Let's Talk Marine Wire

Within days of Pilgrim arriving in Beaufort, Feb. 2014, we removed all of the existing wiring.

Creative and dangerous wiring in Pilgrim's bilge.

34 years of modifications and repairs to the electrical system by many hands left a hodgepodge of wiring.  Almost all of the wiring was sub-standard.  Some was outright dangerous - note unfused bilge pump wire run joined with wire nuts in image above – YIKES!

Unfortunately Morgan Yachts did not use marine grade wire in the original construction.

Factory installed shore power circuit breaker removed from Pilgrim.

So all the original wiring was also removed.

Gutting the original electrical panel.

All the wire going back into Pilgrim is marine grade.  So what makes marine grade wire different from home or automotive wiring?

• Marine grade wire is composed of tiny copper strands.  The wiring in a land based structure is typically a single thick copper wire. Stranded wire has more flex.  This allows the wire more easily fit into the tight spaces on a small vessel while placing less stress on connections.
• All the tiny strands of copper in a marine grade wire are tinned (plated with tin.)  The tin coating protects the copper from corrosion due to moisture and heat.
• The plastic insulation covering the exterior of marine grade wire is designed to resist degradation if exposed to fuel or oil.  This is very important for wiring in bilges and engine compartments.

What about the size of the wire (yes it does matter – haha.)  Size of electrical wiring here in the USA is designated by the American Wire Gauge (AWG). Wiring on marine vessels can vary from tiny 22 to 26 AWG in electronics and NMEA backbones to 00 (2/0) or 0000 (4/0) AWG wire in high amperage wiring for starter motors, windlasses, electric winches, etc.  Typically wires equal to or less than zero are referred to as “aught” (e.g. 2/0 is “two aught” and 4/0 is “four aught”).  

Wire must be properly sized based on type of current (AC or DC), voltage (12, 24, 120, 220), load current required (Amps), and total length of circuit (Feet).  If you are looking for more information, I recommend Blue Sea Systems: Choosing the Correct Wire Size for a DC Circuit.

The article above is the source for my preferred 12V DC Wire Sizing Table.

The sizing chart does not tell the entire story.  Each wire size also has a maximum ampacity. 

Ampacity is defined as the maximum amount of electric current a conductor or device can carry before sustaining immediate or progressive deterioration.

Thanks to Wikipedia for the speedy definition.  Factoring a wire’s ampacity and fusing wire runs accordingly is critical in primary wiring (i.e. feeds to battery selector switches, to electrical panels, to ground bus, etc.) and wiring for high amp components (i.e. starter motors, windlass, electric winches, etc.)  Here is a handy chart for maximum ampacity.

Choosing the correct size wire and fusing it below its rated ampacity is critical for the proper functioning of on-board systems and for the safety of all aboard.  I’ve printed both of the tables above and keep them handy in a plastic sheet protector when working on electrical systems.

Hope this information is helpful.  If anyone reading this post feels the information is stated incorrectly or it is misleading please let me know via a comment. 


I’m in full support of boat owners getting dirty and tackling their own projects, but if uncertain when assessing, altering, or installing electrical systems in your vessel please seek professional assistance.

Plumbing Bilge Pump Discharge Hoses to Drain Manifold in Cockpit Locker

Last September we installed three electric bilge pumps in Pilgrim (see – Installing Electric Bilge Pumps.) The two pumps located lowest in the bilge discharge to the drain manifold in the aft portion of the cockpit locker.   The Morgan 382, 383, & 384’s designs have a unique drain system. If you are unfamiliar with the system check our July 30, 2014 post – New Deck & Bilge Pump Drain Manifold – for more info.

The discharge hoses for the lower two bilge pumps run up from the bilge to the area under the galley sinks.  Next they pass under the stove and under the ice box before reappearing along the foreword bulkhead in the cockpit locker.

Bilge pump discharge hoses run vertically along the new cockpit locker bulkhead

To prevent possible back flooding the discharge hoses must run to a siphon break located at point in the vessel that will remain above water level in all conditions.  We chose to install the siphon breaks in the hollow interior of the port cockpit combing.

Two siphon breaks mounted in stacked formation.

The siphon breaks are stacked vertically. The lower, 300G/H, pump requires a ¾” id hose.  The middle, 2000G/H, pump requires a 1-1/8” hose.  The middle pump discharge hose diameter is increased to 1-1/2” at the siphon break and continues at the larger diameter for the remainder of the run to the drain manifold.  90 degree elbows (pictured above) keep the hose runs compact, but elbows decrease the flow and can create back pressure that will reduce the effectiveness of the pump. Increasing the size of the discharge hose on the downstream side of the siphon break allows for the use of elbows without creating back pressure on the pump.

Earlier in cockpit locker refit we installed a ½” panel along the inside of the vertical cockpit seat back.

