Prop Pitch and Cavitation
After all this time, I’m still having prop problems. When the engine reaches about 800 RPM, I can hear cavitation. How do I know that’s what it is? Well, one of my regular crew is a Navy boy and he said that’s what the sound was. Not only that, when we revved it up more, there what a strong vibration to the boat – more than I’d expect to be normal.
So I asked Scott at Electric Yacht what he suggested. He said to try decreasing the pitch on the prop.
Pitch is the distance a propeller will advance with one turn. So, a 10″ pitch means that the propeller will move forward 10″ with one revolution.[1]
The prop is a 13″ 2-blade Max Prop. If you check the specs on the thing, you can see that it’s fully adjustable: pitch and direction of movement. I had based the pitch I set it at to what it was before I took the old inboard off. Or so I think. I didn’t know that I could look inside and find the settings. So I measured the angle and found a formula online to calculate what the pitch was. The pitch was 12″. So we decreased it to 10.
What’s so bad about cavitation? What is it? Well Wikipedia defines it as
… the formation and then immediate implosion of cavities in a liquid – i.e. small liquid-free zones (“bubbles”) – that are the consequence of forces acting upon the liquid[2]
The problem is, those bubbles can cause pitting on the prop. Enough of this and you have a non-functional prop.
After decreasing the pitch to 10″, the vibration at high RPMs seemed to go away. But the cavitation sound was still present. So I turned to the wisdom of the CAL boat and electric boat forums. The comments attached are the responses I received.
What now? Well, we’ll try decreasing the pitch to 8″ and see what happens.
[1] http://www.propellerpages.com/?c=articles&f=2006-03-08_what_is_propeller_pitch
Sailing Books
I love books about sailing, those of the narrative variety. I don’t mind having around the ‘how to’s’, but I can’t read them from cover to cover. I do, however, enjoy stories about sailing adventures. Here, then, are a few I’ve read over the past year and my thoughts on them:
Bound for Roque Island – Sailing Maine and the World by R.j. Rubadeau. ISBN: 1935098330
Rubadeau is preparing his old wooden sailing vessel for what may be the last summer sailing the family does together. His daughter is married, pregnant, and living in Alaska. His son is finishing up a high school program on the high seas (what a way! wish I’d known about such adventures when I was a kid!) and getting reading to start college.
The book glides back and forth between the present time and stories of how he got into sailing and many of his early adventures. Thrown in is alot of advice on preparing the boat, and things he’d done right and wrong througout his sailing career.
A very easy read. I really enjoyed the trip! The time leaps didn’t leave me lost as to where we were. And I appreciated that he let it be known that this first person narrative was definitely his own viewpoint of events.
Two Years Before the Mast by Richard Henry Dana. ISBN: 1593082703
From every old salt to whom I mention I read this, I get a knowing smile. This classic was originally published in 1840 and is still a delightful tale. A young man is recovering from an illness that prevents him from continuing his college studies. At the time, it was felt that sea air had curative powers. As a member of a Brahmin family in Boston (the ‘old money’ families), he could have travelled as a companion to a wealthy friend and spent his time with little to do but find his own amusement. Instead, he signs on as crew on a sailing ship bound for California. The book is the story of his travels, and was the first sea narrative written from the point of view of a crew member; previous novels had been written by officers or by passengers.
The author explains every part of his voyage in detail, understanding that most of his readers will have no experience on a sailing ship. He describes the crew’s quarters – before the mast – and their conditions. He explains about ‘good’ officers and ‘bad’ officers that he serves under. He talks about his duties and his own progression from greenhorn to seasoned sailor.
But the most interesting, to me, part of the book, are his descriptions of the California ports that he visits: San Diego, Los Angeles, Monterey and San Francisco. It was fascinating to hear about these places 200 years ago, when they were still Spanish territory.
The author does return and complete his studies, and becomes an attorney. He is well known for defending sailors against brutal officers in court. He is also responsible for writing some of the U.S.’s early maritime legislation.
The link I’ve provided is to the free Project Gutenberg edition. But that version doesn’t include the illustrations and diagrams. The free Kindle and Nook editions do. But I think I may just break down and buy myself a hardcover version, just for the chance to re-read passages from it over and over again.
Tales of the Seven Seas: The Escapades of Captain Dynamite Johnny O’Brien by Dennis M. Powers ISBN:1589794478
This book, chronologically, takes off where Before the Mast ends. It tells the life of an Irishman who had set off to become an intern for an office job. On the way, he meets a sailing captain who regales him with his adventures. Much to the family’s chagrin, the boy signs on as crew on a sailing vessel and never turns back.
