What's "Level"?

[garyf]

I'm curious what y'all do when installing things that you'd usually take some care to "level" if you were installing them in your house or other land-based environment.

I mean, I get it - it's a boat, and "level" depends on the weight distribution within the boat... any motion of the surface of the water... speed you're going (on plane, etc) and so on.

Even sitting at home on the trailer, I really don't know how well things compare with being on the water - depends on how well the boat is centered/seated in the bunks, how far I have the tongue of the trailer jacked up, etc.

So - what if anything could I use as a reasonable reference for "level"? Can I assume the counter tops and/or table top in the cabin are supposed to be approximately "level" when the boat is sitting in calm water and 'factory' loaded?

Just curious what others do in this regard. The applications I'm thinking of don't have to be precise - I'm leaving my machinist's level in its case - but I'd like to at least use a common and reasonable reference... if that makes sense?

P.S. I'm not talking about anything that needs to be installed on a gimbal or anything, either... they'll be permanently attached to the boat, just wanting them to be "level" relatively speaking to other "level" things.

 

[srbaum]

Gary,
I am finicky about keeping my boat level and trim during all times underway. On my 22 and now my 26, I installed a stick on level, above the center forward window an another over the starboard front window, about center.
I had the boat in the water, when I installed them and used the flat surface on the center of the console and a regular level and used my body weight to get the level, where I thought it was good enough, then in installed the small level gauges.
It is nice to cruise and with a quick glance at plane, to adjust my engine (I have a Permatrim) and trim tabs, to keep the boat where I consider it properly trimmed.
These are the levels that I used. I prepped the fiberglass surface above the windows with denatured alcohol.
https://www.tractorsupply.com/tsc/produ ... of-2-306-r

 

[Foggy]

Exactly level at sea: It's purely subjective, not critical since, most of the time
underway, you're not 'level' and are constantly moving around in 3 planes - pitch,
yaw, and roll.

Even your expensive electronics and old world compass cannot keep you 'exactly'
on course either.

Here, close works. Go for whatever makes you comfortable.

Aye.
Grandpa used to say, "Don't get lost in meaningless minutia."
Grandma used to say, "Perfectionism only leads to disappointment."

 

[hardee]

WOW, level on a boat, now there is a can of worms.

I have a good friend who does interiors on high end boats, and even he doesn't have the answer to that, but he leans toward parallel, perpendicular and plumb.

Then you have fore and aft or abeam.

In my boat, I use the bottom of the front center window and use that as a guide to "level" for abeam. For for and aft, the counter top is parallel to the bottom of the side windows, and rarely is it parallel to the water outside unless I am at anchor. So, things that get mounted are parallel with either of those planes.

But, it's your boat, so what ever floats it, is probably level. What ever is comfortable to you eye will probably work.

Harvey
SleepyC :moon

 

[Foggy]

Aaahhh. I remember now.

"She had curves above and below but a straight keel.
And, her decks were well worn but her bilge was kleen."

Priorities are important.

Aye.

 

[thataway]

I also use the stick on levels--one just under the helm seat window for fore and aft trim, and right behind the wheel for lateral--side to side trim.

Yes, the counter surfaces are as close to being level when the boat is on her lines. As I moved things around the boat, we try and keep her "level". But even in the 25, more so in the 22, if Marie is going to step outside to the cockpit, I ask her to notify me, and let me know what side she might be standing or sitting on, so I can have the trim tabs appropriately adjusted. I like having the "position" lights on the Trim tabs, so you have a fair idea of how much tab there is.

Does this mean I run the boat level for and aft? No, what ever is the best "attitude" for the sea conditions.

 

[PNW_Wesley]

Prior to installing my radar dome, I downloaded lots pictures of Dory's that were side-on views. I imported them into PowerPoint, and drew a line along their roof line. PP then gave me the fore-aft pitch angle of the roof. While power settings and sea conditions affect the pitch, the majority of the boats I analyzed were in the 6 degree nose-up range, at a wide range of speeds.

