July 11 - 13 2011
I got to the boat at 10pm on Monday and went right to sleep under the fan. I got up early and started grinding away the rust spots on the keel. I made some progress, but the grinder from Harbor Freight (used once before for the previous keel work two years ago) started overheating and spitting out red plastic pieces. I got most of it cleaned up except for some stubborn and complex areas around the top. Kenny came over and looked at the rust and said I needed to use a hammer. He loaned me a Chipping Hammer, and wow it really knocked the chunks of rust off. When I got all that done he brought the welder over and filled in the holes and ground them smooth. I was pretty much covered with grinding dust and fiberglass so I took a shower, drank water, and rested in the air conditioned lounge.
Later that afternoon Randy set up the air hose so I could sand blast the areas to get them ready for priming. Just as I was getting started the air hose popped off the fitting and started jumping around like a crazy snake. Randy came rushing back when he heard the blast from the hose. He trimmed the ragged end and reattached the hose with two opposing clamps and that held for the rest of the job.
The sandblasting was fun. It really textured the metal and cleaned it 100%. Since the heat index was well over 100, I was pretty well covered with sweat and grit and rust by the end. But it was necessary to prime the bare metal immediately. Randy mixed the primer up before he left. I needed a 1.5" brush, but all I had was the little .5" acid brushes. I taped 3 of them together and it worked very well. I got the whole thing primed as it was getting late (and cooler). Unfortunately there was so much sweat and grit on my glasses, and the sun was glaring on them that I missed a little spot of primer right near the forward port lifting ring and I ground with the grinder and primed but did not sandblast 4 sq. in. on the forward port side right near the top of the keel. I'll see if it rusts in either of those spots in a year or two.
Susan and Bill from Osprey, who we met in Coconut Grove, Miami, and then a couple of times in the Bahamas, showed up at the Boat Yard and invited me to dinner at their Condo. When the priming was done I showered and drove to Atlantic Beach to visit and have dinner with them.
Wednesday morning it was hot before the sun got up, and I had trouble getting started. But I had to get the next coat of primer-2 on before I could start the epoxy, and the timing was important. All the solvent needed to evaporate, but the epoxy needed to still be a little tacky so the final layers would adhere to the primer layers. I got the second primer layer on by 10:00am and expected to wait till 3:00pm to start the final epoxy and glass layers.
With the sun killer-hot I made a little "A" frame to support a line from the radar mast to the bow and was able to mount my shade tarp over the cockpit. The silver fabric reflected most of the heat, but was so hot that I got burned when I accidentally touched it.
With shade now up, I switched projects and began to work on the toe rail for the bridge deck that will keep the cushion away from the traveler car. First I had to grind a curve into the bottom of the tow rail so it would fit the curve of the bridge deck. That went very smoothly with a 60 grit belt on a belt sander. Then I marked the location for the toe rail on the bridge deck and drilled 6 holes for the bolts down from the top, but not through bottom layer of the bridge deck. Then I fitted a little "L" shaped knife into the drill and used it to cut up the foam between the top and bottom layers of the bridge deck at each hole. Then I filled the voids around the holes with epoxy resin. The purpose for this is if water gets into the holes it can't migrate through the foam between the top and bottom layers of the bridge deck. Also it prevents the foam from getting crushed when the bolts are tightened.
Now it was 1:00pm, and the primer was ready for the final coats of epoxy. It is now about 100F and the epoxy is setting up in about 3 minutes. Talk about working fast. I cut out about 3 pieces of fiber glass, about 15 sq inches or so, and that was about as much as I could do with one pump measure of epoxy. By the time I got the next section done the first was cured and ready for another layer. The result was that I three layers of epoxy done and sanded by 3:00pm. Under cooler conditions I would have had to wait for 2 six hour curing periods between layers of epoxy. So now the keel is protected and sealed and ready for me to put on another final smooth protective layer in the high load contact area and re-attach the glide rails at the top of the keel.
