I have been surfing all my life. Started using a SUP about 3 years ago. What I am using is a Fanatic 9'0" 159l. I am going to buy a new board and thinking of dropping volume. Maybe a Naish Maddog x32 145l or something like that. I am 61 years old and 100kg and surf just about every day. My question is how many litres of volume could I comfortably drop? Is 15 or 20 litres ok? I live remote and won't have a chance of testing any boards.
Neutral buoyancy would be your weight (100L). I'm 250 lbs 53 yrs old and been SUP surfing 15+ years and would say I'm moderately athletic and an intermediate surfer. I'm comfortable at 1.32 guild factor (weight in kg divided by board volume in L) on my 9'1" Sunova Ghost (pulled in nose and wide-ish tail). I'm really stable at 1.5 GF on my 10' Sunova One (full nose). The One is for the small days or when I'm tired/not having a "good balance" day. I mainly surf beach breaks with lots of chop and side current.
Board shape plays a huge part - eg a fuller nose/tail is much more stable than something with a pulled in nose/tail. Board width is also key; I had an L41 ST (8'4"x31"x136L); it floated me fine but I am more comfortable at 32" or wider.
It also helps to stand with a narrower stance and staggered (eg left foot forward if you're regular - a modified surfer stance). Sone people also say they sit between sets and get up to catch the wave. I'm not quick enough for that so I stand the whole time. I thinks fins have a part too; more surface area means more stability and vice versa. Gotta find the balance between stability and surfability though.
You're gonna see a variety of answers - I'm sure I could go less volume but don't want to fight it between sets.
yo ,yes the Maddog is a good choice .32 wide easy .145 litre ,you should be fine on that board .every board is a learning curb
The starboard 8'8 spice is also worth a look also 32 wide .140 litres ,9.0 x 144 Sunova flow .8'10 ghost .all in your range .
I' m also 61 and 100 kgs ,I have worked my way down to a 8'8 flow x 31 wide 126,3 litres ,but am finding 130 litres is my comfy zone
but still like the 8'8 size as it is nicer to ride than a 9,0 or I should say easier to turn being shorter .@ 31 wide you will find most of the time a narrower board below 32 wide will feel more zippy on a wave .if that's what you want of looking for, more of a performance board ,I don't ride 32 wide boards because they do feel big to me now .I think a 8'8 length will improve your surfing ,I like to ride boards no shorter than 8'8 now I just find them too hard to catch waves on for my weight ..and age 
You have so many board to choose from ,but if you are going to keep your 9 footer go for a 8'8 with good litres .you will love it .
enjoy the search .going to your question .litres .135-140
My friend is about your size and he tried to use that mad dog to progress into the surf. He was able to paddle it without much experience so I would guess stability wise it would be ok for you. However my impression of the board from watching him is it needs a bit of push from the wave and a little more aggressive riding style. If you don't have consistent access to decent waves or want a fast board you might want to try something else. I agree with tardy those are reasonable volumes 140-145.
Select to expand quotecqclay said..
I have been surfing all my life. Started using a SUP about 3 years ago. What I am using is a Fanatic 9'0" 159l. I am going to buy a new board and thinking of dropping volume. Maybe a Naish Maddog x32 145l or something like that. I am 61 years old and 100kg and surf just about every day. My question is how many litres of volume could I comfortably drop? Is 15 or 20 litres ok? I live remote and won't have a chance of testing any boards.
Hi mate, the Naish Maddog 9x32 145l was my first wave sup, It was nice and stable I felt like I could paddle into any wave and it surfs ok. The thing that I thought held it back was the width of the boards tail, makes it super stable, but you really need to get right back on the board for it to turn.
That was only highlighted to me went I jumped to a SMIK Hipster Twin, 8'6x 31.5 @ 134l. The much smaller tail of this board is a total different feel to the Maddog. The area in the nose of the SMIK still gives it plenty of stability and it's a board I can surf for hours in any conditions. The ten odd L differences between the boards was not a problem and I was really worried that it would be.
I should mention that we are both very close in size and age, I am 58, 100 kg or close to it and around 6'2.
I also have brought a SMIK Bonza in the 8'8 x 31 at 125l. Now I'am not sure if it's the lower volume or the Bottom shape and the outline of the Bonza, but its a lot more challenging to stand on out the back. I really feel it after surfing it for a few hours, but the performance of the board makes that an acceptable trade off.
So for me at the moment the volume in the 125l to 135l range is my sweet spot, so any board that I look at in the future will be in that size range.
Tardy mentioned the Spice 8'8 x 32 and if you want a little extra volume over the two SMIKs I have that would be a good choice as its tail is still narrow for its size. So it should perform better than the Maddog.
I would have either of my two SMIKS as an only board, but as I have said before you don't play golf with one club so why only have one board 
If you surf smaller waves mainly, the Hipster is king, and it will still handle any size wave you would like to paddle into. The Bonza wants a wave with a little more curve in the face to truly come alive. I love riding either board so I am happy with my choices at the moment.
Hope that helps.
Steve.
Thanks everyone. Plenty of food for thought. I surf 1 to 4ft clean, fast, steep reef breaks most of the time. I get in to Perth for a couple weeks in November so hopefully have something sorted to pick up then. Cheers.
I'd be looking at dropping the litres or volume out through going thinner on dimensions.
I find that the wider board the harder it is to manoeuvre around.
135-140L
Try 29 inches wide but keep the length.
Select to expand quotecqclay said..
Thanks everyone. Plenty of food for thought. I surf 1 to 4ft clean, fast, steep reef breaks most of the time.
In these conditions, you will see big benefits by dropping volume, especially in the rails.
It will make the board feel much safer to handle in hollow sections.
You will feel in control instead of being "along for the ride".
Not worth going for less than 130l however.
And in clean conditions, stability will not be an issue.
Especially if you go out every day.
I agree that you do not need to get down much in length. 8'6"+
I am not convinced in going too narrow (less than 29") however. Some width allows to spread the volume and make the rails thinner. In my opinion narrow rear sections and thin rails is what is important in fast & steep waves, some width can be kept in the center and a bit forward for noticeable comfort for us not-young-anymore without too much drawback.
