“Waking the Dog”
Some systems and devices on a boat are easy to take for granted, but ignoring them can cost you.

By Frank Lanier
Chesapeake Bay Magazine January 2003

“Let sleeping dogs lie” may be a perfectly valid watchword in some situations, but it has no place in the vernacular of boat maintenance. What marina barkeep hasn’t heard the tale of woe from a boatowner who has had those dogs wake up and take a bite out of his behind—and wallet? I guarantee that an out-of-sight-out-of-mind maintenance philosophy toward your boat’s systems will eventually earn you that unexpected and often untimely chomp. Here are my top six sleeping dogs—those for which you should routinely set an alarm clock.


Considering the excitement and havoc a failed seacock can generate, the lack of attention they generally receive is almost criminal. According to the American Boat and Yacht Council (ABYC), a seacock may have either an integral flange that is attached directly to the boat’s hull, into which a through-hull is threaded, or a valve attached directly to the through-hull. Many boatbuilders believe the former is by far the sturdier installation, but in either case, ABYC standards require it to withstand a 500-pound load for at least 30 seconds. Ball valves are the preferred type; gate valves are notorious troublemakers, whose potential for mischief is compounded when they’re below the waterline. Not only are the worm gear and associated guts of a gate valve prone to corrosion and failure, it is also possible for trash to prevent the gate from closing properly. ABYC standards also require that a seacock possess a 90-degree arc of operation, which allows you to look at the handle and see whether the valve is open or closed—something impossible with a gate valve. So the first thing to look for is the type of valves in your boat. If they’re gate valves, replace them.

Continue your inspection with the through-hull, examining it for leaks, cracked or broken

bedding seams, properly sized backing plates and electrolysis damage (bearing in mind that bright, shiny bronze fittings may indicate galvanic corrosion). Then move on to the seacock itself, beginning with a good visual check for anything unusual, such as leaks, corrosion, damage, missing components (handles, for example). Be wary of installations that employ a short piece of pipe between the seacock and the through-hull; the pipe introduces a potential failure point and should be removed as soon as possible. Open and close the seacock valve, making sure it moves smoothly and that you have room to manipulate the handle. (Don’t laugh—it’s not unusual for seacocks to be installed well before surrounding bulkheads or cabinetry that can impede proper operation.)

If the boat is out of the water, remove the hose and look through the seacock to verify operation and spot any blockage.

Another option is shining a flashlight into the through-hull from the outside and observing its operation while someone inside opens and closes it. Inspect all hoses, making sure each is double clamped (with stainless steel clamps) where possible. Gently tap securing bolts and the gland, or body, of the seacock itself with a light hammer or rubber mallet to test for tightness, corrosion, cracks or casting flaws. (Never perform this test with the vessel in the water, just in case something does give.)

Maintenance should include monthly exercising of the valve and a good greasing at least twice a year. Completely remove seacocks for disassembly and inspection every four years, which also ensures that you’ll be renewing the bedding compound when they’re reinstalled.

Plastic Through-hulls

When it comes to causing excitement, cracked plastic through-hulls are right up there with leaky seacocks. They’re often located at or near the waterline, so obviously you will want to pay particular attention to them. Ultraviolet light is the main culprit here, and while different brands vary widely in their susceptibility to UV damage, some are so poorly made they fail within a year or two. Manufacturers began adding inhibitors to second- and third-generation fittings to make them more UV-resistant. The problem is, you can still find the older materials on the market, and it’s hard to tell one from the other. So my best advice is to view all of them with suspicion.

These through-hulls commonly fail where the body of the fitting joins the

outer flange. The stress of supporting a hose that bounces around can cause cracks here, so try to secure hoses. Plastic fittings should be inspected at least annually. With the boat out of the water, look into the through-hull from the outside for signs of cracking. After you’ve eyeballed it, insert a wooden dowel or screwdriver into the through-hull and carefully apply moderate pressure at various points around the entire fitting. If you find one fitting that’s bad, play it safe and replace them all.

Cockpit Drains

What, you ask, can possibly go wrong with cockpit drains? The water disappears and everybody’s happy, right? Maybe. Let’s say your boat was built in 1980. Chances are the cockpit drain hoses are original, meaning the safety of you and your vessel hinges on a 23-year-old piece of hose.

First you should visually inspect the entire system, from cockpit drain to discharge through-hull, noting any leaks, splits or cracks in the hose or fittings. Is the hose double clamped with stainless steel clamps at both ends, and are seacocks used? The answer to both questions should be yes. Some boatbuilders, if they think the discharges are high enough above the waterline, omit seacocks on discharge through-hulls. You should verify that these remain well above the water all the time (whether heeling or planing, for instance), and install seacocks if you have any doubts. Inspect all hoses carefully for signs of deterioration, kinks or chafing. In colder climes look for hoses to be split or pushed off hose barbs, which can be caused by expansion and contraction during the freeze and thaw cycles. Heat and vibration can generate similar problems.