The difference with this book over the other is that O’Brien stays a sailor, working his way up to captaining many vessels, from sailboats to steam engines. His voyages take him all over the Pacific, to Hawaii and the Far East. We learn of his family as well as his adventures.
This is a fascinating book about an amazing man.
The Motion of the Ocean: 1 Small Boat, 2 Average Lovers, and a Woman’s Search for the Meaning of Wife by Janna Cawrse Esarey ISBN: 1416589082
This true story is about a woman who tells people in college that she’s going to live on a boat. Living in Washington state, I wouldn’t think that would be a big deal. But this person has never even been on a boat before. Fast forward through college, girl meets boy, girl loses boy, girl finds boy again and marries him. He has grown up with boats and, at some point, they decide to take off in said boat and sail to the Far East.
It is nice to read a book written by a woman who actually knows something about sailing. She describes its beauty, the frustrations it can be, especially on a long haul with many miles between ports and nowhere to go, and the fear when things go wrong.
This book is written as a series of essays. There is a timeline to it, but not the flow that a novel should have. Esarey writes stories for sailing magazines, so I guess she’s still more comfortable with that shorter format.
Sex, Lies and Spinnakers by Steve Van Slyke ISBN: 0982554907
This is the only fiction book of the bunch. This story is also about a couple that decides to go cruising to the Far East. In their case, they’re going to follow friends down to Mexico and hang out for a bit before they determine if they’re ready to cross the ocean.
But, in Mexico, the friends they’re sailing with are murdered. A local is arrested for the crime, but neither our protagonists nor the police chief believe the local guy did it. But it’s bad for tourism to say otherwise.
That means one of a handlful of Americans must have done it, all cruisers themselves. And they’re all heading east. So our protagonists decide to follow and try to figure out who the murder(s) are.
I liked the first half of the story. It was well written. There was a definite sense that the person knew what they were talking about regarding cruising and boats. The interaction between the characters was good. But the second half of the book was difficult to read. It’s as if it was written by another person. The characters move from being very 3-dimensional to being very flat. The personalities change with no good transition to show how/why. I’m not sure whether it’s because the author should have just stuck with a good sailing story because he didn’t know how to write a good mystery, or because he got tired of the novel and tried to get too much in just to finish it.
[Top]Christmas Parade
There are Lighted Boat Parades throughout the Hampton Roads region. Each happens the first Saturday of December (weather permitting). Normally I travel on Dave’s boat in the Hampton parade. But this year, Dave and Petra are enjoying sunny Key West for the season. So, when Bette broached the subject of my doing the parade with my boat, I thought, “Why not?”
I’m on hold right now, waiting on word of my new contract starting. So it’s been difficult to plan much of anything. It’s like being on call – you have time to do all sorts of projects in the area. But it’s difficult to plan anything that will require leaving town, or may require long term planning of any sorts.
I missed the deadline for getting my name/boat in the program. That was the first part of November. See: ‘on call’ above. :-/ So this turned into one very long day!
In the morning, I moved the boat from Wormley Creek up to the Yorktown Riverwalk piers. It’s a short ride. But that morning, there were 15+ knot winds (there were whitecaps) and 2 to 2-1/2 foot waves. It wasn’t dangerous. But I’ve done enough of these rides and I really don’t enjoy them. I really wish the weather in the morning had been better.
I’d tried hailing the dockmaster when I was about halfway there, about 9:30. There was no answer, so I left a message on his answering machine. I wish I’d rechecked the website. In the winter, the dockmaster is only there from 10 – 4, Thursday through Monday.
I arrived about 5 after 10. I didn’t hail the dockmaster again. Since I was by myself, and the water was rough, and the tide and current make it a pain in the ass to get into those piers, I figured I’d do my best to park myself, then look for him once I got in. But he saw me pulling in and came to give me a hand. Of course, I didn’t dock it where he originally wanted me to. The situation was such that I was happy to just get it tied up.
Lesson one for the day: check the times the dock is opening, especially if you’re alone.
Lesson two: try to get some help when pulling into Yorktown Piers, whenever it is!
I got a ride back to my car from Bette, who was there for the craft fair going on in town that day. She headed back to the craft fair; I headed out to get a generator, then home to prepare for that night.
I was lucky; there were generators available. And at a good price, too! It only cost me $35 for Saturday afternoon through Monday morning from ABZ Rentals. That’s cheap enough, I may keep it in mind when taking some longer cruises next year.
I headed home, made soup and hot buttered rum mix, put both into crockpots and headed back over to the boat. The crew were going to meet me about 2 p.m. to help decorate. I arrived, unloaded everything except the generator and hauled it over to the boat. Wendy helped with the last of it. We got a dock cart from the Dockmaster and brought the generator over. I wanted to wait until someone else arrived before trying to get it aboard. I thought we’d have to use a halyard to bring it aboard. But Paul was able to lift it on the deck without a problem.
