Hull Fittings

     Just a short post tonight, concerning thru-hull fittings. Sea Ray used plastic fittings when my boat was built. The danger here is that these fittings weaken and embrittle over time, and can crack or break off completely at the hose nipple. Imagine if that happened to a bilge pump discharge line - now the bilge can't empty, and there is a hole into the boat near the water line. Failures like this have sunk many boats - mine won't be one of them.
     An old friend (not that he's old; I've just known him a long time..... does that mean we are both old?) came up to help me with this job recently, and it went quite smoothly. We removed all 5 of the plastic engine room fittings, and replaced them with stainless steel.

      I will upgrade the remaining fittings on the boat as time permits. These were the most important to do, before the new engines go in. All in all, an easy upgrade, and not too expensive. The peace of mind? Priceless.....

More Generator Details

     The cooling system is critical to the life and proper operation of the generator. The system is divided into two subsystems - the raw water cooling side, and the closed cooling side. The raw water system is comprised of the thru-hull fitting, seacock, strainer, raw water pump, heat exchanger, and exhaust system. The closed cooling portion is similar to the cooling system of a car, with recirculated coolant, a circulator pump, associated hoses, and the closed cooling side of the heat exchanger. In operation, the coolant carries away the excess heat of combustion, and passes it to the raw water via the heat exchanger. The heated raw water is discharged with the exhaust, which it also cools. Simple enough on the surface, but again, the devil is in the details.
     As I mentioned in the previous post, a siphoning condition can be created, if the generator is below the water line, wherein raw water can bypass the raw water pump impeller, and flood the exhaust system, as well as the generator itself. The resulting engine damage is not covered by the generator warranty. After all, they do describe the proper install techniques in an installation manual - available on the Westerbeke website. It is a good read whether or not you are actually doing an install, and provides a great deal of useful information for marine generator owners. Since I covered the vented loop installation in the last post, I won't get into it again. Just make sure yours is operating properly.
     On the raw water side, I installed all new hoses, and double clamped every joint, with two exceptions. The raw water pump on the generator has a specialty nipple for the hose connection, and it only has room for one clamp. As it operates under negative pressure, I am not overly concerned, but I will keep an eye on it. The Groco vented loop also will not support double clamps, but these hoses are all above the water line in my boat, so again, I am fine with it.
     The muffler isolation mounting was previously discussed, but I should mention that the generator to muffler connection on a 340 like mine is a bit tight. Conventional rubber exhaust hose is a bit stiff, so I used corrugated, wire reinforced blue silicone exhaust hose for this connection. It is expensive, but the enhanced flexibility and longevity makes it worthwhile. You can see a portion of it here:

     It is important to route this hose with a constant downward pitch. Do not create any low spots that can trap water between the generator and muffler. Under rough conditions, that water could slosh back up into the generator, and damage it.
In the picture above, you can also see a yellow-handled ball valve and hose nipple. I made the aluminum block in my milling machine, and threaded the fitting and valve into it, then mounted the assembly next to the generator, to make the oil changes easier. The original Westerbeke setup is simply a hose with an NPT pipe cap on the end, held in a bracket right behind the raw water pump impeller. It is hard to access, blocks the access to the impeller, and would probably result in an oil spill every time the generator needed an oil change. With this modification, all I have to do is connect the hose from my vacuum oil changer to the nipple, open the valve, and all the engine oil is sucked out. The valve has a locking hasp on the handle, so it can't open accidentally. And now, it is much easier to service the raw water pump.
     Last, but not least, are some electrical details. As you know from some older posts, the 4 engine and house batteries were moved out of the engine compartment. The generator battery was not. I placed it just forward of the generator, on a custom machined aluminum battery tray:

     I modified the battery tray to accept a heat shield, which you can see to the right of the battery. This protects the battery from any radiant heat from the generator, and also acts as a convenient mounting point for the wiring and fuel line. Speaking of wiring, you can see two wires that connect to the positive battery post - one for the generator itself (the large red one to the right), and the other for the battery to charger connection. There is a fuse holder in this lead. ABYC recommendations stipulate that a fuse be placed within 7 inches of battery positive terminal connections, with the exception of larger starter cables. The fuse holder meets this requirement. I placed red shrink bands around the wire to indicate its positive conductor status.
    One more thing - the generator fuel system. As you can see, I used metal braid over Teflon line (Goodridge #811 hose) for the fuel system. I will be using this same fuel line on the engines. There is an excellent article written about modern fuel line here:
http://www.hotrod.com/techarticles/engine/hrdp_1101_performance_fuel_hoses/index.html