This example is 7 degrees nose up.



On my boat, the side window sills are parallel to the roof. I taped my phone to the stbd sill, and via an app, measured the pitch angle through the full range of engine RPM. I recorded the pitch while increasing and decreasing the RPM. I used this method on several outings, with various sea conditions. The average of more than 70 measurements was close to 6 degrees nose up. The pitch at the speeds we most often cruise at is 6 degrees.

When it was time to chose a wedge for the dome to sit on, I chose 6 degrees down.

I can keep the roll axis fairly level by shifting my cargo totes in the aft cockpit.

When I'm in the fog on the Columbia, I like knowing that my dome is as level as I can make it. There are lots of things to bump into out there!

 

[thataway]

The horizontal beam of the radars is about 15* above and below the horizon. One consideration is that in dense fog one probably will use prudent seamanship, and be running at a much lower speed. This the boat will be more closely "Level". Because of this, I use a 3* angle for mounting radar.

 

[colbysmith]

All depends. If installing stuff inside the boat, I guess I use the countertop or ceiling as level. If installing stuff in the cockpit, I use the gunnels as level. Decals (boat name and number, level with the bottoms of the windows or top of the bow's sole. However, when installing my radome, I just took a swag and positioned it with the front a little lower than the rear. Due to the fact that rather I'm at displacement speeds or on plane, the boat is usually bow high.
Colby

 

[T.R. Bauer]

I don't make anything level really. I know this sounds nuts, but I try to make everything relatively level to everything else because I know nothing else is really level in the dang boat when I install stuff. Level underway? Good luck keeping that perfect. I think close to level, comfortable, and safe are probably enough.

 

[NORO LIM]

The horizontal beam of the radars is about 15* above and below the horizon. One consideration is that in dense fog one probably will use prudent seamanship, and be running at a much lower speed. This the boat will be more closely "Level". Because of this, I use a 3* angle for mounting radar.

Ditto. Night time and fog are the two times when radar mattered most to me. If I had to run in either condition, I was likely to be going very slowly.

 

[PNW_Wesley]

One consideration is that in dense fog one probably will use prudent seamanship, and be running at a much lower speed. .

Bob - I will assume that you are not implying that I run at a speed that reflects imprudent seamanship.

My choice of optimum dome tilt was based on actual pitch angle measurements throughout MY boat's speed range, which includes a prudent speed for fog.

 

[garyf]

Bob - I will assume that you are not implying that I run at a speed that reflects imprudent seamanship.

I didn't see that as a dig at you, Wesley. I do appreciate you sharing your research and perspectives!

I had a feeling I'd get some interesting responses in this thread - and, as usual, you guys didn't let me down! Much appreciated.

 

[hardee]

This is at a cruise speed of 10-11 knots, and shows both the horizon level and the cabin top and radome angles. Less that 6 or 7 degrees I think. I believe when I redid my radar strut, the angle wedge was 4 degrees.

I agree, when you really want the radar, FOG, (or dark - but I rarely do that), I will be at displacement speed = 3-4 knots, and I will be dialed in at 1 (or less) and 3 miles for the radar. I actually enjoy running in the fog, but hate going in the dark, although I have done both.

That photo of the 19 seems like it is not trimmed very well, maybe no trim tabs.

Harvey
SleepyC:moon

 

[thataway]

One consideration is that in dense fog one probably will use prudent seamanship, and be running at a much lower speed. .

Bob - I will assume that you are not implying that I run at a speed that reflects imprudent seamanship.

My choice of optimum dome tilt was based on actual pitch angle measurements throughout MY boat's speed range, which includes a prudent speed for fog.

PNW Wesley, I am not rendering any judgement on your seamanship. I have been involved with water and boating safety for over 70 years. I take every opportunity to promote marine safety.

