Power Boat Trim for the Beginner

By Andrew Spaulding

The first time I jumped in the family Whaler without parental supervision, I punched the throttle forward just as soon as I left the dock and the bow shot up in the air blocking my vision. This was my first experience with bad trim in a powerboat and it wasn't much fun. Most boats have a way to adjust the trim of the boat through the outboard, sterndrive, or trim tabs. Trimming the boat properly is a way the driver can deliver the safest, smoothest ride for the conditions.

Many beginners drive powerboats around with their bows in the air, because they are unaware how the trim function can change the operation of the boat. This is understandable since there isn't really any equivalent in cars or motorcycles. However, a properly trimmed boat is easier and safer to drive for many reasons.

There are a few key points to trimming a boat properly. Once you understand these and get a little practice, you’ll be driving like a pro in no time. A boat needs to be balanced in two directions – fore-and-aft and side-to-side. A smaller boat without trim tabs needs to move people and stuff side-to-side to get that balance proper. Larger boats with trim tabs can use them to straighten side-to-side trim as well as fore-and-aft. Take care to not use too much trim tab to straighten the boat. Using more trim tab than necessary causes more drag on the boat, slowing the boat and wasting fuel.

Fore-and-aft trim is adjusted on smaller boats with the stern drive angle or outboard angle. Typically, the switch controlling this is on the side of the throttle control. The proper fore-and-aft trim for any size boat will change with the conditions. For popping skiers out or “hole shots”, trim the bow down. This will minimize the cavitation (when the prop breaks loose from the water) and keep the bow down for better visibility.

Generally speaking, as the boat comes up on a plane, you will want to trim up the bow for a smoother ride. If the bow is too low in the water it can catch a wave pushing the boat around making it difficult to steer. However, in rough weather you want to do the opposite. You will want the bow down so that the waves are sliced by the sharp part of the bow, not slamming into the flatter part of the boat bottom behind the bow. In very windy conditions, if the bow is too high, wind can get under the boat causing a dangerous loss of control. When you are pulling a skier or tuber, you should keep the bow trimmed lower. This will help keep the boat from losing speed in sharp turns.

As you are learning to trim a boat properly, make small adjustments to the trim so that you get a feel for how much trim is necessary to make a difference. Since all boats react differently to different trim levels and conditions, practice doing maneuvers at different trim levels while you slowly increase your boat speed and repeat them as necessary to get a feel for the boat. It is easy to get a boat out of control with too much speed and poor trim, so please be careful out on the water.

Bodacious Dream Wins Leg Two of the 2013 Atlantic Cup

If this looks familiar, it is - changes in bold. Bodacious Dream wins leg two of the 2013 Atlantic Cup. Chicago sailors Dave Rearick and Matt Scharl cross the finish line 4 minutes and 59 seconds ahead of the second place boat after 231 nautical miles. Check out the event site by clicking here for more  photos and video. Check our blog here for a larger picture. Photo credit Billy Black.

Memorial Day 2013

Memorial Day is coming up this weekend. While you are out on the lake enjoying boating or munching a burger at a backyard BBQ or enjoying a parade, it is important to remember why we have the holiday.  Memorial Day is the day that we remember the sacrifice of the over 1 million men and women who gave their lives in the service of their country.  

The holiday started after the Civil War to honor the Union and Confederate soldiers that died during the war. By the opening of the 20^th century, the honors were extended to all who have died in military service. Traditionally, on Memorial Day the flag flies at half-mast to commemorate the dead until noon when it is raised to full hoist to remind the living we need to ensure their sacrifice wasn’t in vain.

While Veterans Day is for all veterans and Memorial Day is for those that have died in uniform, I think it is important to give thanks to all veterans and military families on Memorial Day. At Crowley’s Yacht Yard we are honored to work with five veterans that served overseas during times of armed conflict:

Dick Gravengood – World War II

Bill Savage – Vietnam

Matt Markiewicz – Gulf War I

Andrew Spaulding – Gulf War I

Ritchie Geoghan – Gulf War I

Bodacious Dream First to Finish Leg 1 of the 2013 Atlantic Cup

Bodacious Dream wins leg one of the 2013 Atlantic Cup. Chicago sailors Dave Rearick and Matt Scharl cross the finish line 8 minutes and 28 seconds ahead of the second place boat after 642 nautical miles. Check out the event site by clicking here for more  photos and video.

Marine Corrosion - Part 2

By Andrew Spaulding

Last week in “Marine Corrosion – Part 1” we discussed some marine corrosion terms and how sacrificial anodes work to protect your boat’s underwater metals. This week, I want to cover the corrosion survey process. The goal of a corrosion survey is to measure the potential of the individual underwater metal units and the boat as a whole without any outside influence with a reference cell. A reference cell can be one of several types, the most common being silver/silver chloride or zinc. The metal that makes up these reference cells is pure or a very specific alloy. The potentials between these reference cells and many different metals and alloys have been recorded in tables by laboratories.

