Thanks alot everybody. I have now opened up the transom hole to allow the strut to slide 5mm up and down in the bracket.
I start like this and when I get the boat to track without bouncing I silicone it up.
Dave: Here's the source of my confusion. I followed the enclosed printed instructions I got with the kit, that's why I couldn't figure out how to make the strut adjustable.
..... Sorry for being an idjiit but this boat things are new to me and there are two contradicting instruction set's.
Included, printed instructions: (This is what I did)
...Drill an undersize hole for the prop tube, Enlarge the hole until the tube just fits through it. Seal the tube exit...
Sigma web page instructions: (...And this is what I now have done)
Drill an oversize hole for the proptube...After first tests seal the tube exit through the transom with silicone tube or silicone sealer.