Ask The Experts

Solutions from the BoatUS Tech Team

Breaking Bad

We have a 1993 Chris-Craft that eats alternator belts. Late last summer, the alternator belt broke. We replaced it and that one broke also. Since then, we have had a new alternator and several belts replaced only to have the belt break once again. The alignment has been checked by two marine mechanics both times. They have tried without success to find out why the alternator belt keeps breaking. This latest one lasted a week before breaking. What else should we look for that would cause the belts to break?

Don Casey: There are several possibilities. The most common cause of premature belt failure on a boat is rust. All of your pulleys need to be rust-free and as smooth as silk inside the V. Just one little lump of rust will tear at the belt several thousand times a minute. Remove the belt and inspect every pulley it runs over, using the tips of your fingers to feel for roughness. If you find any, remove it by wet-sanding. It is a good idea to protect a rehabilitated pulley with paint. While you have the belt off, check the bearings of all the components this belt drives. It might be that you have a failing bearing in your water pump. Turn all pulleys by hand, feeling for any roughness or drag. Replace anything suspect. Your new alternator does not get a pass here, particularly if it is a rebuilt unit.

Also check the alignment yourself. It doesn't take much misalignment to cause a belt to heat up and wear. A length of arrow-straight dowel dropped into the empty pulley slots is good for revealing alignment problems. You will need to recheck alignment after you install and tension the belt. Here a straight edge on the face of the pulleys should expose tension-induced skew.

Finally, suspect the belt. The proper belt sits slightly above the pulley sides on all of the pulleys. If the new belt sits lower, it is too small. Not all belts are created equal. I have personally experienced belts purchased from national auto supply chains that died in hours just from poor construction. Gates Green Stripe belts enjoy a sound reputation. The right belt won't need to be over-tightened, another common cause of failure. Tighten only enough so that turning the alternator pulley by hand rotates the crankshaft pulley.

How big is big enough?

I have a Shannon 37 ketch, and my goal is to go cruising. The boat has a 45-pound CQR. I need to upgrade to a newer-style anchor. I'm looking at spades and Manson Rays because of the bowsprit side-mounted roller, which would interfere with the roll bars on the Rocnas and Manson Supremes. Beth, I've read your book and noticed you had a 44-pound Bruce on Silk. Was it sufficient, or would you have fared better with 55 pounds?

Beth Leonard: Choosing the proper anchor size means balancing the holding power of the anchor against the weight-carrying ability of the boat. Sitting out all sorts of weather in a wide variety of anchorages over the years has made me a believer in carrying a storm-sized primary anchor on the bow, so when those first gusts from an unforecasted gale start, you can roll over and go back to sleep. But there is a limit. On a fine-bowed boat, especially one with a long bowsprit like the Shannon, sailing performance will suffer if you size the anchor too large.

For a boat that can carry the extra weight on the bow with a bow roller that can accommodate it, go up one size from the manufacturer's recommendation if you intend to do more than weekend sailing. But where the boat is sensitive to weight in her ends, the tradeoff is more difficult. In your case, I can tell you that we never dragged with the 44-pound Bruce, so the extra weight would not have made us any safer but would have affected boat performance. Exchanging your 45-pound CQR for a more modern design will increase the holding power for the same weight, and be equivalent to going up one anchor size. For a 37-foot boat, Spade recommends a 33-pound anchor and Manson recommends a 44-pound Ray (a claw anchor very similar to the Bruce). Given that the Shannon can carry 45 pounds without seriously compromising sailing performance, I'd go with the 44-pound version of either of these. Both will perform well in almost any conditions and better than your CQR on many bottoms.

Binding Matter

I have a 1988 Sea Ray 270, with sterndrives. When I shift from forward to reverse or vice versa, the shifting is very stiff. This is a problem when I am docking the boat. Can I lubricate the shift cables, or is there something else I can do to loosen them up?

John Adey: If the cables are original, then it is probably time to replace them — an inexpensive fix and will be a significant improvement! The cables are sold by length and specific to the engine manufacturer when it comes to the ends. You'll get a generic cable, then a package of ends for Mercruiser applications. You can try some WD-40 in each end of the cable; if this works, it's probably only a temporary fix until the lubricant dries out.

Prehistoric Gas

My 25-foot Sea Ray has been sitting next to my home with 100 gallons of gas for three years. What fuel additive can I add to bring it up to par?

Tom Neale: This is a common concern, particularly after winter storage. Your issue is worse because of the time involved. Unfortunately, most people familiar with this will tell you that there isn't any product upon which you can really rely to bring that fuel up to par after three years. With the price of fuel today, I cringe at saying this, but the safest thing to do is to get a qualified professional to remove the fuel, dispose of it, and fill up again, using a good additive. I say "qualified professional" because there's always a risk of explosion and fire when you're doing a job like this, and the fuel will have to be stored safely and then disposed of legally. As expensive as this advice is, the flip side is that if you take the chance and add some product hoping that it'll restore your fuel, you could end up with some very hefty engine repair bills — far more than the cost of getting rid of the old fuel and buying more.

