Hi Derek,
Thanks for comments
The vid was shot very early on in the build, and as such the only ballast used was from the batterys, i think i made a post after the vid regarding the ballast as i calculated it would need around another 20kg, so the sound you heard is due to the hull sitting high so the prop wasnt fully submerged when rotating which as you mention, was drawing air. Im yet to do another wet test to determime the correct waterline/ballast which will be once ive primed/painted the hull.. soon!
The motor is from Mobile Marine Models, it was listed as 24v 12 pole, they no longer sell them i dont think, the actual rpm under load is around 3500-4000 without the need for any gearing, which is ideal for scale speed of my tid
i also have a similar motor but 12v but after testing both in my build, the 24v ran smoother, im running it on 12v. The motors i believe are what are used on electric wheelchairs and escooters!
As soon i get another vid i will post it, im.keen myself to do another wet test but i want to get the hull painted first