Overloaded? Correct waterline?

[pcmm]

Originally Posted by Idaho

If this is not too much trouble, I would appreciate your help as you suggest. At least it gives a reasonable starting point, even if yours is a bit bow heavy. Thank you.

Alright, back from the boat, and my exhaust is approx 4 inches from the waterline to the bottom lip. I have a 3 inch exhaust as opposed to the stock 2 inch. Ball park the bottom of the exhaust port on a Morgan OI 415 (mine is a 1978 vintage) should be roughly 4-5 inches above the waterline at rest.

[Idaho]

Thank you, PCMM!

Cheers!

[ikebartlett]

Find a straight pole or 2x4 thats wider than your boat, tie lines on both ends, once tied mark the lines at the normal draft and up every inch for 6 inches . Secure a couple weights at the mid point of the pole. Get a couple friends over for an hour and starting at the bow waterline keep moving the pole back. Take measurements every foot until you get to your deepest point. Voilà, now you know your actual draft. If it’s well and truely overloaded then the next time you’re out of the water, raise the barrier coat and boot stripe or remove some weight. P.S. Having at least one person in the water will help a lot.

[Nicholson58]

Originally Posted by tkeithlu

Your maximum draft is 4.16 feet. Given the shape of your keel that should be fairly easy to measure, assuming the boat is out of the water. You could compare that measurement with the point at which the boat is 34.00 feet at the waterline. If you have access to a crane with the ability of weigh, your dead weight of 27,000 pounds could also be a point to measure and compare.

I suspect that the usual answer is that ordinary spare parts, clothing, and food don't make much difference. Order of magnitude one inch of draft on your boat would be about 1,100 pounds of load. That's a lot of luggage.

Water and fuel can add up if you have big tanks. Ours total #7000.

Before haul out use tape or a marker to note where the real water line is.

Use the known draft to measure what the story is. Make sure you are leveled well including vertical, plumb. In the end, the WL is what it is. If the PO moved and botched it then making it right is worthwhile.

If you need to repaint, consider renting a laser level. Set the laser at the intended water line height. Shoot the length of the boat and use tape to mark.

We reset ours water stripe a few years ago in Trinidad. I didn’t like the scum line half into the paint stripe so we raised it 4 inches. For us, full tanks and inventory are around #10,000. Anchors and chains, ground tackle, dinghy, 2 outboards, alone are #2500. Typically, extras like this, large batteries, generator etc are not in the manufacturing total.

[Cynara]

Our boat had the waterline molded into the hull when it was laid up

[drdoyle]

Fill it up with fuel, water and supplies. Check to make sure your bilge pump drains are at least 12 inches above the water line and have reverse check valves to prevent back siphoning. Make sure the engine and generator exhaust systems have risers at least 12 inches above the waterline. All though hulls that back flow to engines and systems that need to keep the water out need proper vented loops. Once you are floating at full load mark the waterline and measure it down from deck reference points. The next time you haul out paint the new line and add a boot stripe above that.

[NPCampbell]

I would ballpark that it takes around 2000 additional pounds to lower your boat 1 inch.

Estimating the area of the cross section of your boat at the waterline to be LWL x beam would yield 13 ft x 34 ft = 442 ft^2. 1 inch of displacement for that amount of area would be 442 ft^2 / 12 = 37 ft^3. The weight of salt water for that amount of displacement is 37 ft^3 x 64 lb/ft^3 = 2368 pounds.

[Bowdrie]

Originally Posted by NPCampbell

I would ballpark that it takes around 2000 additional pounds to lower your boat 1 inch.
Estimating the area of the cross section of your boat at the waterline to be LWL x beam would yield 13 ft x 34 ft = 442 ft^2.

Well, it would be if the hull was a rectangular barge with those dimensions, but actual waterplane area will be a lot less.
Whether fine or full ended, for a typical sailboat the waterplane area generally ends-up being somewhere in the 55>65% range, more modern shaped hulls can go up a bit.
Of course, bluff bowed/square sterned powerboats are higher.
The pounds-per-inch immersion figures are also not linear, because of the flare in the sections and WL increase as the hull is pushed down.
With the boat sitting quietly and parallel in a slip it's possible to use a tape measure to get offsets at regular intervals along the WL and determine the water plane area with a fair degree of accuracy.

[jalmberg]

You could try some destructive testing and chip off enough paint to uncover the original waterline. That might be difficult to do if it's underwater (which it sounds like it is!)

We just crossed the Atlantic this year and before we left, we took a whole day and went through the whole boat and got rid of everything we didn't REALLY need. We try to do that every year, but we still found about 500 lbs of junk. It makes a difference.