Purpose of panel along inside of port cockpit seat back is for mounting hose and wire runs.

The sole purpose of this panel is to provide a mounting surface for hose and wire runs.  We used sections of the retired aluminum angle from the salon (Aluminum Angle Brackets In Salon) to attach the plywood to the forward bulkhead and to panel we installed on the aft wall of the cockpit locker.

Siphon breaks and hose runs viewed from aft looking forward.  Hose on left is port deck drain.

Downstream of the siphon breaks the hoses remain elevated across the length of the locker. Upon reaching the locker’s aft wall they drop down to the drain manifold.

Drain manifold from left to right:
1-1/2" black hose is discharge for secondary 2000G/H bilge pump
3/4" black hose is discharge for primary 300G/H bilge pump
1-1/4" white hose is gravity fed port deck drain

More images and notes from this on-going project are available in the Cockpit Locker Refit Photo Album

Installing Electric Bilge Pumps - Bilge Modifications Part 2

If you missed the initial post in this series here is a link back…“Bilge Modifications – Part 1”

After allowing the lower bilge, formerly the holding tank, over a month to air out and dry, we returned to paint both the upper and lower bilge.  The paint prep began with a TSP (tri-sodium-phosphate) scrub down and rinse.  This was followed by some very awkward one arm, blind sanding.  Once the surface was prepped we applied four coats of Interlux 2000E barrier coat to both upper and lower bilges.  The upper bilge then received a couple coats of white paint. 

Looking down into the freshly painted bilge.

Next step… install bilge pumps.   

Save for needing one 12V Ultra Safety System Pumpswitch Jr.  (anyone out there have one to spare?) we were able to construct Pilgrim’s new bilge pump system from  equipment on hand.  The system is comprised of one manual and three electric  pumps.  The manual, Henderson Mark V, will be installed in the cockpit.  The three electric pumps will be installed in the bilge at differing elevations.

Elevation diagram of Pilgrim's three electric bilge pumps. 

 The daily use pump, smallest capacity and lowest float switch, is a 300G/H Jabsco Diaphragm pump. This pump is mounted under the galley sink.  The float switch & pick up line are mounted in the lower bilge on bracket fabricated from starboard.

Bracket for mounting lower pump pick-up and float switch.

The foot of the bracket rests on the floor of the lower bilge and the top flange of the bracket attaches to the floor of the upper bilge via a couple screws.  This assembly is mounted aft in the bilge with the scrum box resting at the forward end of the lower bilge.

Filter for diaphragm pump on left.  Discharge hose for middle pump and wiring for lower float switch on right.

An inline screen filter for the diaphragm pump is mounted on the cross brace just below the cabin sole

The next bilge pump in elevation is a 2000G/H Rule pump.  The Ultra Safety System’s Pumpswitch mounts directly to the bilge pump.  The float switch for this pump is also tied to a high water alarm.  The pump & switch are mounted approximately 4” above the floor of the lower bilge on a bracket made of starboard.

mounting bracket for middle bilge pump & float switch.

Like the first bracket the foot rests on the floor of the lower bilge and the top flange screws into the floor of the upper bilge.

Middle bilge pump installed in lower bilge.  Base/screen for upper pump is mounted in upper bilge on right.

The top flange on this bracket serves as a base for the upper, 3700G/H Rule bulge pump.

Upper bilge pump installed.  The middle and upper pumps have not yet been fully wired or plumbed in this image.

This assembly is mounted at the forward end of the bilge with the discharge hoses running aft.

Looking down into lower bilge with all the pumps, switches, wiring, and plumbing installed on the lower two pumps.

At present, I’ve temporarily wired the lowest pump to the starter battery and run the discharge out the galley sink drain sea cock.  This set up will deal with the small accumulations of water that find their way into the bilge.  Once we get further along with installing the new electrical system, then I will finalize the wiring.  Plumbing the discharge hoses will likely wait until after the engine install.

For additional images and notes check out the Bilge Modifications Photo Album. 

They Just Do Not Make Them Like They Used To...

Each time we shed fresh light in a dark recess or remove a cosmetic facade to reveal Pilgrim’s structural underpinnings, I find  myself muttering the clichéd line, “They just don’t make them like the used to.” They would be Morgan Yachts and them is sailboats.  

My comparison is between our 1966 Morgan 34

C'est la Vie - 1966 Morgan 34 

and our 1979 Morgan 382.

Pilgrim - 1979 Morgan 382, Hull #115

Now I’m sure the heart rate and blood pressure of some Morgan 382 owners and admirers out there is on the rise, but hear me out. 

I do not feel that the Morgan 382 series is poorly designed.  I am aware that most of the 382's commissioned are still on the water and include hulls that have crossed oceans and circumnavigated the globe. I remain very eager to get Pilgrim back to the water, cast off the dock lines, and point her bow towards the horizon. 