If the fuel has ethanol in it (highly likely in California), you should also take the opportunity, while the tank is empty, to have the same professional check and clean the tank. It's money well-invested.

Standards vs. Regulations

I own a 2004 Aquasport with twin outboards and want to know about the fuel/water separator bowl mounted on the fuel filters. I read that the USCG requires the metal bowl on enclosed engine compartments (fire resistance), while on outboards the plastic clear bowl is allowed. My fuel filters are mounted in the aft bilge compartment on the transom. Could I use the much more practical clear bowl, or do I still need the metal ones because the filter is in the bilge compartment?

John Adey: The answer in your case is based on the difference between federal regulations and standards; you have an outboard-powered boat and therefore you are not subjected to the fuel regulations. From an ABYC standards standpoint, you can use a clear bowl because the location is not inside a "gasoline engine space" (as per ABYC H-24 Permanently Installed Gasoline Fuel Systems, If you had, let's say, a generator in that space, then you need a unit that passes the "fire test" (a metal bowl is generally used to meet this requirement). There are manufacturers that have a clear bowl with a metal shield that allows you to still see the fuel in the filter and determine if it's dirty or has water in it. The good news is that if a builder advertises that he follows the ABYC standards, then he also complies with the federal regulations plus much, much more!

Of-Season Oil

Your BoatTECH files ( recommend changing engine oil twice a year if the boat is seasonal. Wouldn't it make sense to just drain it when you quit using it, and then refill it when you start using it?

Don Casey: No. If you are trying to save the cost of an additional oil change (or if you have environmental concerns about unnecessary oil "consumption"), fill the engine with your fresh oil at decommissioning. It will store nearly as well there as in a jug, but inside the engine it also protects the oil pump and other components in the sump not designed for air exposure, and it eliminates the "exposure" of forgetting that there is no oil in the engine at recommissioning. If you just do one oil change annually, do it at decommissioning to remove the acids that will otherwise attack bearing surfaces while the engine is idle.

Dual oil changes are a bigger imperative for diesel engines, but all engines benefit from clean oil. In the fall, I run the engine before the oil change to put contaminants in suspension in the oil so that most are removed with draining. However, I also run the engine for several minutes after the oil change to displace old oil with fresh, on all the interior surfaces of the engine. This dilutes any acids the old oil was harboring, reducing the potential for damage to precision surfaces. I tend to run the engine on this oil change for a few hours when I recommission, viewing it as a kind of annual flush. Then I do my new-season oil change, happy in the knowledge that I am giving the interior components of my expensive engine the best possible care.

Early Warning

My exhaust bellows has a hole in it. Can I get the rest of the season out of it without harming anything? The other two bellows look good. I plan on changing all three at the end of the year. This is on an Alpha One sterndrive.

Don Casey: Probably. The exhaust bellows doesn't keep out the ocean. It just corrals the exhaust. Unless the hole is badly located where it heats or sprays something sensitive, it should not hurt anything. However, the exhaust bellows is a bit like the canary in the coal mine. When it fails, the drive bellows will not be far behind. Your plan to change them all in the off-season is a prudent one.

Shore Power

I have a small cruiser on a lift at a marina. Should I be leaving the shore power hooked up at all times? There are two batteries, a Perko switch (turned to the 'Off' position while at the marina), and a charger.

Tom Neale: My preference would be to leave the boat plugged in, if you can safely do so, with the AC shore power to the charger (but turned off everywhere else) so that your batteries can be properly maintained, provided marina rules allow this.

Photo: Jet DockBoats stored out of the water benefit from being left on a charger, if it has a "float" stage that won't overcharge the batteries. (Photo: Jet Dock)

You didn't mention your type of charger. To do this, you should have a marine-grade charger typically referred to as a "smart" charger. These chargers are configurable to your type and size of batteries and will charge according to the battery needs. Most have three stages: a bulk stage for when you begin to charge low batteries, an interim stage, and a float or maintenance stage that will keep the batteries topped up but won't overcharge them. Your batteries should be of the same type (such as, for example, wetted lead acid, gel cell, or AGM). A charger that doesn't do this can ruin your batteries and could possibly cause a fire if left on unattended. There are even chargers today that can be set to charge different types of batteries.

Pumped Up

Can I use a Jabsco (or any other brand) impeller in place of an Oberdorfer impeller in my 1969 Atomic Four engine? I ask this because an Oberdorfer impeller will cost $48, which seems high.

