most fillers that are easy to sand are quite soft and will hardly make it stiffer. Off course the inside laminate will have to be repaired if it has broken but that will not be the case if a board "just" has a negative rocker.

Select to expand quote

Witchcraft said..
The negative rocker occurs by having a too thin sandwich and hitting chop. The sandwich thickness is very important for resistance against bending. It goes up by the 3rd exponent of the thickness so from 4 to 5mm is nearly double the stiffness but costs hardly any weight. Also usually there is only 80gr glass between EPS and PVC and both the inside and outside laminate are important for the stiffness. We use 6mm PVC and thin triax carbon on the inside.

When repairing boards that have gone negative, concave or soft, we use the created space to make it stiffer again. Either add PVC if there is a lot of space to be filled. Or If it is just a few mm we use various layers of thick carbon in steps from big to small to fill this. Without removing the PVC and reinforcing the inner laminate (which would be sh!tloads of work), this gives the most increase in stiffness so that the repair will last at least as long as the expected remaining life span of the board. Most fillers that are easy to sand are quite soft and will hardly make it stiffer. Off course the inside laminate will have to be repaired if it has broken but that will not be the case if a board "just" has a negative rocker.

Interesting, cheers

Decided to have a go at sorting out the negative tail rocker on my SB iS130 (85cm wide). I was a bit worried about attempting this one because it's mono concave and much bigger than the other boards I've fixed so far. Turns out there was nothing to worry about, pretty straightforward. I just need to try it out and check it feels right, then I'll repaint the bottom. I filled the hollow with epoxy, (no micro balloons), hoping it'll add a little stiffness. The epoxy is pretty hard and took nearly 5 hours to sand by hand. But at least there is no negative tail rocker