Hey SUPers.
I recently got a 7'9" Shroom and have been playing with fins. I want share the learning and hear from others. Feel free to add your experiences too!
I'm mainly a prone surfer riding shortboards in the 5' to 6' range, so SUP surfing is a small soft wave gig for me. At 53 and 70kg SUP surfing gets me in the water more often.
My local waves are anything from knee to double overhead, tending to the smaller end of that mostly, often windswell, but well shaped beach breaks.
I was in two minds on the Shroom, not sure about the unique fin setup. I'm a long time quad surfer, preferring the rear fins out on the rails. I find thrusters slow to get going with lots of drag. Would I be able to get the quick acceleration and loose turns with the back fins placed near the centre?
Here's what I've found with 4 different fin set-ups.
First, the fins it came with.
These are beautifully made, and the design is as uncompromising as the overall Shroom concept.
Front and back fins are close to the same size, with about an 1/8" difference in the base length. Like many Sunova fins I find them quite swept back. And they have a lot of area in the tip.
Ultimately they were too big for me.
In small or softer waves I could feel the drag, but they were surprisingly snappy when pushing the turns.
In waves with more energy the fins would generate a lot of sudden drive down the line, but I found I had to burn off the speed to turn it.
I really liked the idea of these fins and got to feel their drive and snap, but I would need a much smaller set. 
Next something very different!
I haven't ridden this board ,but the further back you put the rears the tighter it would be .
quads usually are looser ..depending on size ..7 fronts ,3 rears ...with the flow and placid .just keep trying different combos ..I'm going through that now ,with my new placid .
maybe try different sizes ...
The front fin is the Tom Carroll Aqua-line. These have a relatively long base, reasonaly standard sweep, but quite a fine tip.
The interesting bit is the fin has 6 degrees of cant built into the tabs, which added to that built into a board's plugs, results in somewhere between 12 to 15 degrees overall vs the more usual 6 to 9 degrees.
I've found in any board these fins have alot of drive, go rail to rail very easily, turn very precisely, and as a result surf really tightly in the pocket of a wave! But as waves get overhead and hollow they can create too much lift and get hard to control.
The rear fins are the common FCS G-XQ quad rears. Relatively small and upright sweep.
This set up really brought the Shroom to life for me. Quicker in softer waves, more control at speed and tight turns surfing off the tail of the board.
I could've stopped here and just enjoyed this set up, but there were a few more things to try....
Next up was MR twins. I've tried this set up in an 8'8" Speed and preferred it over a thruster set up.
These had the longest base length, greatest height and the most upright sweep.
I found these went really well in smaller or softer, less steep waves. The board was quick to get going, very skatey surfing off the tail, and covered a lot of ground in soft sectioning waves.
Where this didn't work so well was hard turns in steeper waves, with the fins losing grip and sliding a little, then recovering. Might try some really small tab fins in the back.
The MRs are further forward on their tabs, which might contribute to losing grip when pushed.
Overall a fun set up that is worth swapping to in small waves.
One more set up to post, which I'll load later.
Awe thanks for all that ^^...
I've a 7'6 and have only played around once with the fins and didn't like it (changed to my PCC7's off my Flow) so ended up back with the stock setup.
Which actually suits my bad back foot slash and burn efforts..
I'm going to try this out ^.
Cheers form the cold UK 
(and we have a shroom thread going already if you want to look at stuff we've been doing)
Select to expand quoteTardy said..
I haven't ridden this board ,but the further back you put the rears the tighter it would be .
quads usually are looser ..depending on size ..7 fronts ,3 rears ...with the flow and placid .just keep trying different combos ..I'm going through that now ,with my new placid .
maybe try different sizes ...
Cheers Tardy.
Yet to try the rear fins further back. But keen to try that.
I've found the smaller fins generally gave me more speed in very small waves and more control as the waves got bigger.
The final fins I've tried are C drives in the front with GQX in the rear.
The C drives have more base length than the original fins and much less tip area.
This was the best all-around set for me. Quick off the mark, lots of drive, good control and tight high speed turns.
While this will be my go to set up, I'll play with the MRs and rear fin position in different conditions. And maybe even asymmetrical rears.
yes ,that looks good ...I've got some c-drives coming ..and this is what i will be trying ..a bit of drive a bit of loose .
Fun posts, it reminds me of my life before the Quobba, trying many fins combos :-)
Seriously, try a set of Quobba, it will simplify everything, and you can then resell a lot of fins ...
WOW... those are old Cdrive's.
If you are wanting smaller Cdrive rears,contact Troy for Grom or XS ,he may have some of smaller sizes.
With the MR's , for something different, look at trying ZigFins for centers , 4 in smaller , 6 for bigger waves .
I'm mainly a shortboarder and newby to supsurf also. The shroom set up reminds me of Neal Purchase Junior Duo which I fn love, The board shots are 7ft, and the failed sea eagle shot is the 6'4". The fin configuration apparently is from the '70's and Neal tweaked the fins design. He hand shapes them and has rake on both sides. It's a drivey fast and loose board, goes vertical well, just google NPJ surfing them and you'll see.
7" long and a fixed position in the box, don't move 'em is the drum.