The rest of the crew arrived and we finished the decorations. There were a few pictures taken during the daylight of the boat. Unfortunately, I haven’t been able to find a picture of the boat lit up or in the parade.
- Lighted Boat Parade 2011
Courtesy of Paul Gregory
The wind was expected to die down about 2 in the afternoon. And it did. In fact, although it was cold – about 40 degrees – it didn’t feel too bad since we had no wind to deal with. Not only that, the river was smooth, which made for a nice ride.
I fed the crew soup before we headed out, so I wouldn’t have to worry about it spilling on the trip. The crew shared in the hot buttered rum on the trip. I waited until we returned to have any myself.
We waited for the announcement that the boats were gathering for the parade, and kept an eye on the Wormley Creek channel, from which many of them would emerge. We saw a few boats gathering, but not that many, so I finally asked Jodi to hail them and find out what was going on. Well, the boats had started getting into place. Doug asked us to head over and let him know when we’d arrived. We did, and he said to just find ourselves a place in line, which we also did. I felt sorta bad ‘cutting in line’, but that seemed to be the way it was done.
So we all took off and the parade began. It went down Sarah’s Creek, which we skipped, because I didn’t want to get stuck in the shallows, in front of the crowd at Gloucester Point, under the bridge – again skipped it because all the other sailboats were – then in front of the Yorktown piers. Then we circled in front of Gloucester Point and Yorktown again before pulling up in front of Yorktown, making noise and showing off.
The decorations blocked my view of what was directly in front of me. That wasn’t too bad most of the time. But, at one point, I got quite a bit behind the boat in front of me – I swear he sped up, but I don’t know for sure. We were hailed on the radio – they asked if we were still in the parade. So I sped up to catch up.
Lesson three: keep the line of sight clear with the decorations, and keep a good distance behind the boat in front of you.
We pulled back into the Yorktown piers when it was over. One of the volunteers helped us to tie up. Good thing, too! In the morning, after I’d left, a huge yacht had pulled in behind me. Glad I wasn’t there when he did – I’m sure I’d have had a heart attack. One of the passengers said I probably would have, since their bow when over my cockpit!
So, with the help of the young man on shore, we were able to park again where we’d been. Everyone took a break and warmed up by the bonfire on shore. Then we all sat in the cabin, ate the snacks that Bette and Jodi brought along, and finished up the hot buttered rum.
The next day, Erik and I came just before noon and picked up the boat. He drove while I started taking things down. He helped me once we got parked in the slip and we finished in no time.
I’d like to do this again next year. But I think we’ll stay at Wormley Creek. There wasn’t enough activity going on in Yorktown to really warrant being there. Besides, Pam and Doug had food and drinks for those who returned!
[Top]Watching the Wind Come In
I spent last Tuesday doing something I’ve never been able to do: spend *all* day sailing, in no hurry to get anyway. Usually, if I’m out for some pleasure cruising, there’s a time limit because the person I’m with has to be somewhere by a certain time. If I’m all day on the boat, it’s because I need to get it from point ‘A’ to point ‘B’.
But Tuesday was different. I’m between contracts, so my time is (mostly) my own. The weather reports showed last Tuesday as what may be our last really nice (read: temps in the upper 70’s) day of the year. Wednesday, it was to rain all day long. Days after that would show highs in the 60’s. Not bad, I know. But not the warm sun on your face almost perfect temp sailing weather.
I did have a goal in mind. I was heading out to New Point Comfort lighthouse again, at the mouth of Mobjack Bay, on the far side of Gloucester. It’s a pleasant little ride and not extremely far away.
The trip was beautiful. I had to motor most of the way out of the York River. But, as usual, when I reached the mouth of the York, the winds picked up and we were sailing. The direction was even good to sail most of the way over to the lighthouse.
The way back, as usual, was a bit challenging. It’s shallow between Mobjack and York River. There’s a cut through that you can take, but it’s narrow and I often don’t see the markers. I timed the trip so I could do this during high tide, and this helped. But I did keep a close eye to my depth finder and Navionics disply. I did get nervous as the depth got down to 13 feet and lower. I think it stopped at 9 before it started going up again.
Once I reached the York again, I saw an interesting site. I could see the wind patterns on the water.
Now, I know the theory of this, and I know what you’re supposed to look for. The water appears darker where the wind is stronger. Where whitecaps appear, the wind is stronger still. But I had never seen it so clearly as I did that day. There were ripples where I was, and there had been most of the day, given the perfect wind I’d been riding in. But ahead of me, the water appeared darker, and it looked even darker still further on.
