Has anyone tried the Maui Ultra Fins Delta? I need a round a 30-35cm fin for my JP FSW 107 to carry a 6.7 and am considering the delta wing 19 as I sail mainly in the river were it can be weedy and there are a few shallow spots.

go the 19 ive got a 17 and its to small for my 6.6 on a 112 and go the slalom not the speed it should be a more allrounder gd luck Tunes83

The 19 Delta is too small for my 6.6m with a Tabou Rocket 105. It's great with a 5.9m and 5.5m sail. They take a bit of getting used to and are not good in choppy water. However you can sail in very weedy and shallow water. The Delta fins inspire confidence in shallow, weedy waters.

i wouldn't use a delta unless your sailing shallow, if your sailing chop i would be looking at another fin, the delta fins are 55deg and way too much for chop, you don't need to go any more than 50deg, there are fins out there that claim there weed fins at 38deg and will work in light weed ,
keeping in mind with your 107 fsw and 6/7 sail and a 19 delta your board is going to be sitting much flatter in the water, for that gear your going need a fin with a bit of lift , in saying that the 19cm delta will drive you to windward in chop without letting go, but you wont get enough lift off the wind in chop and causing problems like catching a rail and the fin letting go because of lack of pressure ect
so Tunes83 if you can make any sense out of that bit of useless information your doing well

The main factor is how much chop you'll be sailing in. I'd much prefer sailing with a 40-45 degree fin in weedy waters unless it's really shallow and really weedy. Last week I was sailing in 35 knots and mirror smooth water and the MUF slalom 20 was absolutely rock solid on my iSonic 90 / 6.3m sail. I wouldn't have sailed on anything else (unless I had my speed board and 17cm MUF delta). I've sailed the same board / fin combo in 6 inch chop and it's been not so good. Any more chop than that and I'd switch to a standard weedy.

My iSonic 90 usually takes a 36cm fin, and the 20cm MUF delta slalom seems a pretty good match. I reckon your best bet would be the MUF 19 slalom if you usually use a 30-35. But it really depends on how choppy your river is. You might ne better off with a standard 45degree weedy and just avoid the shallow patches, or go the MUF delta and play in the shallows.

Agree that Delta fins don't handle chop well at all, but in their defense, when using, you don't so much as avoid the weed but completely ignore it's existence all-together! I have never met anything on Lake Illawarra / Primbee that has resulted in anything more than a slight tug from the delta fin, whereas my more conventionally raked speed-weed fin bogs down to a dead stop with weed wrapped around the fin every time on similar clumps. With a delta fin, as long as there's at least 25cm of depth, you can plow into the shallows with amazing confidence about not going over the handlebars.