Electrical Systems

After years of additions, removals, misguided McGyverisms and overall abuse, no system onboard harbors greater potential for starting a fire than your vessel’s electrical system. The ABYC has excellent guidelines for electrical installations and systems, and its Standard E-8, AC Electrical Systems, is chockful of information.

For DC systems, begin by inspecting the batteries. They should be in liquid-tight, acid-proof containers that are properly covered to protect accidental shorting if someone happens to drop a tool or other metal object on the terminals. Make sure they’re properly secured and ventilated. Problems with loose or corroded battery cables are common, as is the slipshod practice of wiring devices directly to the battery. This is at best a bad idea and at worst a bona fide fire hazard. Make sure all your equipment is powered via an appropriate circuit breaker and fuse panel.

If your boat has an AC system, verify that it’s completely separate from the DC system (with shared grounding being the lone exception). Bad juju abounds for those who make the mistake of, say, connecting the neutral of the AC system to DC ground. Before inspecting your AC system, turn off all breakers (including the dock breaker), unplug the shore power cord and disconnect any DC to AC inverters you may have from the battery. Start your inspection with the shore power cord. It should be proper marine-grade with a water resistant molded vinyl cover and appropriate wire size. The cords you buy at most chandleries are usually No. 10 AWG three-conductor wire and come in various lengths. Always use the shortest cord that will get the job done, and replace chafed or split cords or those cocooned in electrical tape repairs.

The wire connecting your boat’s shore power inlet to the AC panel must be at least No. 10 AWG (that is, 10 gauge or lower) if it’s more than 10 inches long, and it should have an approved in-line fuse or breaker. Inspect AC and DC system panels for problems like charred terminals, broken wires or exposed conductors. Check the breakers and fuse holders, and ensure everything is tight and secure. Neaten up wiring behind the panels with plastic wire ties; the split conduit you find in automotive stores works well too. All connectors should be crimp-on ring terminals, preferably the type with attached heat shrink tubing. Replace all electrical tape joints, as well as any using household twist-on connectors—both eventually fall off, leaving exposed wires. Knife switches should also be replaced (due to the possibility of arcing), and panels should be installed with covers to prevent exposed terminals from accidentally shorting (a common problem when the rear of the panel is open and located in a storage locker).

Keep an eye out for loose, hanging wiring runs, damaged conductors and chafe, especially where wires pass through a bulkhead; these should be protected by rubber grommets. As for AC outlets, keep in mind that ABYC recommends that outlets in the galley, head, machinery spaces and on all weather decks be GFCI (ground fault circuit interrupter) types. If you don’t already have them, this is also a good time to think about installing an AC polarity-warning indicator, as well as voltage and amperage meters, since any motors in the system can be damaged by low voltage.

Engine Compartment Ventilation

A common problem here is the coiled ventilation ducting, another item that’s probably original to your boat because it rarely gets replaced, even if it’s split in so many places it looks like a Slinky. Inspect it thoroughly for kinks, crushed spots, splits and deterioration. Make sure the intake hose is properly secured and that it reaches the lower one-third of the compartment without going below the normal accumulation of bilge water.

Boats built after August 1, 1980 must have a powered ventilation system (a blower) for compartments with permanently installed gasoline engines and remote starters. Check the blower for corrosion and loose mountings, as well as the condition of all connections and wiring. The blower itself should be spark-proof (ignition protected) and labeled as such.

Freshwater Tanks and Hoses

Here’s a system that would probably get a lot more attention if sailors were relegated to drinking only water. It’s another place to look for components as old as the boat itself, and while I can’t recall any sinkings or fatalities attributed to nasty tasting water, anything that contributes to the crew’s health and overall well-being is worth a look. Start by tracing out the entire system, noting leaks, cracked fittings and loose connections. Inspect all hoses for kinks and chafing, and look for double hose clamps. If your boat has plastic hose, the best is clear, reinforced “food-grade” type, discernable by its slight mauve tinge. The worst thing I’ve seen was plain old garden hose, which not only becomes brittle over time, but also makes your water taste like mulch.

This is also a good time to open the tanks and take a look inside. Clear hose allows for easy examination, but you have to open an inspection port or two to find out what’s going on in the tank. If your fiberglass boat has built-in tanks, keep an eye out for any hull blistering while peering inside; osmotic blistering can occur due to water absorbed from inside the hull as well as outside.

Although this list of commonly neglected items onboard is by no means all-encompassing, you get the general idea. Despite salesman or manufacturer claims to the contrary, very few items on your vessel are truly maintenance free, and it’s up to you, the boatowner, to ferret out those potential problems napping aboard. Just remember, on a boat all dogs eventually wake up.

Frank Lanier is a marine electronics technician and owner of Capt. F.K. Lanier & Associates, Marine Surveyors and Consultants, in Chesapeake, Va.