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Sunday, March 31, 2013

Dealing with wave slap

Here's a project that can be filed under "things I wish I had thought to do before fitting out the interior". Once we launched the boat it became apparent that in certain situations there was a significant issue with wave slap under the swim step at the stern of the boat. This seems to occur when we have a certain size of wind wave or chop coming from astern. Because of the tendency for the bow to point into the wind when anchored, this is really only an issue when we are tied to a dock with the wind coming from astern. At our current slip, this occurs in the Winter, when weather systems blow through causing the normally westerly winds to veer to the South East. The picture above is a sunrise from our slip (looking roughly South East). With the swim step integral with the hull, this "dead space" caused the waves slapping under the stern to reverberate through the aft cabin. Since the sound was being transmitted directly into the hull plating, the solution was to dampen the vibration of the hull plate in this area. This space under the swim step is very close to being closed in by our interior paneling and cabinets. Not wanting to do too much experimentation due to the difficult access, I called Soundown and they helped me cut to the chase with the right solution. We ended up using their 1/4" vibration dampening mat which weighs about 2 lbs per square foot. I cut it to fit between the longitudinals and epoxied it in place with some recommended adhesive. Not a particularly fun job, but worth the effort. Initially, I just had the cut material laying on the hull plate and the difference was minor, however gluing the stuff down has made a significant difference in the wave slap. Now during the odd times when we do have waves coming from astern we find that the noise is lower in pitch, not as loud, and doesn't reverberate like it used to. It's still there from time to time, but not nearly as annoying as it was before. I think that once we have the aft cabinetry in place the noise will be even less bothersome. I may use some of the leftover dampening material in the bilge over the prop to reduce some of the noise from the running gear when underway. Last couple of pictures are before and after of the "living room" area forward of the galley and dinette. Since Spring is here, we set-up a workbench arrangement on the dock, moved a bunch of tools into dock boxes, and broke down the workbench/pile of  stuff that had taken over the middle of the boat. Lots more elbow room now.

Thursday, March 28, 2013

Fuel and Fire Prevention

These two seemed to go together so I'll put them in the same post. Our boat has six fuel tanks (forward port and starboard, aft port and starboard, keel forward, and keel aft) plus a 50 gallon day tank. This is a lot of tankage to keep track of and if you go back a ways in this blog (or search for "fuel") you'll find some posts describing our somewhat complicated fuel distribution system. Now that its all put together, we can transfer fuel between any two tanks, or to the day tank from any tank. Transferring from tank to tank allows us to trim the boat as necessary as we burn through our fuel supply. We can also directly feed the engine and the diesel furnace from any tank and return fuel directly to any tank. Most of the time we just transfer to the day tank as necessary and feed all machinery from the day tank. This makes it easy to monitor consumption (day tank is designed so that 1" on the site glass = 1 gallon). The transfers can be done with an electric pump, or with a hand crank pump. Either way, the fuel moves through a big Racor filter, and a fuel meter that counts gallons so we can keep track of how much we are putting where. So, the last part of the fuel system was the tank level gauges. As all our storage tanks are integral with hull and low in the boat, I opted for a Hart Tank Tender. This is a very simple and reliable system that uses a pressure gauge to read how many inches of liquid is in the tank. This is accomplished by running a thin nylon tube from the gauge panel in the wheelhouse to the bottom of each tank. To sound the tank, you pump some air into the tube with a mini pump on the gauge panel. The reading (in inches of diesel) from the gauge is then converted from inches to gallons using a chart  made up for each specific tank. When we built the tanks, I had this system in mind and installed 1/2" standpipes for the nylon tube fitting to enter the tanks. Here's some pics of some of the tank fittings that finished out the system. After a little tweaking with the distance between the end of the tubing and the tank bottom, everything seems to be reading correctly for how much fuel we estimated was in each tank from our first fill-up last fall.

I have also been working on fixed fire extinguishing systems for the engine room and the electrical cabinet. Both spaces now have fixed cylinders that will automatically discharge when the temp rises to 175 degrees or so. They can also be manually discharged with a pull cable from outside the compartment, which is a much safer way to deal with a fire in a confined space. The extinguishing agent FM200 does not leave any corrosive residue like dry-chem so is safe for all electronics and machinery. This means that you have a good chance of getting underway again at some point after fighting a fire with this stuff. I still have to hook up some parts of the electrical portion of the engine room system. This is a little black box full of relays that takes a signal from a pressure switch on the extinguisher and automatically shuts off all the machinery in the event of a discharge. This is so the running engine, diesel burner, etc. don't suck up all the extinguishing agent into the air intakes. Also you don't want to keep pulling fuel through the lines with a running engine, potentially continuing to feed the fire. The rest of our extinguishers are hand-helds which are spread throughout the boat. 
I'll probably get back to cabinetwork again this weekend and post some more interior shots...

Monday, March 4, 2013

Interior Pictures.

Well, its been a while since I posted here... we are still using our old (slow) internet connection on the boat and I just can't seem to find the time to sit down and post pictures. For now, I'm going to try doing the text on our home internet connection and uploading the photos directly from my phone using a blogger app. Winter is still with us, despite the dry weather here on the West Coast, so all of our efforts continue to be on the interior fit-out. I am determined to not live in a construction zone for years and years so most of our weekends are spent working on some aspect of the boat. I've been jumping around a bit, but recent work has included aft cabin cabinets and finish, completing the galley and dinette, and starting on the wheelhouse interior panelling and finish work. What usually drives the to-do list is "what materials am I tired of tripping over? One nice addition to the wheelhouse has been a tank monitoring system for our fresh, gray, and black water tanks. No more lifting hatches to sight the tanks - it's all on a digital read-out with alarms for high and low levels. The tank tender (below the digital gauge ) is for sounding fuel tanks. It uses air pressure to read how many inches of diesel are in each tank. Next to this is a table that converts inches to gallons for each fuel tank. I haven't hooked up the fuel tank end of this system yet but it is very simple in principle. The plywood that we were using for a dinette table was getting pretty gross, so I used some left over black laminate to make a temporary table thats a little easier to keep clean. Eventually I'd like to do some kind of cool inlaid wood top, but this will do for now. Also found some inexpensive patio furniture cushions that will get us by until we build some proper upholstered benches. I kind of like the jungle look. We continue to work on aft cabin and aft head cabinets. The cabinets shown are mostly raw wood still, but will darken up like the galley cabinets once I put some finish on them. Results are starting to show and it's great getting our stuff out of cardboard boxes. Also put in a neat little computer desk which I am sitting at to type this post. Definitely need to upgrade the lawn chair seat soon though. In the wheelhouse, we are using some more of the doug fir T&G for wainscoting. Above this (between the windows) will be painted plywood panels and mahogany trim. Speaking of which, I started ripping down some of the 4x4 and 2x3 pieces of salvage mahogany that I found out in West Marin a couple of years ago. I have no idea how old it is or where it came from originally, but looks like really nice stuff once you remove the grey weathered exterior. extraordinary deep red with lots of swirl and figure to the grain. These pictures don't really do it justice. Once its all ripped and surfaced, this will make nice trim and countertop edging. -PB