Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
I take it that the fresh water is being converted from the under sink jug to tank/s under the V berth. In doing so, a vent line will be part of that installation. I ran my vent line to the anchor locker opposite the ballast tank vent. If using a gravity fill... I will let the newer boats identify where Catalina has installed that.
If by some chance a wash down pump is also in your plumbing scheme, then I'd suggest considering forced filling using the wash down hose. One small bypass valve is added, with the gravity feed fill deck fitting and lines not needed. The tanks are observed to be full when the vent line discharges water into the anchor locker.
Holding tank deck plate can be on the horizontal surface of the coaming or angled thru the hull between the horizontal surface and the rub rail. I'd give some thought toward if a holding tank is ever intended down the road. If not, then the location is not very critical. If a holding tank is down the road... then take a look at the drawing to see where the probable deck plate would be in such an installation.
I'd like to add that threaded female (and even male) PVC adapters are not always "best" in a situation that has some flexing of the pipe and fittings.
I'd recommend using flexible PVC pipe wherever possible as that will take some of the shock out of the fittings.
Thick flexible PVC pipe in many ways is more durable than the standard hard PVC that most stores carry and in some situations (such as this one) I think it is far superior to use.
Flexible PVC that is the same thickness as standard schedule 40 PVC pipe is also known as "spa flex" because it is used a lot in hot tubs and jetted tubs.
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.