Tom Neale: Yes, you probably can. There are usually impellers made by various manufacturers to fit pumps. But you didn't say which Oberdorfer pump is on your Atomic 4. Many times an engine manufacturer may use one or more pumps from the same or different pump manufacturers over the years of production. Sometimes a repair yard will have switched out a pump, although this is unlikely. You should ask the manufacturer of your choice (and Jabsco is a good start) if it has an impeller for your specific pump. But none of them are cheap, and an impeller that's unusually cheap may indicate a product of lower quality, which you don't want. If you lose a blade or part of a blade, it can cause blockage in your cooling passages. However, that price, in my view, is very high for that impeller absent unusual circumstances.

You can also Google "Jabsco impeller cross reference" or "Oberdorfer impeller cross reference" and get many results. Get your pump part number and you'll probably find several choices. A good parts supply shop can cross-reference numbers for you. If you don't know which Oberdorfer pump you have, you may need to remove it to get a number, or take it in. You should remove and rebuild these periodically, anyway.

More Power!

When using a splitter going from a 50-amp, 250-volt feed down to two 30-amp cables, is each 30-amp cable receiving 25 amps? If I put the inside boat breaker on the parallel, how much is each side receiving, 25 each or are they sharing the 50 amps as needed by both 30s? Second question: Using a pigtail going from shore power 50 amp/250 volt to a single 30 amp, how many amps is the 30 getting, 25 or 50? I'm asking these questions because my power pedestal has two 50/250s that I can plug into. Right now I'm using only one with a splitter. When the compressor for the two HVACs, the fridge, and the hot water heater all happen to kick in at the same time, it throws one of my 30A breakers inside the boat. I need to know if using the second 50/250 with the pigtail will eliminate the problem by supplying the needed amps.

John Adey: Fifty amps will generally run around 55-60 amps before the breaker trips. And no, your splitter does not equally distribute the power; it goes where the draw is. So, the best solution to your problem, as I understand your question, is to use two separate 50/30-amp adapters with your two cords. This assumes three things:1. with two 30-amp services there is no 220 onboard
2. the two inlets each power separate panels (unless paralleled), possibly one for an HVAC unit, and the other for the house panel. 3. when the two 30-amp cords are connected, inlet A is not connected to inlet B Your boat will never draw more than 35 or so amps on each cord so there is no worry connecting to a 50-amp outlet with a 30-amp cord. The two separate cords should solve your problem. 

— Published: December 2012

Winter Battery Storage

When wet-cell batteries are allowed to discharge, the electrolyte becomes pure water, which will freeze and ruin the battery. If you can, take the battery off your boat and store it somewhere dry and cool (but not freezing). You may have heard that a battery will discharge if left on a concrete floor, but modern batteries make this precaution unnecessary.

Wash and thoroughly dry the top of the battery to reduce the potential for self-discharge. Don't leave stored batteries connected to a portable charger. Unless the charger turns off completely — few do — the batteries will suffer damage. However, stored batteries should be brought to full charge once a month, so post a reminder for yourself. If the batteries will be stored aboard because they're too heavy for convenient removal, they must be maintained in a full-charge condition all winter. This requires a charger with a "float" stage and power connection. In lieu of an unattended power connection, a solar panel might be employed to counter self-discharge. Find more winterizing tips and battery hints at


Meet the Experts

Photo of Don Casey

Don Casey
He's been one of the most consulted experts on boat care and upgrades for 30 years, and a panelist on our "Ask The Experts" website for a decade. He and his wife cruise aboard their 30-footer part of the year in the eastern Caribbean. His books include Don Casey's Complete Illustrated Sailboat Maintenance Manual, and the recently updated This Old Boat, the bible for do-it-yourself boaters.

Photo of John Adey

John Adey
The president of the American Boat & Yacht Council (ABYC), John grew up boating. He's been in the industry since 1990, with experience from a yacht brokerage and boatyard to owning a marine supply store. He and his family sail their classic 1976 Irwin ketch, a boat he completely restored. John is a trusted source for technical information for industry professionals.

Photo of Tom Neale

Tom Neale
He's maintained, lived aboard, and cruised long distance on boats with his wife and family for most of his adult life. He can take apart and fix almost every system aboard a boat, has written two books, filmed a two-set DVD on East Coast cruising, written for top marine magazines, and has won seven first-place awards from Boating Writers International and many awards for his technical writing.

Photo of Bob Adriance

Bob Adriance
The editor of Seaworthy, the damage avoidance newsletter of BoatUS Marine Insurance, Bob has written hundreds of articles on safety, loss prevention and causes of boating accidents. His 2006 book, Seaworthy, Essential Lessons of Things Gone Wrong, is based on 20 years of real claims files. He's owned Folkboats to J-Boats and currently sails a 36-foot sloop.

Photo of Beth Leonard

Beth Leonard
BoatUS Magazine's new technical editor, Beth Leonard, grew up powerboating, waterskiing, and fishing on Lake Ontario. Since 1992, she and her husband have completed two circumnavigations on two sailboats, doing all maintenance themselves. They also installed the systems on their 47-foot aluminum sloop. Beth has written The Voyager's Handbook, the how-to bible for offshore sailors, and hundreds of technical articles.


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