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Old 18 October 2015, 12:25   #11
zip
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I went out in the ocean for the first time this week from Mission Bay to the San Diego Bay.
I'm not sure how far it is, but It took two hours there and back at around 25mph, which includes the time it takes to get out of my bay, which has a posted speed of 5mph.
It was a little windy, with white caps and light chop, so I felt this would be a good test run for me.
The first thing I noticed upon exiting the channel is the hundreds of lobster traps, which are like land mines. Sometimes you only have a couple of seconds to react in order to miss them.
The SD Bay is South of MB, so you are going downhill/with the current/with the swell, or whatever the nautical term is.
My top speed was 27mph @ 2200 RPM. On both times I went out with Tom before I purchased, he was easily able to get boat up to 30, @ same RPM. I really need to figure this whole tilt and trim thing out. I have a couple of switches with lights on them, and basically just keep the outdrive all the way down. Whenever I try to lift it up a little with the trim switch, the boat slows down. 27 is still pretty good, but I would really like to hit that 30.
Since my previous boat was a Novurania 420, I see quite a difference in the performance. There really is no comparison. The 420 was a great little calm water boat, but my 7M is definitely going to make me more comfortable when I am 40 miles out at sea, and coming home in a small craft advisory. I can't believe I actually did that in my Novurania.
I got hit in the face a couple of times with a fair amount of water, so when I do get my t top, I will have a windshield incorporated in that.
The boat is real loud. It has a stereo with it's own built in amplifier, and volume needs to be almost maxxed to hear it. I have a couple of round speakers in a box at my feet. I will look in to mounting them, possible small external amplifier, and some box speakers incorporated in my t top.
No idea on fuel consumption. I guess I should use the dip stick to check that . I'm still not dialed on the whole correct air pressure thing. I know I have a pretty bad leak in the port rear chamber, which I have to air up around once an hour, but I have to figure what is the proper set up to make sure I am not under/over inflated. I have two foot pumps. one electric pump, and two gauges, so I should be able to make this work.
Came back late in the afternoon, and it was much rougher. I first kept it at same speed, and then finally reduced to around 20. I don't know if the boat was getting air, but I definitely was. I haven't latched the engine console, or rear box down, so when I hit the big waves, I went airborne, and both the covers lifted. I believe the boat can take far more abuse than I can, but I slowed down. I don't enjoy that kind of ride. I will now start latching those covers down.
All things considered, I feel it was a successful first ocean run, and the boat performed like I had expected.
I wish I could share some pics, but I still can't figure out why they come out sideways.
Happy Sunday to all.
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Old 18 October 2015, 21:58   #12
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Not familiar with the area so I google mapped it. Sounds like a fun run! I know you had a long wait to finally get a 7m so its good to hear a nice trip report. If you still had the smaller RIB, would you have done the trip in the same amount of time?
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Old 18 October 2015, 22:04   #13
zip
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Originally Posted by tworotorturbo View Post
Not familiar with the area so I google mapped it. Sounds like a fun run! I know you had a long wait to finally get a 7m so its good to hear a nice trip report. If you still had the smaller RIB, would you have done the trip in the same amount of time?
In flat water, I could have probably shaved a few minutes off of the time in the smaller boat. It was pretty quick, but I know I could not hold that speed in anything less than perfectly flat and calm conditions.
Once I learn how to work the tilt/trim functions correctly, I hope to be up to my target speed of 30mph at cruise.

Which one of your projects will hit the water first?
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Old 18 October 2015, 23:16   #14
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Fun! We went out of Ventura today heading for Anacapa and had to turn back. Couldn't get above 15mph without catching air. Decided it wasn't a family dive day The boat could go on but not a day to be out for fun.

so my understanding is that with the engine trimmed parallel to the hull will get you the fastest speed. I figured out where that is on my trim meter on land and verified it on the water, set the throttle and move the trim around, you will see your speed change.

Jason
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Old 18 October 2015, 23:59   #15
zip
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Jason,

Can you get up on a plane at 15?

With an outboard, don't you just have the one tilt up/down switch?

I have the two switches, with no gauges. My understanding is that the tilt switch is for the big up and down movement, like if you are going to put the boat on a trailer, and the trim is for the fine tuning.

I keep the boat in a marina, but I have it on an airdock. The entire boat is out of the water, and I can see the out drive. Do you think I should lower the out drive until it appears parallel to the hull, and try it that way? I would imagine I could put a level on it if need be, but might be able to do it by eye.
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Old 19 October 2015, 00:33   #16
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lower the outdrive all the way down and then when plane out raise it slightly until you see your mph raise up. You dont want to trim the outdrive too high

it sounds like you also have trim tabs on each side of the hull at the stern, is that correct?
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Old 19 October 2015, 00:34   #17
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Parallel to the hull puts too much hull in the water. Trimming up reduces the wetted surface (and friction) and therefore you obtain higher speeds (until you trim too high and the boats becomes unstable).

Zip, your numbers seem pretty close to what I'd expect - 27 mph @ 2200 rpm seems reasonable. I've got a spreadsheet somewhere on my computer and look tomorrow. You could calculate the prop slip and see if it falls in the expected range (variables to plug in - 1:1 transmission, 1.54:1 outdrive, actual rpm, and observed speed. That will give you prop slip.). Search my name - I bet I posted a table of rpm versus speed and prop slip.
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Old 19 October 2015, 08:12   #18
zip
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Originally Posted by Ribdude View Post
lower the outdrive all the way down and then when plane out raise it slightly until you see your mph raise up. You dont want to trim the outdrive too high

it sounds like you also have trim tabs on each side of the hull at the stern, is that correct?
Ribdude,
That's exactly what I do, but when I try to bring the trim up, the boat slows down.
I do not have trim tabs.

Tom,
OK, when I get a chance I will look for your chart. My cruise speed is actually closer to 26 though. What I don't understand is how the two times you and I went out, you easily hit 30 @ 2200 in both the bay and the ocean, and I am not able to do that. I'm inclined to believe that I just don't have tilt/trim at right adjustment. I only have around 5 hours in the boat, and I guess I will just have to continue experimenting.
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Old 19 October 2015, 11:12   #19
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The first thing I noticed upon exiting the channel is the hundreds of lobster traps, which are like land mines. Sometimes you only have a couple of seconds to react in order to miss them.
Still early in the season. This will go on through, what, February? March? Something like that. Then the abandoned traps' buoys will get coated with algae and be even harder to spot.


Quote:
The SD Bay is South of MB, so you are going downhill/with the current/with the swell, or whatever the nautical term is.
If you're talking long regular waves, it's swell. Wind generated local stuff is chop. Current is water moving in a direction en masse. "Downhill" generally means running in the same direction as swell. Some may use it (especially blowboaters) to mean downwind (which is not necessarily the same direction as swell.)



Quote:
I believe the boat can take far more abuse than I can, but I slowed down. I don't enjoy that kind of ride.
Most inflatables will take much more punishment than the pilot or passengers can (at least comfortably, which of course is a sliding scale.) But I know what you mean; looking back on how I used to run my boat when I first got it, I am much more judicious on speed in rough water now.

jky
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Old 19 October 2015, 15:49   #20
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You're pretty close to what I have on my spreadsheet.

Top data set is the back up aluminum prop I gave you.

Middle set is a 3 blade, 21" pitch that was 18 1/2 in diameter. Big prop, great fuel mileage. I wish I had tested it after I had adjusted the throttle cable - note I was only making 2580 rpm. Prop SOLD

Last set is what you have on the boat. In flat water, light load, I was getting 28 mph. 1 mph difference could easily be trim.
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