I also gave my rational for the 3* down angle that I use. I have a fore and (as well as an athwartships level, as discussed in another current thread), to determine my boat's running attitude or angle at any point in time. Thus I know what the angle is when I am proceeding in limited visibility conditions, be it fog, smoke, heavy weather or darkness.

We have many new boaters who visit this site. As I am typing this there are 81 people viewing the forum. Only 4 of those are registered members. We have had as many as 755 viewers on line at one point in time.

I do run my radar at times when there is not limited visibility, even though I have been using radar for over 40 years and accrued many thousands of hours on various brands and types. When I really need it, I am in go slow mode.

Conventional wisdom is that mounting down angle is somewhere between 2* and 6*. The average is 4*. Since I run the boat at dead slow to full displacement speed in limited visibility I choose 3*

If you are going to be running your boat in limited visibility, where your best angle is 6*, then you made the correct choice. It is laudable that you looked at photos of various C Dorys..but what is important is what your boat does when at the speed you will most likely need radar.

As an aside, the use of AIS both receivers and transceivers has become the standard for marine safety in limited visibility conditions also. I only have a receiver, but if I was boating in an area with high traffic, and significant limited visibility, I would have an AIS transceiver.

 

[PNW_Wesley]

I do run my radar at times when there is not limited visibility......

If you are going to be running your boat in limited visibility, where your best angle is 6*, then you made the correct choice. It is laudable that you looked at photos of various C Dorys..but what is important is what your boat does when at the speed you will most likely need radar.

As an aside, the use of AIS both receivers and transceivers has become the standard for marine safety in limited visibility conditions also. I only have a receiver, but if I was boating in an area with high traffic, and significant limited visibility, I would have an AIS transceiver.

Hello Bob.

To quote Walter Brennan – “No brag, just fact.”

My 39 years as an avionics design engineer includes flight test, certification, and in-service support for X-band and C-band Doppler radar. In the early 80’s, when airline pilots were transitioning from analog radar to the Rockwell Collins digital radar on the Boeing 757/767, I flew in the jump seat for more than two hundred flights. My function on those flights was to coach the pilots on how to get the best performance from the radar. This involves varying controls such as range, gain, ground clutter suppression, and tilt. Small adjustments can go a long way toward increasing the pilot’s confidence in what the radar is displaying.

Prior to retiring, I was the Lead Engineer on a project to design a new digital autopilot for NASA’s WB-57 fleet in Houston. I was also the System Safety Engineer, and was responsible for analyzing the potential failure modes of the hardware and software, determining the effects and criticality of the failures, and determining methods to mitigate the severity of the failures.

When I stood before NASA’s review board, and proclaimed that the probability of certain catastrophic failure modes was in the 10 to the minus 9th range, I knew that very small numbers made a difference.

When it came to installing the dome on my boat, the engineer in me just couldn’t help following a detailed design process to ensure the best possible performance of the system.

My radar is on at all times while underway, regardless of the visibility. This allows me to continually assess what is on the display relative to what my eyes see outside. When I change a setting, I see the effect of that change within seconds. The net result is a very high confidence that when the fog rolls in, I have done the best I can to assure our safety.

To me, the greatest danger in dense fog is not the ships, which give a strong radar reflection. Most small fishing boats on the Columbia don’t have radar, but they do have a basic chart plotter. They zip along in low visibility, following their past tracks. Picking out a 14 foot fiberglass boat, low in the water, and doing 25 mph is a feat for any radar.

That boat can be coming from any direction. The vertical beam width implies that a signal return is likely to occur when the antenna is not level to the horizon. For optimum target discrimination, the beam should sweep as close to level as one can make it.

I enjoy knowing that my radar installation was done using empirical data. The purpose of studying other Dory’s was to validate my own testing data.

Stay safe out there!

 

[thataway]

PNW-Wesley,
I should have figured out that you are an aeronautical engineer! My father was an engineer, and I have a number of friends who worked for Douglas in Long Beach CA.