Once these measurements are recorded for the boat in question, the values are compared to the reference cell tables. The potential between a fiberglass-hulled boat and a silver/silver chloride reference cell should be from -550mV to -1100mV. If the boat as a whole is in this range, you boat has the proper amount of sacrificial anode.  If your boat is less negative than this, you are under protected against galvanic corrosion. If your boat is more negative than this, you are over protected.

You may think that over protected is ok, but unfortunately, being over protected has its own set of problems. Under water coatings can be literarily blown off the bottom by gas bubbles forming on the surface of the metal. Also, an alkali solution can form on aluminum which will eat into the metal.  Neither of these issues are good and their symptoms can look like galvanic corrosion. The reason we use precise alloys for our reference cell and a volt meter that is accurate measuring 10s of millivolts is so that we can know what is going on with the boat, not make guesses, nor assume that the dock chat about corrosion is correct.

Once we have the boat’s hull potential recorded and the underwater metals are surveyed, the corrosion survey can progress. While measuring the hull potential, we turn on and off every direct current circuit. If the boat has a problem, one or more of the circuits will change the measured hull potential. This is an indication that that circuit has a fault that needs to be addressed.

If the boat lives at the dock plugged into shore power, this process needs to be repeated with the AC power cord and all of the AC circuits. Typically, AC power is not a contributor to long term corrosion issues, but since some AC circuits are intermittently used it is important to test them as part of a corrosion survey. AC power can be the source of serious corrosion, although it is usually so severe that it gets noticed quickly.

Corrosion due to a faulty electrical circuit is called stray current corrosion. Stray current corrosion severely damage underwater metals in a very short period of time. The pictures above show a propeller and shaft that were damaged to the point of replacement in a few weeks.

Last week, I went out to start a corrosion survey. We didn’t get a chance to finish the survey due to thunderstorms, but we did find some suspect DC circuits. We also measured the hull potential at the maximum for galvanic corrosion protection. Any more protection and the boat would be over protected. This condition is okay at the beginning of the season since the anodes are at their maximum potential. I would expect as the anodes do their work over the season, the hull potential of the boat will settle into the middle of the acceptable range.

Departing Crowley's Yacht Yard

Departing Crowley's Yacht Yard for one of Chicago's harbors. Photo thanks to Jon Paige, Rigging Manager, Crowley's Yacht Yard

Marine Corrosion - Part 1

By Andrew Spaulding

Marine corrosion is an insidious force that chews away at our underwater metals. At the start of any corrosion conversation, I think it is important to review terminology. Often the terms used have specific meanings that are muddled in common use, or we use portions of a term leaving the discussion open to interpretation. In an attempt to avoid both of these situations, we’ll start today’s marine corrosion discussion by reviewing some terms.

 Often you will hear the term “electrolysis” used to describe the effects of corrosion, but strictly speaking electrolysis occurs when DC current drives a chemical reaction. So electrolysis could be the cause of your corrosion, but it isn’t the correct term to use for galvanic corrosion or crevice corrosion or AC stray current corrosion - all of which could be the cause of underwater marine corrosion.

Ground is another term that is used improperly. You don’t have a ‘ground’ on your boat. However, you may have up to 5 ‘grounding’ systems onboard. There is a DC negative ground system that acts as a return path for DC current. If you have an AC (alternating current, not air conditioning) panel, you have an AC safety ground system that prevents AC electrocution. You have a bonding system connecting the underwater metals electrically for corrosion protection. You may have a RF/SSB ground plate for counterpoise. And lastly, you may have a lightening ground system for strike protection. All of these systems have a “ground” function, but they are designed to be separate, discreet systems.

Another marine corrosion term that gets misused is “zinc”. Zinc is a type of anode material that is commonly used in sacrificial anodes onboard boats. Anodes can be made of zinc, magnesium, or aluminum. For fiberglass boats in fresh water you should be using magnesium anodes. Zinc anodes don’t have enough potential to protect the underwater metals very well, if at all.

Graphic thanks to Electro-Guard, Inc. (http://www.boatcorrosion.com)

Sacrificial anodes protect under water metals with their galvanic potential. Any two metals that are electrically connected (with a wire or physically in contact) to each other and in an electrolyte generate an electrical potential that is measurable.  If the two metals are lead and copper for example, and the electrolyte is salt water the potential generated is about 100 millivolts.