[NPCampbell]

Originally Posted by Bowdrie

Well, it would be if the hull was a rectangular barge with those dimensions, but actual waterplane area will be a lot less.
Whether fine or full ended, for a typical sailboat the waterplane area generally ends-up being somewhere in the 55>65% range, more modern shaped hulls can go up a bit.
Of course, bluff bowed/square sterned powerboats are higher.
The pounds-per-inch immersion figures are also not linear, because of the flare in the sections and WL increase as the hull is pushed down.
With the boat sitting quietly and parallel in a slip it's possible to use a tape measure to get offsets at regular intervals along the WL and determine the water plane area with a fair degree of accuracy.

Correct. I knew I shouldn't have skipped steps ... I lowered my "guesstimate" of 1 inch of displacement = 2000 lbs instead of 1 inch = 2368 lbs due to the following:

Around 70% of that boat's hull appears to be roughly square at the waterline so I rounded the beam down to handle that (13.8 down to 13). The front 30% is roughly triangular. Due to this I reduced the area of the front 30% by 1/2 to 15%. If a square displacement weighs 2368 pounds then a 70% square + 30% triangular displacement = 2368 x (70% + 15%) = 2021 pounds so I ballparked 1 inch of displacement as 2000 pounds instead of 2368. This should hopefully get you within 10% or so of reality.

[MJH]

Originally Posted by Idaho

I have been trying to locate info on where the proper and correct waterline should be on my boat. I looked at the original owners manual, and searched the Internet, no luck.

Its a 1982 Morgan 416, Out Island ketch.

Does anyone know how to find the proper waterline? I want to make sure the boat has not been overloaded with spares and stores.

Over the years its possible the paint lines have been changed, so I guess the best indicator would be the exhaust thruhull, when the boat is balanced out as level.

How high above the water should the exhaust be? Is there a specific Morgan forum somewhere, to ask this question? Any ideas on where I might find this info?

I don't really care where the original waterline was on my 1979 monohull, particularly since the hull was painted by the previous owners. My concern is more with what it is now for cruising, and I raised it. What I don't want is a waterline that gets badly fouled between bottom paintings.

If you want to know if you are "overloaded" take a photo of the Marine Travelift operator's control device screen when the boat is being hauled...that's what I do. If you then subtract your fuel and water levels you'll get a good idea if you are overloaded and by how much.

My previous boat was a San Juan 28 with a manufactured 50% Ballast to Displacement ratio. For my trip to Alaska I meticulously weighed everything on my bathroom scale that I was putting aboard the boat for the trip and took a photo of the boat fully loaded (709.5 lbs)...she was definitely overloaded but recovered somewhat as I ate and drank my way there and back.

[Cynara]

We just painted over the waterline. So what you saw above the water was bottom paint. Elimatated all that unnecessary work

[Shaneesprit]

Originally Posted by Idaho

I have been trying to locate info on where the proper and correct waterline should be on my boat. I looked at the original owners manual, and searched the Internet, no luck.

Its a 1982 Morgan 416, Out Island ketch.

Does anyone know how to find the proper waterline? I want to make sure the boat has not been overloaded with spares and stores.

Over the years its possible the paint lines have been changed, so I guess the best indicator would be the exhaust thruhull, when the boat is balanced out as level.

How high above the water should the exhaust be? Is there a specific Morgan forum somewhere, to ask this question? Any ideas on where I might find this info?

If you really want to measure it while in the water (not everyone hauls out yearly)
Then I think a metal bar about the width of the boat with measurements equally marked on a rope well 2 ropes 1 each side , marked at where you expect the water line to be, then over the stern pull forward to the middle and with the ropes at equal lengths you have the draft.

[gillesgiv]

I had a Hunter 456 center cockpit. Heavy boat. I weighted it at 33,000 pounds with empty tanks and the book says dry weight supposed to be 26,000.
I measured the draft from where the water was and it was 7 feet. The specs said 6’6´´. The specs were wrong. I never understood why.

[jtsailjt]

Originally Posted by gillesgiv

I had a Hunter 456 center cockpit. Heavy boat. I weighted it at 33,000 pounds with empty tanks and the book says dry weight supposed to be 26,000.

I measured the draft from where the water was and it was 7 feet. The specs said 6’6´´. The specs were wrong. I never understood why.

Added equipment and personal items and full tanks add to weight but I’ve found that it’s pretty common for the advertised weight of a boat to be more a reflection of the naval architects intention than how it was actually built by the manufacturer.