3:00pm, time to finish off the toe rail. Now that the epoxy in the holes was hard I could drill the holes all the way through. Then I placed the toe rail in position and drilled one hole up from underneath. Then I tapped the hole to accept a bolt and bolted it in place so I could drill the next hole. Then removed the toe rail and tapped the second hole and bolted it back in place with two bolts. With it held securely by the two bolts I drilled the rest of the holes, removed it again and tapped those holes. Finally I coated the bottom with Life Caulk and bolted it for the final time. Unfortunately, two of the holes didn't align up exactly right and the bolt wouldn't go in. In desperation I took the tap and ran it up through the bottom and it re-cut the threads so the bolts went in securely.
My two main projects were done and I wanted to get home. I rushed to get everything put away. I had to leave by 4pm so I could get to the sail maker to leave the sail for repairs. I did get everything put away, but there was no time for a shower if I was going to get there on time. I called ahead, and even though I was 20 minutes late (Garmin GPS didn't count on the ferry trip being so slow), they waited for me and I dropped off the sail and drove home stopping only at King's Barbecue for dinner. ($6.99 buffet) I got home just before 10pm.
I wish I had taken some pictures -- but it was way to hot to think about anything but getting done.
Friday, July 15, 2011
Thursday, July 14, 2011
Get the Keel Ready for Welding
To ready the keel for welding I needed to clean off the bottom paint so I could identify and remove the epoxy that was covering any rusted areas as well as get rid of any diesel that was in the tank.
I used the mesh sanding screens that are used for drywall sanding to remove the bottom paint. I clean the screen in water and wet sand the keel. This keeps all the toxic paint in the water which can be discarded with other toxic chemicals. I got the main rusted areas uncovered. When I tried to remove the diesel I discovered that the diesel level was already below the pickup tube. I inserted a .25" copper tube down the pickup tube to get the remainder of the fuel, but it clogged up the copper tube, so I was unable to remove the additional contaminated fuel in the bottom of the keel. I'll see what Kenny wants to do about that next time.
The other project is to attach the TackTick wind indicator to the top of the mast in two positions: first at the very top so it will give accurate information on any point of sail, and second in front of the mast about a foot below the top so it will give good information only when pointing to windward, but won't be in danger of being damaged by a low bridge (unless it is really low). The RayMarine wind instrument attaches to the rear radar mast and is inaccurate when close hauled, so having the TackTick in front of the mast and the RayMarine at the stern of the boat will give me accurate data on all points of sail.
I previously had made a bracket that extended above the top of the mast, but while it worked, it blocked the tricolor mast top light. I was able to take the original bracket and using a small piece of it off the top make a very simple bracket that attaches to the top of the mast under the tri-color light using the same machine screws, and taking the old bracket's bottom section, the piece that attached to the mast, make a second bracket that attaches below the top using the same attachment holes. I'll post pictures next time I visit the boat.
I used the mesh sanding screens that are used for drywall sanding to remove the bottom paint. I clean the screen in water and wet sand the keel. This keeps all the toxic paint in the water which can be discarded with other toxic chemicals. I got the main rusted areas uncovered. When I tried to remove the diesel I discovered that the diesel level was already below the pickup tube. I inserted a .25" copper tube down the pickup tube to get the remainder of the fuel, but it clogged up the copper tube, so I was unable to remove the additional contaminated fuel in the bottom of the keel. I'll see what Kenny wants to do about that next time.
The other project is to attach the TackTick wind indicator to the top of the mast in two positions: first at the very top so it will give accurate information on any point of sail, and second in front of the mast about a foot below the top so it will give good information only when pointing to windward, but won't be in danger of being damaged by a low bridge (unless it is really low). The RayMarine wind instrument attaches to the rear radar mast and is inaccurate when close hauled, so having the TackTick in front of the mast and the RayMarine at the stern of the boat will give me accurate data on all points of sail.
I previously had made a bracket that extended above the top of the mast, but while it worked, it blocked the tricolor mast top light. I was able to take the original bracket and using a small piece of it off the top make a very simple bracket that attaches to the top of the mast under the tri-color light using the same machine screws, and taking the old bracket's bottom section, the piece that attached to the mast, make a second bracket that attaches below the top using the same attachment holes. I'll post pictures next time I visit the boat.
