Hello everyone, geat forum btw. I own a simmer scr 2019. Very nice sail with excellent built quality. I bought it with a rrd dynamic sdm pro 100% carbon content 2018 mast. The local dealer from who i bought the sail said that it's a perfect mast for the sail. I made my own investigation and i discovered that rrd and simmer are all progressive constant curves. From the unifiber mast selector rrd sdm masts and simmer sdm masts are perfectly matched. But the cams are not rotating well. Especially on the starboard tack even if the wind is strong. What should i do? Buy the original simmer mast? Maybe add more downhaul and less outhaul?
Because it was much more expensive (it was brand new) and the rrd mast was slightly used and the local dealer said that rrd and simmer are super compatible and i will not have a problem
They maybe both progressive constant curve but the RRD is probably a wider diameter thus not compatible. 
Go back to your local dealer and swap over.
Or check diameter of the Simmer mast vs the RRD. If he said it was compatible but they are different then he should be imbarressed and help you out.
Select to expand quoteAUS4 said..
They maybe both progressive constant curve but the RRD is probably a wider diameter thus not compatible.
Wider? Now that's something i didn't knew.(im windsurfing for about 2.5 years :P) When both masts are rdm or sdm doesn't this mean that their diameter is the same? I mean both my rrd and the simmer mast are sdm masts
Hi Alex ,not all SDM's are the same width ..
I Have just recently brought 2 simmer sails ,but i brought RDM cams ,as i knew that the SIMMER RDM 's and ezzy RDM'S where the same width
seem I have EZZY mast .
have you tried backing your cam batten tension off a bit ....then maybe try more down haul ...
its hard to beat the same brand combo .
Hi Alex
Where are you based? If you are in Perth, then I can lent you a Simmer SDM mast, so you can compare.
The rotation should be very smooth on those SCR sails, with the right mast.
All simmer masts are constant curve. All Simmer sails are for constant curve mast. Been for years and will be for years.
Don't trust the Uni fibre mast chart 100%.
Like mentioned there can be different diameter of the mast section, coming into play.
Select to expand quoteTardy said..
Hi Alex ,not all SDM's are the same width ..
I Have just recently brought 2 simmer sails ,but i brought RDM cams ,as i knew that the SIMMER RDM 's and ezzy RDM'S where the same width
seem I have EZZY mast .
have you tried backing your cam batten tension off a bit ....then maybe try more down haul ...
its hard to beat the same brand combo .
And your are not having problem with rotation right? ok i will try backing the cam batten tension a bit and add more downhaul. Thanks!
Select to expand quotesboardcrazy said..
Have you removed any spacers? That may help.
Unfortunately there are no spacers in the cams
Select to expand quoteSail Repair WA said..
Hi Alex
Where are you based? If you are in Perth, then I can lent you a Simmer SDM mast, so you can compare.
The rotation should be very smooth on those SCR sails, with the right mast.
All simmer masts are constant curve. All Simmer sails are for constant curve mast. Been for years and will be for years.
Don't trust the Uni fibre mast chart 100%.
Like mentioned there can be different diameter of the mast section, coming into play.
Thanks a lot for the information! Unfortunately i'm not living in Perth.
Hi Alex
If you got any pictures when you have them rigged up, then it would be handy.
Just to see if the shape etc, looks the same as on the Simmer masts.
Yes the SCR comes without any spacers on the cam tongues (so you can only add spacers if needed).
On the Simmer mast all my SCR rigs straight out of the bag, with no spacers needed on the recommended settings.
J
Select to expand quoteSail Repair WA said..
Hi Alex
If you got any pictures when you have them rigged up, then it would be handy.
Just to see if the shape etc, looks the same as on the Simmer masts.
Yes the SCR comes without any spacers on the cam tongues (so you can only add spacers if needed).
On the Simmer mast all my SCR rigs straight out of the bag, with no spacers needed on the recommended settings.
J
Of course, i will post pictures today..thanks a lot again :)
Select to expand quoteAlexRms said..Sail Repair WA said..
Hi Alex
If you got any pictures when you have them rigged up, then it would be handy.
Just to see if the shape etc, looks the same as on the Simmer masts.
Yes the SCR comes without any spacers on the cam tongues (so you can only add spacers if needed).
On the Simmer mast all my SCR rigs straight out of the bag, with no spacers needed on the recommended settings.
J
Of course, i will post pictures today..thanks a lot again :)
The pics below are from today. As you can see from the wrinkles in the foot i release some batten tension in the two bottom battens. How that seems to you?
Definitely too much camber tension. Either get the Simmer mast or you can file 2mm off the back inside edge of the cambers for a start. I would go for the right mast.
Select to expand quoteAUS4 said..
Definitely too much camber tension. Either get the Simmer mast or you can file 2mm off the back inside edge of the cambers for a start. I would go for the right mast.
ok thanks! i guess the rrd is more flex top than the simmer that's why. I will go for the right mast
Have you got any 430 RDM mast ? Most are the same diameter ..you could just buy 3 RDM cams for $20 each
top one doesn't need changing ...
but yeah photos tell you mast looks too fat .and you've got heaps of flap up top but none mid .
it still works for sure ,but we are fussy buggers ...
you will get better performance out of the right mast .or perhaps go down the RDM .road ..