Good on keeping the radar on all of the time. Reading about the rescue on the Globe Vendee AWR, it was the human mark one eyeball which saw the strobe light, despite a radar reflector on the life raft and the AIS transmitter which was not doing its job!

Yes, the small craft are always an issue.--perhaps more worrying to me are the kayakers and SUP users , even in poor visibility. I would think that the aluminum boats would show up well, but with small fiberglass boats you will get the engine. bloc. One early morning off the coast of Mexico, I sent Marie forward with a spot light, because I was getting a constant blip but not on every sweep. Yep it was a panga, and we were picking up the engine block. This was with a 1982 Raytheon 4 KW state of the art at that time.

Absolutely, even today's best radars need to be specifically tuned--and not put on "auto" as so many boaters do--including experienced ones. Unfortunately when you are in heavy seas any minimal variation of the mounting angle looses any advantage.

What radar did you choose and why that specific radar? Tell us your experience with it.

Take care.

 

[hardee]

Wesley, Also +1 on using the radar all the time. Likewise here.

I have had occasion to find kayaks, at about 100 to 150 feet out, in 20 - 30 ft visability. Scary in that thjey were getting ready to cross Blackfish sound, in front of a tug with a barge tow and another tug with a log boom tow, both of which I had on AIS and radar.

Good on you to do that research.

Harvey
SleepyC :moon

 

[PNW_Wesley]

PNW-Wesley,
I should have figured out that you are an aeronautical engineer! My father was an engineer, and I have a number of friends who worked for Douglas in Long Beach CA.

What radar did you choose and why that specific radar? Tell us your experience with it.

I worked at Douglas LB from '79 to '82.

I chose the Garmin Fantom 18 for several reasons.

The Fantom’s 40-watt pulse means far less energy for the occupants to be exposed to, and the dome’s power consumption is considerably lower.

The component most likely to fail in older high-power radars is the magnetron, which generates the output pulses. The Fantom does not use a magnetron.

It has Doppler capability, which it uses to determine if a target is moving relative to other returns.

My first outing with this system was in February, on a 2-night cruise from Kalama to Astoria and Cathlamet.

Within the first 2 hours of using it, and still testing the various settings, it captured a target that really impressed me.

About 10 miles south of Cathlamet, there is a highway along the shore with cliffs on the north side of the highway. A cement tanker truck was heading west, about 0.3 miles off my starboard bow.

In a Doppler radar, the software looks at the amplitude of the instantaneous returns as they are received to determine if that return should be black, blue, yellow, or red on the display. It also measures the frequency of the received signal, which it uses to determine the motion of a target relative to other targets.

The software calculates the current closure point of your boat and a moving target. A moving target will be displayed as green or magenta, based on the potential for collision.

The signal returns from the rock cliffs were very strong, as shown by the solid red bar to the right of my heading line. The subtended angle of the truck was very small compared to the length of the cliffs.

When my radar picked up the truck, it was displayed in green. At that instant in time, the signal returns included those from the truck and from the cliffs behind it. The software was able to differentiate the frequency of each return, and found the moving truck. That is like picking out a candle in a forest fire.

I am happy with my system.

 

[thataway]

Thank you Wesley. Impressive photos!

Why did you choose the Garmin Fantom over the offerings by Furuno, Simrad (4G, Halo 20/24) or Lowrance (3G) or RayMarine Axiom Quantum 2 radars?

Also can you comment upon the choice of an 18" with a 5.2* horizontal beam vs the 24" with the 3.7* horizontal beam? Does the solid state negate the need for best discrimination? (One of the C Dory 25's had a 6' magnetron scanner, but it looked like a. helicopter)...

Another important feature of the solid state/digital radar vs the magnetron is that the solid state come on instantly, vs a usual 90 second warm up period for the magnetron.

Also the solid state/digital/broad band radars can "see" objets up to about 20' away (depending on location of scanner). The Magnetron units were blind to close up objects.

Comments about Long Beach in PM.