The two cockpit drains are large and are designed to drain the cockpit oh seawater from a wave.  The drains drop straight down and then turns almost horizontal to large check valves and then vertical through seacocks.  These are in the back corners of the engine compartment in front of the aft bulkhead. When we first got our 49, I was washing the cockpit while on the hard and noticed the drains slow.  The check valves were clogged with dried mud.  It took a hose from the bottom and plunger from the top to loosen dirt and free drain.  If you are in the water, try tapping on the check valves.  I could not open the check plug to access the inside.  In the water you should be able to run water from a hose directly down the drain and not overflow back on the floor.  We made it a point not to flush anything but liquid down the drains.
Hope this helps.

J W Eads
Over Budget
H49-16

The hull # -16 on our H49 puts it in the same vintage as your 49.  We have a single deck fill on the starboard side.  This 1 1/2" pipe drops down in front of the freezer and turns forward and runs on the top edge of the fuel tanks.  This pipe feeds both tanks through 1 1/2" fittings. You have no control which tank you are filling and once you get to the top 2", they are acting as one.  We lived aboard for 8 years, going from Nova Scotia to the Caribbean and I filled using the deck fill.  I did fuel below at first, but found that cumbersome.  I do not have gauges.  It helps if you have a pretty good idea how much it will take to fill your tanks.  I do this one of two ways.  Starting with full tanks we use 1 1/2 gals per hour at 2500 rpm.  If your hour meter says 20 hours - 30 gals.  Tell the dock hand to let you know when you have taken on 25 gals. and then listen carefully at the deck fill as you are fueling.  You will hear as the diesel starts up the fill pipe and stop the flow.  You or your mate cannot be chatting with the dock hand as this is done.  Practice this with the water fill an you will get used to the sound of the liquid coming up the pipe.  The tank vents are led to the stern lazarete and turn down into the top of the fiberglass tube that is connected to the stainless flange for the engine room blower near the top of the sugar scoop.  If you are concerned  about pushing fuel out the vents, put some paper towels in the tube to catch any small amount of fuel  that might exit here.  This only happened to us once.   The second way of knowing how much fuel you have used is by measuring the depth in each tank.  The stainless dip sticks ae impossible to read.  I pull the one floor board that exposed both dip sticks.  I use two layers of paper towels laid on the floor and held in place by blue masking tape.  Pull stick up, wipe dry and dip again an bring up an lay on paper towels.  Measure from bottom of top cap to wet spot on towel.  I carefully measured my tanks and created a chart to show depth versus gals. used.  I won't go into the chart since everyone probably stopped reading half way back.   
J W Eads
"Over Budget "

The drawing is on the boat on Trinidad and I am in Ohio but I provided my rendition here, looking from the back or front. His drawing showed a nice fairing between the skeg and hull but in reality it is a sharp angle. Don't know how long it will take to fix. The skeg feels solid with the rudder in place but moves in relation to the hull without the rudder installed. JR

I've noticed recently that there are a slew (30+) Hylas' for sale - especially in the 54/56 (10) class. Search Yachtworld. The last time I saw this many for sale was 2010-2012 when the economy was in terrible shape and no one was buying boats of this class. Right now the economy is in great shape. So I'm wondering, is it...

The brand? - The next generation of the family is now running Hylas. They are releasing a power boat (from Aus) and a new 57 aft-cockpit sailboat. When I visited them at the Newport boat show you could barely get their attention. They were very young, obviously not sailors and spent most of their time staring at their phones - they seemed way to shy to be working a boat show.

Monohulls? - "Leaners" as my cat friends call us are being taken over by people who love cats. My wife likes cats too but Flying Lady our H54#28 w/blue hull and teak rail, to us, is just beautiful, while large floating pieces of white plastic are less so.

Generational? - I'm reading that there's not a net growth of people who are into sailing. Older sailors go power, or stop sailing as it can be quite active lifestyle, younger sailors are chartering, getting cats or not wanting to put money and time into a large sailboat.

Coincidence - Is it' just by "chance" that there are ten 54s and 35 world-wide Hylas for sale?

We absolutely love Flying Lady. We just had a refit in Charlevoix, MI. Tomorrow at 5am I drive up there to begin a summer cruise throughout the northern Great Lakes. So we'll be enjoying her as long as we're able to.

Yan and Judy

Thanks for the suggestions, i ended up replacing it with a Belmar 614 regulator instead as that model is programmable