7.0 needs a 430 7.8 a 460 and my 8,6 need a490 .which is a bugger ,but
I use a north SDM on the 8,6,I use a ezzy on the 7.0
and I brought a simmer RDM 460 for the 7.8 simmer ,seem it will be my most used .
got a smashing deal off sail repairs .
nice sail mate .
Having a second look at the sail the downhaul lines look pretty good ..pity about the rotation .
Select to expand quoteTardy said..
Having a second look at the sail the downhaul lines look pretty good ..pity about the rotation .
Thanks for your responses Tardy! Yes the curve of the rrd must matches the sails pretty good. The performace also is pretty good. I m gonna try teckam reduced with an rdm mast or try the original mast
Forget RDM you aren't sailing in the surf.
use the mast that was designed for the sail. 
Select to expand quoteAUS4 said..
Forget RDM you aren't sailing in the surf.
use the mast that was designed for the sail.
:)
Select to expand quoteSail Repair WA said..
Hi Alex
If you got any pictures when you have them rigged up, then it would be handy.
Just to see if the shape etc, looks the same as on the Simmer masts.
Yes the SCR comes without any spacers on the cam tongues (so you can only add spacers if needed).
On the Simmer mast all my SCR rigs straight out of the bag, with no spacers needed on the recommended settings.
J
How the sail look to you?
Sorry the late reply Alex,
Thanks for posting the pics, it do help to some extend.
If the RRD mast is more or just slightly more flex top, then it is not a good thing, as the balance between downhaul tension and the open leach will never be quite correct, and can also be a negative for the rotation.
In general with a little less downhaul tension ( than a constant curve mast) your top of the sail will open up to much, with a flex top mast, but the mid section of the sail from the boom end and up 1-2 battens, would be 'to closed'. Also with the little less downhaul, might make the cambers a little harder to rotate. You can't really downhaul more as the top of the sail will be to loose. I still think as pointed out before that the diameter could be different. Only 1-2mm cam make quite a difference on rotation.
I hope you can at least get the Simmer mast and rig the sail and compare, to see what improve.
The batten tension don't have to much to do with the rotation. Only a tiny bit and much less that most sailors think. Tension the battens so the wrinkles disappear in the sail. Most tension on the bottom 2 battens and gradually less all the way up from there.
There can be some cosmetic wrinkles that is hard to avoid in the bottom panels near the sleeve. This is due to a good amount of shape build into the sail in this area. This shape helps a lot on the stability / performance, so don't worry if those can appear.
To modify and cut/ sand the cambers down is not perfect, but can be done. I would not recommend it, especially knowing with the right mast that everything works great. If you do go for this option, then aim for the same rotation pressure on the 3 bottom cambers and a little less on the top one. You want them all to work together and flick around in one go.
RDM masts can be used. You need the Tek Cam for RDM. They are longer and will fit straight in. Some sailors prefer RDM and in some way the rigging and rotation of the cambers is more forgiving due to the reduced diameter. However I would always recommend the correct SDM mast, for 7.0 and up. Also the sails is designed on those masts.
Alsonote that most race sails 'set in a bit better' over some days on the water
J
Select to expand quoteSail Repair WA said..
Sorry the late reply Alex,
Thanks for posting the pics, it do help to some extend.
If the RRD mast is more or just slightly more flex top, then it is not a good thing, as the balance between downhaul tension and the open leach will never be quite correct, and can also be a negative for the rotation.
In general with a little less downhaul tension ( than a constant curve mast) your top of the sail will open up to much, with a flex top mast, but the mid section of the sail from the boom end and up 1-2 battens, would be 'to closed'. Also with the little less downhaul, might make the cambers a little harder to rotate. You can't really downhaul more as the top of the sail will be to loose. I still think as pointed out before that the diameter could be different. Only 1-2mm cam make quite a difference on rotation.
I hope you can at least get the Simmer mast and rig the sail and compare, to see what improve.
The batten tension don't have to much to do with the rotation. Only a tiny bit and much less that most sailors think. Tension the battens so the wrinkles disappear in the sail. Most tension on the bottom 2 battens and gradually less all the way up from there.
There can be some cosmetic wrinkles that is hard to avoid in the bottom panels near the sleeve. This is due to a good amount of shape build into the sail in this area. This shape helps a lot on the stability / performance, so don't worry if those can appear.
To modify and cut/ sand the cambers down is not perfect, but can be done. I would not recommend it, especially knowing with the right mast that everything works great. If you do go for this option, then aim for the same rotation pressure on the 3 bottom cambers and a little less on the top one. You want them all to work together and flick around in one go.
RDM masts can be used. You need the Tek Cam for RDM. They are longer and will fit straight in. Some sailors prefer RDM and in some way the rigging and rotation of the cambers is more forgiving due to the reduced diameter. However I would always recommend the correct SDM mast, for 7.0 and up. Also the sails is designed on those masts.
Alsonote that most race sails 'set in a bit better' over some days on the water
J
Thanks a lot J. Really appreiciate your thoughts and findings. I made an investigation though and i discovered that rrd 430 mast is 13.5% bend curve meaning that is as said progressive constant curve exact the same as the simmer mast which is also 13.5%. The problem must be with the diameter of the mast. Also the how the sail seems to you? The downhaul lines in the leech etc.. Anyway i should stick to the right mast ;)
I have found similar issues using the masts I had on my HSM on my SCR. I've ground back the bottom two cams and my sail rotates ok. I agree the leech appears to open up too early, but it still seems pretty powerful
