From floater to sinker?

50L is a semi sinker. Go for it.

Once you are up on the foil size is irrelevant. The challenge is getting up on the foil to start with.

I am assuming a knee start and not foot strap start:

You maybe highly skilled and able to simply hop onto the board on your knees and lift your wing up off the water and get going. I wing with a few folks that are able to do this. For me (110kg) on 45L and 51L boards I had to learn the stinkbug method to be able to mount the board and get the wing into a position to fly the wing. This is the first of three important steps you need to sort out.

The second is that your board will be somewhat submerged after you are on your knees and have the wing set. You need to get some forward movement to get your board to the surface so it begins skimming on the water surface. The challenge is not burying the front of your wing when you are lifting it and pumping it to move your board to the water surface. Maintaining your balance while you are pumping can be challenging when you are first learning. You do improve your kneeling balance with time and multiple starts. You will get some good forward speed once you get the board to the water surface and this is super important to assist in the pop-up.

The third is the pop up to your feet. I generally pop up onto my feet right foot first. Heading to my right, no dramas. When I head to my left, my right foot becomes the rear foot and popping up on such a small board becomes problematic. You need to practice popping up on the "leading foot first", it will make a world of difference. It also heaps to make it snappy (bit like a one movement surface board take off). Use the power of the wing to lift you up.

When I was learning, I used a larger than necessary wing to make it all happen and I already use a very large foil (2100cm2).
The surface area of your sinker/semi-sinker does make huge a difference getting to the water surface.

At 68kg i use a 5.0 75l , i started using the stink bug but ended up finding it way easier just to get straight onto my knees with the wing next to in the water to help balance then just pick the wing up and start from there.
I found for me with the stink bug in really choppy water my board was really tippy and if i started tipping i couldn't always stop it.
Would a lesser volume board actually be easier , less float and slightly under the water line?
Would i lose much low end?

Thanks all, looking forward to try it!
What's the stink bug? Is it the second technique in this video (turn on subtitles):

Bahahahahaha

The sinker I am mostly using is 51L 5'10" and my neutral board is 95L 5'4" .... Even though the 51L is longer, it is about half the weight and lot more fun to ride, turn, pump.

I am also using a 45L 4'10" and the fun level once up on the foil is even more so than the 51L or 95L boards.

I tried my 42.5 L board last weekend for the first time.

I'm about 80 kg and normally use an 89 L board.

All in all it went well. Got up and going second attempt and thought "what's all the fuss about?(maybe I'm just super skilled!)", did a few runs over and back then when I finally fell in, it took about 15 attempt to get going again! Lots of falling, but got several more runs. Went out again the next day with a little bit more wind and it was much easier (but still a lot of false starts).

My main advice:
1. Get the stink bug start nailed on your normal board first. It's fairly easy once you just commit to it a few times. Don't know how I would have done it any other way. Granted I was at the beach with lots of onshore wind chop - not the best learning conditions. There's a good thread on this forum with lots of videos. I start with knees across the board so the board is already pointing the right way.
2. You need plenty of wind or a bigger wing than you would normally use for the conditions, even if only for the first session or two. Helps you balance by using the wing to lift your weight and helps get the board moving and on top of the water.
3. Prepare to be humbled / frustrated like your first few sessions.

Hope this helps.

To the folks who haven't embraced the stink bug start method, try this: instead of using the leading edge handle, just use the front power handle. Having the front power handle in your hand before you get on your knees (whether sitting or laying across the board) eliminates one step where you are the most unstable. It has sped up my take-offs immeasurably. Just pretend you no longer have a leading edge handle. It's so efficient.

I got the sinker bug now only took me a couple of sessions to get the hand of knee water starts.

Couple of lessons learnt:
* It's easier than you think it is. Just need to commit !
* DON'T use a 4m when you think you can.... 99% you won't have enough power to get going even though everyone else is on 4/5m. Always assume 6m unless hopelessly overpowered.
* Use the wing floating to lean your hands on top when positioning your knees
* Turn around your harness hook before mounting the sinker then turn back in front when kneeing on it
* You need a full traction pad. I kept slipping off where I don't have a pad between front and back
* You crash a lot less with a sinker. Not sure whether it's because you're more focused not to crash and/or a sinker touches the water less.
* Pumping is next level with a sinker
* Forget the waist leash, a calf leash is heaps better. And yes you'll get some sore skin marks from it initially at the bottom of the thigh from the kneeing.