So I was ready, and I adjusted for it. I let out the sails before I reached the darker water. I gauged the wind and adjusted accordingly. It worked well, I felt in control of my boat. Before I reached the whitecaps, I turned into the wind, pulling in the main so it didn’t bang back and forth, turned on the autopilot, and pulled the jib in partway. I let the main back out, turned off the wind, and headed into the whitecapped water.
I spent my time getting back the channel that led to the marina. It felt good to be out there practicing my skills.
And it just felt good being sailing and not worry about the time.
[Top]Deconstructing a Bad Race
Last Sunday was the first race of the Frostbite series. It lived up to its name. It was cold. It was wet. It was too windy. The only thing missing was high waves.
I showed up about an hour early, to clean up the boat a bit. With all the work I’d done this summer, I never really had the time to put things away. So I gathered up tools, and moved things around that were sitting on the galley counter. I knew it might be a bit rough and I wanted to minimize the mess in the cabin.
It started to rain pretty heavily before Paul and Grant arrived. But it was short lived. The sky didn’t clear up, but it wasn’t quite as black. So I had hope that the race would go well.
Paul and Grant are usually good about arriving a bit early. So when they hadn’t shown up by about 15 minutes before we planned on leaving, I thought they might have decided against coming, having seen the weather. But they arrived. We all put on our foul weather gear and headed out to the starting line.
I hadn’t finished tightening the bolts on the engine mounts. So I had Paul take the wheel while I went below and took care of that. I also wanted to take a look to make sure the engine looked good and that the stuffing box was performing well. A big OK on both fronts, so I headed back up.
I tend to be very cautious still. 3 years has not made me feel like any sort of expert yet. So when the weather gets rough, I’d rather not put out the full sails. I feel more in control that way.
But as we started out, the wind wasn’t too bad, although we could see the next band of rain headed our way. So we put the mainsail up all the way, and headed towards the starting line. The wind had picked up a bit by the time we reached our buoy, and we’d had our first band of rain hit us. I only have one jib, but it’s a roller furler. So we tied off the roller furler in such a way that only 1/2 the jib was released. We winched it in and got ready to start the race.
We were in a good position. I was psyched. We were, however, the least experienced one out there. And, as I already mentioned, I do tend to be a bit overly cautious. So we hung back a bit. I don’t mind being a couple minutes late over the start; I’m not going to come in first, so why risk ramming someone else going over the starting line.
Time was called. The race was to be around another buoy and back. We played follow the leader, to get a better idea where to make our turns.
First leg went smoothly and we were moving well. I wasn’t sure how well we’d be able to follow the leaders; we were a bit downriver from them and it would depend on how the current took us whether we’d get too close to the refinery’s docks. But no, we weren’t too close and we turned at the point that the others did.
Second leg, I could see a few white caps ahead, so I knew the wind was going to pick up. And it did. But it was very isolated and we came out of it fine. We put the jib out more to give us a bit more power and and made the next tack.
Third turn. Again the winds were picking up. This time a bit stronger. On top of that, I saw one of the other boats rounding out, so I knew they were having a few problems with the wind, too. Not only that, but a second boat was heeling over enough to wash windows.
I got a bit nervous. We’re out there for fun, not to make it dangerous. And I didn’t want to get in over my head. So I asked Paul to reef the main in. He went to do so. He was having trouble doing so, so Grant went to help him. At that point, I realized I should have steered into the wind to make it easier for him. But I couldn’t do it then; it would have been too dangerous. I was afraid that I’d lose one or both of them over the side.
We had a big gust at that point, and it pulled the boat over quite far, although briefly. At that point, I called Grant back to the cockpit to pull in the jib and I started the motor. There was too much wind; I didn’t feel comfortable and I wanted to head back.
We brought the jib in. Paul had to help Grant because the wind was quite strong at that point. I then turned the boat more into the wind and Paul brought down the main.
We tied everything down and headed back to the docks. We called the committee boat to let them know we were out of the race. As we headed back in, the wind died down again. In fact, it looked like the other boats were having a heck of a time making it around the buoy and back to the finish/start.
So what should I have done? I’ve been thinking about this for a week.
I still think I should have brought the main down, if only briefly, if I felt that I couldn’t control the boat in the given winds. But I should have turned into the wind before I sent Paul up there.
I should have insisted we all wear life preservers. If there was even a hint of a chance of someone ending up overboard, especially as the water is getting colder, I should have been prepared.
I should have looked head to see if this, like the other two rain bands that hit us, was going to come and go as well. We might have been able to in the race if I’d paused long enough, or let the sails down long enough, to let it pass, then continued as before. As I said, we weren’t going to win. But that way, we would have at least finished.
Well, there’s always next week!
[Top]