Take the time to read it - there is a lot of information here concerning rubber fuel hoses, ethanol fuel, and the resulting reactions. The hose I am using is made from Teflon tubing, and is 100% resistant to Gasoline, Ethanol, Methanol, and even Nitromethane. It is 100% resistant to vapor permeation, lightweight, flexible, abrasion resistant, and never needs replacing. It also exceeds all marine standards for fuel hose. There is, of course, a drawback, and that is price. it runs about $10.00 to $12.00 a foot, and the hose ends aren't cheap either. But if you want it done once, and only once, it's the way to go.
     And with that statement comes a warning. Metal braided fuel line forms an electrical connection between the engine/generator and the boat's fuel tanks. If, by chance, the engine's ground cable were to be somehow compromised, and the starter engaged, the braided fuel line becomes the engine ground conductor. The result can be a melted fuel line and potential fire or explosion. If you use metal braided line, there MUST be a break in the circuit between that line and the boats ground. I accomplished this by using a short section of hose, between the fuel tank and the fuel filter, that has a Kevlar braid instead of the metal braid. The engines will be similarly isolated. OK, I'll get off the soapbox now....

Generator Details

     I have been working for a week or two on the generator, and I am happy to say it is done - installed and running. Here is the finished install:

     I have to say, this is not a job you should attempt without a thorough understanding of marine electrical, cooling, and exhaust systems. There's more than one way to damage the boat, or harm yourself, due to an improper install. I am going to go over a few of the major points here, but this is by no means a complete treatise on a job such as this.

     First, the generator can be damaged badly by water reversion, and this is NOT covered by the warranty. There is a connection that must be made between the raw water discharge from the engine mounted heat exchanger, to the exhaust elbow. It is critical that, if the generator is near or below the waterline, that a vented loop be installed at the highest possible point in the engine room, to prevent siphoning when the generator is not running. This is a serious requirement - an improper installation here can destroy the generator. Sea Ray used a cheap plastic vented loop in the original install, and the one I got with the boat was partially melted. I replaced it with a bronze loop from Groco:

     I mounted the vented loop on a custom made billet aluminum bracket, along with some machined plastic spacers. Then I bolted the bracket in place, just under the hatch, as shown. This vented loop can be serviced by simply unscrewing the top, and cleaning or replacing it.

     In the next post, I will discuss the cooling and exhaust systems, and maybe the electrical system too.

Generator Install

     Last weekend, my brother was kind enough to come out and help me install the new Westerbeke generator. Gas powered 2002 Sea Ray 340s originally came with 4.5 kW generators, but these are no longer made by Westerbeke. The current version is a 5.0 kW, available in either a standard carbureted or Low CO, fuel injected version. I had intended to install the Low CO version, but it is almost 5 inches wider than the standard model, and would make maintenance too difficult. In fact, it may not fit at all in this boat, without interfering with the starboard engine exhaust manifold. So, the standard version it is.
     In order to perform the lift, I made up a sling from steel cable, to support an electric winch that was suspended from my backhoe bucket. I rigged it this way to provide for precise control of the placement, since the backhoe is really more suited to gross movements, not fine control. With this setup, I could lift the winch/generator assembly over the transom, shut down the backhoe, and then use the winch for final placement. The rig is easy to see in the pics:

     So, it is in, nice and smooth. I will detail the finer points of the installation in upcoming posts...

Generator Exhaust

     One of my goals with this boat is to enhance comfort through noise reduction. One way to do this is through acoustical isolation, and that is the subject of today's post. Those of you following along have probably noted that I mounted the A/C circulating pump on silicone foam pads, with great success (see the December 11, 2010 post). Continuing that methodology, I am mounting the generator muffler on isolation pads as well.
     The first step is to open up the 4 mounting holes on the muffler base, to approximately 1/2". Next, I fit rubber grommets into the holes. These are sized with a 1/4" central hole, which allows the 1/4" mounting screws to fit through easily. The purpose of the grommets is to isolate the muffler from the mounting screws in the horizontal plane, so that no vibration is transmitted from the muffler to the screws, and then to the hull.
     Next, my wife cut out some some mounting pads, using 1/4" thick closed cell silicone foam. These pads are trimmed to fit the corners of the muffler base, and are almost invisible once the muffler is placed on top of them. We used a 1/4" hole punch to make holes in the pads for the screws to pass through.
     Finally, we made some circular foam pads that are slightly larger than the stainless steel flat washers that are placed on top of the muffler base, and similarly punched a central mounting hole in these as well. These pads isolate the muffler in the vertical plane, with the result that the muffler is now in no direct contact with any rigid structure of the boat. The final installation looks like this:

