Trig Help

[Nauticus]

Originally Posted by TrentePieds

Good job, Spot, That's EXACTLY how you do it. :-)!

Now, I went for 50 feet under the bridge structure just to give a little extra heel to be on the safe side.

Now, to help out our OP, how would you suggest he induce a 40º heel on a 10 or 15 ton boat? I'll bet you my limit (35¢ Can.) that his boat doesn't have a running topping lift that's up to the job. And that his masthead sheaves for main and jib halyards don't swivel. :-)

TrentePieds

Line from top of mast with a weighted bag (usually water weight) pushed out from the beam at 90 deg from mast with spinnaker pole. Instant heel. Good luck!

You can find a video on YouTube of exactly that method.

[Jim Cate]

Originally Posted by Lodesman

Suggest the "substantial weight" is a barrel(s) full of water, so that when it hits the water, it stops pulling down.

Perhaps my term "substantial weight" is misleading here. The weight isn't meant to help with the heeling, it is to keep the line taught and would not be physically large. The drag from a barrel suspended from the masthead would make steering rather difficult IMO.

I had something like a lead salmon sinker (a kg or so) in mind.

Jim

[CruiseN]

45 degree angle
Lengths are 1
and 1over root 2.
1,2 we do kung ** from a practical side of equation; clearance.

Just another point of transit; even if to far.

60 over root 2 = 42.43 feet.

That is from pivot, 42 feet out, 42 feet up.

How long is low tide?

[belizesailor]

Originally Posted by CruiseN

45 degree angle

Lengths are 1

and 1over root 2.

1,2 we do kung ** from a practical side of equation; clearance.



Just another point of transit; even if to far.



60 over root 2 = 42.43 feet.



That is from pivot, 42 feet out, 42 feet up.



How long is low tide?

You make a lot more sense when you do math. [emoji6][emoji253]

[Lodesman]

Perhaps the OP would like to confirm whether 60' is air draft or stick height and freeboard needs to be added? What's the draft and beam too? Also is 54' the minimum clearance or the clearance at centre span?

I always remember Old Hands Always Help Old Airmen for sinθ=O/H; cosθ=A/H; tanθ=O/H where O is opposite side, A is adjacent, and H is hypotenuse.

In your theoretical triangle, air draft (60') is the hypotenuse and clearance (54') is the opposite side. 60/54= 0.9 use the inverse sin function on your handy scientific calculator to get θ of 64º - this is the angle from the water to the mast, so the complement (90-64= 26º) is the amount of heel.

To determine the length of the Adjacent side (the minimum width needed) use your calculator again to calculate cosθ = cos64º = 0.4358899 - remember this is A/H so multiply by H (60') to get 26.2'. Add half of your beam to that. Depending on your draft and how much you choose to heel you may want to do the same calculation with your draft as at a certain point your keel will extend past the beam.

[MicHughV]

I had to do something similar once....different circumstances......
I boomed the main boom out near perpendicular to the boat...and had the end of the boom supported by two halyards...and suitably braced fore and aft.
Then I hung a inflatable dink from the end of the boom, so that it was clear of the water, by several feet.
Then I laboriously filled the dink with water..this took some time.....but it produced sufficient heel to to the job for me...

one more thing....with the boat heeled over so far, your primary propulsion, may have some issues...so you might want to consider having a " push-boat handy"

[Time2Go]

OP Here
Thanx for all your responses
Boat is keel stepped Irwin 44
Stick hight is from waterline
(57 plus 3’ Antenna)
We do indeed plan to use a plum line from mast
to verify that we will clear
The plan is to use water filled barrels on the deck
to induce heel.
We also have stout topping lifts for both the
boom and spinnaker pole if needed
Not going to do this till sometime in July
and will post some pictures then.
Thanx again for all your responses
Cheers
Neil

[MicHughV]

the antenna can always be removed...easy enuff....save you 3'...

[Lodesman]

It was brought to my attention that I made a typo above - it should read tanθ=O/A. I also noticed that I flipped around the O and H - it should be 54/60=0.9.

So with actual data 54/57=.9474 arcsin= 71.3º so 18.7º heel at least.
Cos71.3=0.32 x 57= 18.2 + (1/2 beam) 13.3/2= about 25' minimum width.
Assuming you remove the antenna.

[Spot]

Originally Posted by Lodesman

It was brought to my attention that I made a typo above - it should read tanθ=O/A. I also noticed that I flipped around the O and H - it should be 54/60=0.9.

So with actual data 54/57=.9474 arcsin= 71.3º so 18.7º heel at least.
Cos71.3=0.32 x 57= 18.2 + (1/2 beam) 13.3/2= about 25' minimum width.
Assuming you remove the antenna.

The trig of the Lodesman is working mighy powerful on CF :

[MicHughV]

being purely semantic here, but as the boat heels over, the center of buoyancy of the boat changes, and this has the result of pushing the point of mast rotation upwards.

This can be calculated, if a variety of parameters are known....but I would allow for a minimum of 12" upwards movement, meaning to say, as the boat is being heeled over, the point of rotation of the mast will go up....so the above graphic should be revised.

[Montanan]

Be VERY cautious applying that massive amount of weight on your deck or cabin top, boats are not designed to carry such point loads. Truly crushing load.

And as the many videos depict the barrels need to be braced so as to not shift from their support structures as they do tend to roll or tip over when placed at a high angle. If they move then all hell breaks loses as will the induced angle.
They will destroy you stanchions if the life lines or rails if such end up bracing the load.

Seemingly easier and safer to just lower the mast.

Good luck.

[Spot]

Originally Posted by MicHughV

being purely semantic here, but as the boat heels over, the center of buoyancy of the boat changes, and this has the result of pushing the point of mast rotation upwards.

This can be calculated, if a variety of parameters are known....but I would allow for a minimum of 12" upwards movement, meaning to say, as the boat is being heeled over, the point of rotation of the mast will go up....so the above graphic should be revised.

Since I am not a naval architect or draughtsman, the pictures (past, present, and future) are for entertainment and illustrative purposes only, to show that the trig seems to be working. No warranty expressed or implied...

[El Pinguino]

Originally Posted by sail sfbay

I did not have a protractor.........tossed it when I retired......but using the formula in this link came up 57.54 degrees based on a = 54 ft, b= 34.5 ft, c= 64 ft

https://www.omnicalculator.com/math/triangle-angle

No protractor? Just use the compass rose on one of your paper charts.

[CruiseN]

Originally Posted by Spot

Since I am not a naval architect or draughtsman, the pictures (past, present, and future) are for entertainment and illustrative purposes only, to show that the trig seems to be working. No warranty expressed or implied...

They look beautiful.
You an artist or something?
Eye herd sailing an art.



At which tide is clearance?
We get 2 metre tides down this way, I don't know where clearance is measured. Low Mark? 2 metre mark?

I'd check to confirm that.

If from a higher mark then you might be getting pretty close to zero heel with no antenna but no room for error and not an often practiced skill.

Just pros and cons. Not advising such.
I'd want error margins too.