Sunday, July 10, 2011
On the Hard at Bock Marine near Beaufort NC
We got to Bock Marine on Monday morning. We expected to get ready to haul Prestissimo for a couple of hours and then to ask Dirk at Bath Harbor Marina to pick us up in the van I left there in January so we could drop him off back in Bath on our way home. It didn't work out quite that way since the travel lift and crane operator was off for the day.
The delay turned out to be just what we needed since it took us all day to get everything ready to leave the boat at the yard.
Then they drove the boat over to the place where they wanted to leave the keel.
The travel lift had no trouble lifting the boat high enough (after they shortened the straps) to remove it from the keel.
Then they took Prestissimo to her home in the yard and used the crane to remove her mast and lay it along side.
Prestissimo is in a good spot for the summer. She has shade till nearly 11:00 am.
Monday, July 4, 2011
Problems with the Genset
Well the genset worked for a couple of days, then it overheated and shut off on its own without doing any damage to itself or anything else.
After it cooled off it would start up and run from anywhere from all day to just a few minutes. Calls to Volvo service centers and Polar Power didn't provide any helpful information so I just continued to document the conditions around the overheating to find out what the problem might be.
The most interesting measurement was the exhaust water temperature. Under normal operating conditions it was about 10 degrees F warmer than the sea water, but just prior to overheat shutdown the raw water exhaust was the same temperature of the sea water. This indicated that the problem was with the heat exchanger i.e. the sea water was passing through the engine without picking up any heat in the heat exchanger. This could be caused by two situations: either the thermostat was causing the coolant to bypass the heat exchanger or the coolant was being blocked from going through the heat exchanger.
When we got to Jacksonville FL we had a Volvo service mechanic check out the genset, and he found no problems, but when researching the problem decided that the problem was the high temperature cut-out was set too low. We changed the cut-out temperature and that seemed to solve the problem. That is until we got to Miami.
In Miami I flushed out the engine and got out about half a teaspoon of metal shavings (which the folks at Polar Power said was normal for a new engine) and replaced the thermostat. Again that seemed to solve the problem, but two weeks later, in the Bahamas, on the way to Nassau, it overheated again, and would not restart for more than a minute.
In Nassau I flushed out the coolant and raw water lines very thoroughly and got out some more metal shavings. Again this seemed to solve the problem for a month. But as we were leaving Georgetown, Exhauma it overheated again. This was the second time it overheated just as I was thinking that since the wind had piped up it was time to shut the genset off and I suspected that healing might be the problem.
It wasn't until a week later when we were sailing from Eleuthera to the Abacos across the NE Providence Chanel that I really narrowed the problem down so it could be solved. We were motor sailing into the wind. Ruthie was down below watching the temperature. We were on starboard tack which is where the reservoir for the coolant is below the heat exchanger. After a few minutes the temperature began to rise and just before the overheat temperature Ruthie told me to tack. As soon as I tacked the temperature went down within less than a minute. We repeated this many times. We also tried keeping the boat on starboard tack and let it cool off then, when we restarted the engine it overheated immediately.
Here is an email I sent to Polar Power after these tests:
My working hypothesis is that an air bubble is being sucked in from the reservoir when the boat is healing and as the air fills the tubes in the heat exchanger the cooling is reduced until it finally overheats. The solution then would be to move the reservoir above the engine so that it is always above the heat exchanger at any angle of heal.
It wasn't until we got to Charleston SC that I was able to find the small diameter heater hose necessary to move the reservoir. When I finally relocated it to the bulkhead above the engine again the problem seemed to be solved. This is the email I wrote after testing the new location:
As of this writing Prestissimo is in a boatyard until October, and further testing won't happen until this fall, but I believe the problem is finally solved.
After it cooled off it would start up and run from anywhere from all day to just a few minutes. Calls to Volvo service centers and Polar Power didn't provide any helpful information so I just continued to document the conditions around the overheating to find out what the problem might be.