BUT…  It is obvious to me that during the construction of the M382s corners were cut.  My best guess is that the issue lies at the intersection of three factors.

1. Apathy on behalf of hourly workers cranking out 50?, 100?,  or more?  vessels each year.
2. Pressure on the construction team to speed up production to meet market demand.
3. Efforts to maximize profits by keeping fabrication costs in check.

Ok, thus far my rant is simply opinion and conjecture.  Allow me to share our latest discoveries on Pilgrim…

ONE...

Working in the bilge, I noted that the cross brace under the sole that links the partial bulkhead forward of the galley countertop on port with the partial bulkhead  just forward of the nav station on starboard was only tabbed to the hull on the forward side.  

Cross brace under cabin sole lacks tabbing on aft side.

Feeling the tabbing was inadequate, I added a couple layers of 1708 cloth tabbing to the aft side of the brace.

Tet fitting 1708 cloth sections along cross brace.

Tabbing installed along aft side of cross brace.

That evening I reviewed an image of the original construction plans for the bilge.

Original construction plans call for tabbing on both sides of cross brace.

In the original plans the brace is tabbed on both sides.

TWO...

Early this week while removing bottom paint along the starboard forward hull, I discovered vertical cracks in the gel coat.  Grinding the area out revealed damage that closely resembled that on the port side where the head pan settled directly on the hull.

Upper right area is remarkably similar to damage discovered under the head pan on opposite side of hull.

After grinding out the area, I went inside to investigate and discovered the cracks are directly under an un-tabbed section of  bulkhead. 

Glowing area below bulkhead in closet reveals location of damage on hull exterior.

Direct pressure from the un-tabbed, lower section of the bulkhead is the cause of the cracks and subsequent water intrusion.

Woven-roven tabbing along the bulkhead stops few inches above the waterline. 

The tabbing along the aft side of the bulkhead stops just above the waterline.

Forward side of bulkhead lacks tabbing along it's entire length.

The forward side of the bulkhead lacks tabbing along its entire length.  Minimally internal bulkheads should be tabbed on one side wherever they make direct contact with the hull.   Ideally the bulkheads are tabbed for their full length on both sides.   

All the bulkheads in our 1966 Morgan were tabbed on both sides along their entire length.  When Pilgrim returns to the water her bulkheads will also be tabbed along their entire length. 

I’m headed back to the boat to soldier on while muttering, “They just don’t make them like they used to.”

Bilge Modifications - Part 1

As I discussed in the Installing A Holding Tank In The Head post,  the original Morgan 382 design placed the holding tank below the bilge in the aft lower section of the keel.  Below is a blueprint of the area from the original plans –

Blueprint of the aft lower keel on a Morgan 382.

Pilgrim developed a leak between the floor of the bilge and the holding tank area.  I learned from the Morgan 38 Message Board, that other M382 owners have dealt with similar issues.   

My best guess is that the bilge floor leaks around the plumbing fittings.

Floor of bilge is perforated by plumbing for the holding tank. From aft (left) to fore (right) - PVC pipes serve as inlet and outlet for waste, grey tubing is holding tank vent, and plug with wires is sensor that indicates tank is over 3/4 full.

The new holding tank installed in the head eliminates the need for an inaccessible void in the lower keel.  I prefer to have access to the area to permit visual inspections and allow Pilgrim’s bilge pumps to properly eliminate all standing water inside the vessel.

I began by drilling 3/8” holes to serve as an outline the area to be removed.

Drilling 3/8" holes to mark the perimeter of the section to be removed.

While drilling the holes, I realized that creating a series of drilled holes would generate less fiberglass dust than other either using a jigsaw or a grinder with a cut off wheel. 

Series of holes complete.

The excavation did ultimately require a combination of drilling, jigsaw, and finally grinder with cut off wheel…

Working with power tools in the confined space with limited access required patience.

Eventually the fiberglass bilge floor succumb to my efforts.  I will spare you the image of fiberglass dust floating atop the black water below and the details of using a shop vac & scouring pads to clean the area.  If you want all the images check out our Bilge Modifications Photo Album.

I was not expecting the floor to be a consistent 1/2" thick.

 The consistent 1/2”+ thickness of the bilge floor surprised me.  The thickness of the material leads me to believe that it serves as a structural member of the aft section of the keel.   Good thing I only removed a small section from the center of the floor.

The source of the leak never revealed itself.  I’m still betting the leak existed around the PVC pipes that served as the inlet and outlet for the waste.

I believe the PVC pipes were the source of the leak(s)

Pilgrim now has an upper and lower bilge area.

The upper and lower bilges are now clean and dry.

Our plan is to allow a few weeks for the lower section to completely dry out.  We will then apply barrier coat, paint, and finally install bilge pumps & float switches.