"working a new one atm of a pt 109 boat, powerd by a jet motor like the origional design."
Sorry Staffros, but I think you've got your wires crossed somewhere🤔
The PT Boats were never fitted with water jets.
As far as I know water jets hadn't even been developed in the 1940s.
PTBs were driven by 3 conventional shafts and screws powered by Packard engines.
You may be thinking of the PBR (Patrol Boat River) as used in Vietnam.
Otherwise known as Pibber.
As I am restoring an old wooden PTB, and rebuilding as PT109, I have done considerable research on the PTBs. Mainly ELCOs like 109.
Here's a couple of basic links to illustrate what I mean.
There are plans and kits for the PBR on the market, and some examples of models here on this site.
Cheers, Doug 😎