     You can push the top of the muffler around about 3/8" of an inch in any direction, but it is still securely mounted to the boat, and is in no danger of coming loose. Lightly tapping on the muffler with a blunt object (I used my head) results in no vibration being transmitted to the hull. The final installation is shown in the following pictures. Note that all hose connections are double clamped, and that the discharge hose is installed with the highest possible arc, to prevent water reversion. As you can see, both the bilge discharge hoses, and the muffler discharge hose, are routed directly up and underneath the cockpit sole - the highest possible point. In both cases, I was able to increase the height of these hoses, as compared to the factory installation, by several inches.

     I will be detailing the generator installation soon, but in the meantime, here are a few more pictures of it, as it arrived:

Struts and Rudder Ports

     If you look at my post from February 6, 2011, there is a picture of the strut when I was pulling the cutlass bearings. As you can see, the surface of the strut is slightly pitted, and covered with barnacles and surface corrosion.The bedding compound is also in rough condition near the outer edges. So, my wife and I spent an afternoon scraping out the sloppily applied bedding compound from around the edges of both struts, and both rudder ports. I then ran an air line out to the boat, and used one of those small, residential sized sandblasters, along with a flexible sanding disc mounted on a grinder, to strip all four castings down to bare metal.

     I was very careful to thoroughly clean the area between the hull and the castings, to assure a proper bond for the 3M 5200 adhesive sealant, which was applied immediately after the sandblasting. I filled the entire void area around the castings, and fared the sealant smooth to minimize turbulence and drag. 5200 takes at least a week to cure, so I am leaving it alone for a while now, and moving on to other projects. My goal is to paint the struts and rudder ports while I am doing the barrier coating of the hull, but it will be a few weeks before I get to that. In the meantime, I am going to work inside the hull, on this new arrival...

     More to come...

Engine Mount Brackets

     I know, I know. It's been a while. Family, friends, commitments, responsibilities, work - doesn't leave much time for boat building, and even less for blog posting. But we'll catch up this week (it's worth the wait...).
     So, on to today's post. In many older boats, and, unfortunately, lower quality boats, the engine mounts are lag bolted to the stringers directly, with the lags running vertically down into the plywood core. This method works fine at first, until the stringer core absorbs enough water to begin to rot. The water entry is inevitable, since there is no way to seal the penetrations with 100% certainty, over time. And, unfortunately, a boat built with this method of construction probably was not sealed that well at other penetration points either, so the odds in favor of water intrusion are quite high.
      This is when the fun starts. Re-tightening the lag bolts won't work, and increasing their size is only a band-aid solution. Replacement of the stringers is the only proper solution. Depending on the age and value of the boat, this may or may not be a viable option.
     A far better method for anchoring the engine mounts is the "L" bracket / backing plate combination. In this arrangement, an "L" shaped bracket is bolted to the stringer with horizontal bolts, which sandwich the stringer between the bracket and a thick backing plate. This method helps prevent water intrusion, due to both the orientation of the bolts, and the tighter seal established between the bracket or backing plate (and sealant, of course). Fortunately, later model Sea Rays employ L brackets. Unfortunately, mine were not looking too pristine:

     I spent about half a day sanding and cleaning the brackets and backing plates. The transmissions were shimmed about 1/4" with spacer plates, so those had to be sanded too. Altogether, 20 parts had to be cleaned and prepared for clear coating. I shot them all at the same time:

     While the clear coating was curing, I prepared the stringers by cleaning them thoroughly, then cleaning out the holes where the bolts passed through. Fortunately, no evidence of water intrusion was found. The surveyor I hired last fall also commented on how dry the hull was, so this just confirmed his earlier findings. He had tested the hull at over 100 points, and found very low moisture levels throughout. In order to keep the boat as dry as possible, I have been meticulous in sealing every penetration, and coating the bilge with moisture resistant urethane paint. Hopefully, these efforts will pay off down the road.
     Once everything had cured fully, I reinstalled the brackets...

     All the locknuts, bolts, and washers are new . It almost looks ready for power...just a bit more painting, and a generator install to go...