Properly-sized sacrificial anodes will push the galvanic potential of the boat’s other underwater metals negative by about 200 millivolts. This is enough change in potential to ensure that the anode is sacrificed in place of the other metals. Since fresh water isn’t a great electrolyte, magnesium anodes provide the extra negative potential that is necessary to protect the other underwater metals. Aluminum-hulled boats and certain stern/sail drive applications require the use of aluminum anodes. Wood-hulled boats have different concerns all together – it is critical to not OVER protect the underwater metals in a wood boat or damage to the wood can occur.

The bonding system provides the electrical connection to connect all of the underwater metals into one big galvanic system.  Since we know what the galvanic potentials are for all of the underwater metals, we can measure them with a voltmeter. As we add anode material to the galvanic system we can see changes in the voltmeter. Also, if a piece of equipment onboard is leaking current into its ground system, we will see changes in the voltmeter reading as that equipment is turned on and off. It is through this process that we find what is causing marine corrosion to occur.

Later this week, I am headed to the harbors to conduct a corrosion survey for a boat. I will have the results to report in next week’s newsletter: Marine Corrosion Part 2. Hopefully, I will also have the answer to solve this boat’s annual battle with corrosion.

The World Television Premier of Chicago Drawbridges

http://www.chicagodrawbridges.com/

THE WORLD TELEVISION PREMIER OF

Chicago Drawbridges

will be broadcast on WYCC -Channel 20! 

May 5 @ 8 p.m.

May 6 @ 9 p.m.

Chicago Drawbridges is a documentary directed by Stephen Hatch and narrated by Patrick McBriarty, author and bridge historian, chronicling the importance of the bridges in the making of the Windy City, from the very first wood footbridge, built by a tavern owner in 1832, to today’s iconic structures spanning the Chicago River. 

Informative and entertaining this 56-minute film tells the story of Chicago’s development through the bridges based on the forthcoming book Chicago River Bridges from the University of Illinois Press (October 2013).

Created and produced by Stephen Hatch and Patrick McBriarty it also interviews professor, geographer, and author David M. Solzman, PhD.; Brian Steele, Director of Communications for CDOT (2001-2011); map maker and historian Dennis McClendon of Chicago CartoGraphics; James S. Phillips, PE (ret.); Ozana Balan King, Museum Director, McCormick Bridgehouse & Chicago River Museum; Grant Crowley owner of Crowley's Yacht Yard; Betsy Steinberg, Managing Director of the Illinois Film Office; CDOT Engineer Vasile M. Jurca, P.E.; and Professor Michael Latham from Roosevelt University.  

More Boats Ready for the Harbors Everyday

Thanks to a great crew at Crowley's Yacht Yard for getting more boats in everyday ready for the harbor.

Hazards to Navigation: Fog

By Andrew Spaulding

With 80 degree temperatures and boats going over the wall at a furious pace, you’d think that spring time is over and we are well on our way to summer. However, current conditions are perfect for fog formations in the afternoons and evenings. So venture out prepared and take the initiative to leave Crowley’s dock a bit early to make it to the harbor before the evening fog comes up.

What is fog? There are many types of fog, but for the most part they are very similar. Technically, fog is a type of stratus cloud that stays very close to or on the ground. Fog begins to form when water vapor condenses into tiny water droplets in the air and normally occurs at a relative humidity near 100%. This is achieved by either adding moisture to the air or dropping the ambient air temperature.

Advection fog occurs when moist air passes over a cool surface and is cooled which is what happens here in Chicago before the lake warms up. When the sun goes down the warm, humid air is no longer being warmed, and the cool air off the lake chills the air, causing the water vapor in it to condense into water droplets. Wham-O, we’ve got fog. The tough part about this is it coincides with the sun going down which can make for an interesting trip back to the harbor.

What to do? Be prepared. If you’re going to be out after sunset be ready for fog, particularly if the wind is light or out of the east. On the way out, make sure that your navigation electronics are working and you have compass headings and distances written down so that you can “dead reckon” if necessary.

Once the fog rolls in, proceed at a cautious speed making the appropriate sound signals for your vessel. A power boat underway is required to make one prolonged blast (4-6 seconds) of their fog horn every two minutes. A power boat stopped on the water is required to make two prolonged blasts (not more than 2 seconds between them). Most other vessels including ones with restricted maneuvering, fishing, sailing, towing or pushing are required to make three blasts in succession: one prolonged blast followed by two short blasts. Also, don’t navigate directly from buoy to buoy. Lots of people do this and it can lead to a pile up (literally) at the buoy. Instead, navigate a bit away from the buoy you are aiming for, on the correct side of course.

Thanks to Mike Hamernik and the Chicago Weather Center Blog (click here to view) for the article idea.