I think this issue has been posted before, I can't find the answers in the archives so I'm seeking some help with my problem..

I have a S&G Guillemot which tracks well and handles easily in wind and waves.
I've just completed a Guillemot 17 stripper. I loved building it but it seems to behave much differently in the water..

I can't make it go straight.. Also,when I let it glide, it veers to one side tracking a J ... This was in fairly calm water with a very light breeze from the stern. As the boat curls upwind there was a cavitating action at the stern.. ( This does not happen with the S&G.).

I tried moving the seat , No change.
I'm 180, the boat was not loaded..

If I need to paddle differently.... How so??
If I need to try a fixed skeg .. how big?? location??

Thanks to all for any advice.. Bewildered Terry

PS If I could post pics, You could all have a laugh at me doing doughnuts in the lake like a one armed swimmer!!!