T&T: BSP/NPT Fittings

[Larry N. Brown]

I have installed three O-1 GCF filters on Cigano, one each for the main
engines and one for the genset and at the moment, they're just sitting there
idle. I intend to plumb the whole system in with leftover SS 3/8 aeroquip fuel
hose and 3/8" fittings. Talked to the GCF people and they indicate that the
1/8" oil pressure or low oil pressure switch orifice offers plenty of flow for
the system. I need to put in a nipple, a T and a few other parts for the
pressure side of the system. All three engines are Yanmar and according to the
Yanmar people, the switches are 1/8" BSP. Great.

Now, this brings up some additional factors. There are BSP tapered and BSP
parallel threads. Anyone know which thread an oil pressure switch has?

I don't want to mess with the threads on the engines so I'd like to thread a
BSP nipple into the engine and go from there. Question. In order to assemble
this manifold, is it better to tap a BSP fitting for NPT thread or vice
versa?

Regards,

Larry and Teri
M/V Cigano, 47' Prairie Sundeck Cruiser
Lying: 64 Cypress Road
          Covington, LA