The most interesting measurement was the exhaust water temperature. Under normal operating conditions it was about 10 degrees F warmer than the sea water, but just prior to overheat shutdown the raw water exhaust was the same temperature of the sea water. This indicated that the problem was with the heat exchanger i.e. the sea water was passing through the engine without picking up any heat in the heat exchanger. This could be caused by two situations: either the thermostat was causing the coolant to bypass the heat exchanger or the coolant was being blocked from going through the heat exchanger.
When we got to Jacksonville FL we had a Volvo service mechanic check out the genset, and he found no problems, but when researching the problem decided that the problem was the high temperature cut-out was set too low. We changed the cut-out temperature and that seemed to solve the problem. That is until we got to Miami.
In Miami I flushed out the engine and got out about half a teaspoon of metal shavings (which the folks at Polar Power said was normal for a new engine) and replaced the thermostat. Again that seemed to solve the problem, but two weeks later, in the Bahamas, on the way to Nassau, it overheated again, and would not restart for more than a minute.
In Nassau I flushed out the coolant and raw water lines very thoroughly and got out some more metal shavings. Again this seemed to solve the problem for a month. But as we were leaving Georgetown, Exhauma it overheated again. This was the second time it overheated just as I was thinking that since the wind had piped up it was time to shut the genset off and I suspected that healing might be the problem.
It wasn't until a week later when we were sailing from Eleuthera to the Abacos across the NE Providence Chanel that I really narrowed the problem down so it could be solved. We were motor sailing into the wind. Ruthie was down below watching the temperature. We were on starboard tack which is where the reservoir for the coolant is below the heat exchanger. After a few minutes the temperature began to rise and just before the overheat temperature Ruthie told me to tack. As soon as I tacked the temperature went down within less than a minute. We repeated this many times. We also tried keeping the boat on starboard tack and let it cool off then, when we restarted the engine it overheated immediately.
Here is an email I sent to Polar Power after these tests:
I have now identified a very specific and repeatable way to initiate
and correct the overheating of the Genset.
When the boat heals 10 degrees to port (toward the oil dipstick) the
temp goes from a stable 180 degrees F to about 220 F. Further healing
to about 15-20 degrees will cause the temp to fluctuate into the 230 F
range until one of the spikes goes to 239 F and it shuts off.
At any time when the temperature is high, leveling the boat or healing
to starboard will bring the temperature into the 180 F range. The
temperature drop is immediate and dependable.
The raw water exhaust volume remains constant at about 6 gal. per
minute. The coolant level in the expansion tank is at the minimum
line when the engine is cool and at the max line when the engine is
hot. The oil level is nearly full.
The specifications allow for a 30 degree angle of operation (operation
manual p. 68). The overheating usually occurs within 15 minutes of
healing at 15 degrees and within 5 minutes at 20 degrees. The cooling
starts immediately upon tacking and is back to the 180 degree level
within 2 minutes.
My working hypothesis is that an air bubble is being sucked in from the reservoir when the boat is healing and as the air fills the tubes in the heat exchanger the cooling is reduced until it finally overheats. The solution then would be to move the reservoir above the engine so that it is always above the heat exchanger at any angle of heal.
It wasn't until we got to Charleston SC that I was able to find the small diameter heater hose necessary to move the reservoir. When I finally relocated it to the bulkhead above the engine again the problem seemed to be solved. This is the email I wrote after testing the new location:
I believe the genset overheating problem is solved!
I moved the reservoir to a location two feet directly above the genset. The temperature was rock steady at 187 F while we were in gusty conditions on starboard tack with a minimum 10 degree heel and up to 20 degrees during gusts for about 20 minutes.
I hope my celebration isn't premature, I won't really know for sure until I have until I have a sustained rough heal to port, but I don't believe I will have these testing conditions before I put the boat on the hard for the summer, and I wanted to share this good news.
Two other changes that I've noticed:
The temperature does not fluctuate it stays at 187-190 F (it used to range from 170 to 220).
The cooling fan shuts off shortly after the engine stops and does not come back on. (Previously it would come back on within a minute and stay on for nearly an hour. The "Auto Vent Temp" is set to 195 F.)
As of this writing Prestissimo is in a boatyard until October, and further testing won't happen until this fall, but I believe the problem is finally solved.
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