So Karl here's a thought for your fin fun times, go bigger in the back and stabilisers/nubs on the side (if at all
) ala bonzer and/or NPJ duo just for ****s and giggles. If you give it a crack let us know.
I plan to get a shroom for all the reasons you've stated when I get a handle on this gig
Hey Backbeach. Thanks for the idea!
The double single's been around since at least 1970 I hear.
www.swaylocks.com/forums/bill-thrailkill-you-owe-me-new-surfboard
Never tried one, until today...
The two singles are Salty Merchant twins. The sidebites are very small.
The waves weren't the best. Waist high onshore slop.
The board was very quick and turned ok in the flatter waves.
I didn't think this was going to work but there's definitely something to it.
I'll be trying this one out some more.
K
On such a board, I would be tempted to use a thruster set, but asymmetrically: use only one central fin in the toeside rear box.
Stoked for ya Karl-and me cos its only making me keener too. Those fins have a similar profile to Neal's, upright and not too much rake, look the goods. I meant to say the fins were foiled on both sides. The idea is a souped up single fin.
Speed is a feature of the duo, I'm often surprised how much ground I've covered by the end of a ride.
Dunno about assymetrical Colas with that big arse tail, assymetrical shortboard design usually involves the whole planshape/outline. But hey ya fins are only as far as the beach if you want to change them and as the saying goes, change your fins before you change the board.
Select to expand quotebackbeach said..
Dunno about assymetrical Colas with that big arse tail,
It works quite well, at least in small waves for me on a wide-tailed board. Above chest high I began to slide a bit too much on rollers, but it was definitively interesting: more drive ( = speed) on bottom, more release in top turns. The more centered boxes on the shroom should work even better for this than on my board:
Select to expand quotecolas said..
Fun posts, it reminds me of my life before the Quobba, trying many fins combos :-)
Seriously, try a set of Quobba, it will simplify everything, and you can then resell a lot of fins ...
Havent had it out yet but keen to try this set up, will push rears to front tabs thought i think...
I love the garbage bin board stand. It's my work stand of choice/convenience too!
Had the shroom out in very small but clean surf this am. First go with the Quobba's.... It definitely felt faster even in the small gutless swell and definitely a lot looser. May be too loose in larger surf. Overall I would say they are an improvement for me... ....
Hey Colas how does your assymetrical set up differ for lefts and rights, i.e. do you have to have the two fins on the wave face?
Looks like it could be wild transitioning rail to rail. I'll give it a go-on my shortboard at least!
Select to expand quotebackbeach said..
Hey Colas how does your assymetrical set up differ for lefts and rights, i.e. do you have to have the two fins on the wave face?
Looks like it could be wild transitioning rail to rail. I'll give it a go-on my shortboard at least!
I must say I only took frontside waves with this setup (the break was only rights, I am regular), so the two fins were on the wave face. Whether swapping sizes with the rear fin would have worked better on lefts is a very good question.
The waves were fast but small (hip high) and I was on a long board (9'3"), so I was looking for ways to loosen this long board while keeping the drive for making the sections. The added release on the top was not hard to handle on this wave size, I guess it could become tricky on bigger waves. One could imagine putting a nubster on the back heel side to mitigate.
Since then I have seen pics of people using a quad setup on the toe side, and a single twin fin on the back side, seems fun.
And Album & True Ames make a thruster with the opposite: one twin toe side, and 2 quads heel side, so you should test every setup:
www.trueames.com/products/album-asymmetrical-regular-futures-compatible
"The larger toe side fin will harness power and drive off the bottom while the two smaller heel side fins are meant for tight and responsive re-directional turns"
This setup may work also backside I guess. And is in fact the one that seems the most common in asymetricals.
I must say I did not try it anymore, as it was fun moving fins around in the water with the FCSII system (storing extra fins in the flap of the zipper on my chest zip wetsuit), but not so practical with the screws of the FCS1 system of the Quobba. And I cannot imagine going back to normal fins, even for a test :-)
Select to expand quoteKarlLQ said..
The front fin is the Tom Carroll Aqua-line. These have a relatively long base, reasonaly standard sweep, but quite a fine tip.
The interesting bit is the fin has 6 degrees of cant built into the tabs, which added to that built into a board's plugs, results in somewhere between 12 to 15 degrees overall vs the more usual 6 to 9 degrees.
I've found in any board these fins have alot of drive, go rail to rail very easily, turn very precisely, and as a result surf really tightly in the pocket of a wave! But as waves get overhead and hollow they can create too much lift and get hard to control.
The rear fins are the common FCS G-XQ quad rears. Relatively small and upright sweep.
This set up really brought the Shroom to life for me. Quicker in softer waves, more control at speed and tight turns surfing off the tail of the board.
I could've stopped here and just enjoyed this set up, but there were a few more things to try....
Karl, you are a good way with that combo of TC and G-XQ. My dime would be to swape The TC Aqualine which are a bit narrow base for the TC RED-LINE. It has been the best combo of fins I did use for years on my favourite SUP 6'5"27.75'' 85litres shorter board than your Shroom but with a similar outline
www.seabreeze.com.au/Photos/View/8761617/Stand%20Up%20Paddle/DSC03368/?m=3&p=Kami
The board in action finned with TC RED-LINE and G-XQ
