TOPIC: How to weigh a boat. - updates added.

Before I go any farther on this restoration of a 1964 OMC Evinrude Sport 16, I thought it would be a good idea to weigh the hull. I'd like to know just how much water is lurking in the foam beneath the floor.

The factory brochure says the bare hull weighs 810 pounds. I hooked the trailer up to my truck and toddled off to the local gravel company a half-mile away.

After waiting a while as the counter guy was on the phone, I relaxed and jawed with him a bit before asking about weighing the boat. Y'know, the normal stuff, "How's the yard guy working out?", Ain't the weather great?, etc. Then I told him my problem and made it clear I did not need a DOT approved weight slip ($20!). I just wanted to weigh the trailer with and without the boat. He said, "Sure, no problem. Run it on the scale".

He wrote down the gross weight of the trailer's main wheels (1,420#) and I drove back home. Parking in front of the garage, I hauled my old "Doctor's" scale out next to the trailer tongue. I didn't realize the tongue would be so heavy without an engine on the stern to counterbalance it. I had to use the jack to unhook the hitch, then I pulled it over to the scale.

I had put a handy wooden box on the scale to raise the platform up level with the truck hitch. It weighed 11#, so with that in mind, I weighed the hitch weight and subtracted 11. Wow, 221#! No wonder I couldn't lift it.

Then I drove the truck/boat out in my back field where both the dirt and the grass are nice and soft. I backed it up to a tree, looped a rope around the tree and tied a couple of bowlines onto the lifting eyes on the transom. Inching forward, it wasn't but a couple of feet and the trailer tilted, the boat rolled back and planted it's butt in the grass. A few more feet forward and she slid off the trailer just like a water launch.







I re-weighed the trailer tongue at 71# and drove back up to the gravel scale for the second weigh-in. The main trailer wheels pressed the scale at 540#.

So, here's the calculations:
Main wheels, Boat & trailer ........... 1420#
Tongue weight, Boat & trailer ......... 221#
Gross weight, Boat & trailer .......... 1641#

Main wheels, trailer only ............. 540#
Tongue weight, trailer only ........... 71#
Gross weight, trailer only ............ 611#

Boat & trailer ........................ 1641#
Minus trailer only .................... 611#
Boat weight ........................... 1030#
Factory specification weight .......... 810#
Water in bilge foam ................... 220#
Gallons of water @ 8#/gallon .......... 27.5

So, it looks like I will have one, fat, extra hidden passenger wherever I go. Since the payload for this boat is six passengers, motor, and gear, I don't see any need to spend six months or a year removing the floor, digging out the water-logged foam, and replacing the floor. 90% of the time it will carry only two people.

NOTE: DO NOT - REPEAT - KNOT use two bowlines to tie boat to tree. Bowlines must have some slack to untie. I had to use a come-along to back the boat up a few inches in order to untie the *&^%$ bowlines.

2ND. NOTE: My hand winch on the trailer would not budge to boat back onto the trailer. I just spent the last half hour removing the old hand winch and installing my Harbor Freight Tools electric winch. I'm taking a rum & diet cola break right now, but I'll be back out in the field in a bit. Gotta get that boat back into the tent garage for the night. There are rain showers predicted tomorrow and I don't want to get my brand-new seats and carpet all wet. Stay tuned.

FINAL NOTE:She's back on the trailer and put away for the night. Even the 2,000# straight pull, 5,000# marine use electric winch would not do the job all by itself. I had to put the truck in reverse and move it a couple of inches while my wife stood in the rear (well off to the side) with the winch remote. She would run the winch to take up the slack (and a bit more) then I'd back the truck up a tad more. Finally we got far enough the trailer began to tilt back down & things got immensely easier. The winch hauled it the rest of the way by itself.

The problem was that two of the roller stanchions extended 4" below the trailer and were plowing through the sod. Without that drag, it would have been easier, but likely still no picnic.

-Fini-

Well that turned into quite a project, eh Clark!? Now you KNOW what your boat and trailer weigh, anyway. (Without motor and gear.) From what I have read about others who have taken on this task, the published hull weights by the manufacturer are often under what is "real-life" readings. (Water in foam could certainly contribute to this, but I wonder if they weigh them before installing seats, hardware, carpet/flooring, etc..) Glad you got her back on the trailer without incident. Thanks for sharing your adventure and calculation formulas, love the "updates".

Mark ..........

I weighed it without the seats and carpeting - just a bare hull. Since I had everything out of it, I thought this would be the ideal time to get the weight. The seats showing in the pictures were just tossed back in to get them out of the garage.

Next time someone needs to do similar, on winching, take a pulley with a hook, pull the pulley axle out, thread in the wire, back together, and take the original bow hook, and double it back to the winch post. Cuts the effort in 1/2. I have the same setup on my 5000 LB 25 Bayliner. Walks it right on the trailer, out the water easy.

Y'know I thought about doing just that, but I didn't know if I had enough cable on the winch. I should have tried it - I have a snatch block that would work just perfect.

Hi Clark,

When i bought my G3 last November, the first thing I did was to drill a hole in the transom in the very bottom at the keel. Water started pouring out. I filled almost three 5 gallon buckets... which turned out to be a lot of extra weight (100+ lbs) for a 400 lb boat. Over that hole, I am mounting a brass garboard drain plug fitting... using just epoxy and screws.

www.iboats.com/Perko-Garboard-Drain-Plugs/dm/cart_id.421706819--session_id.600643159--view_id.21910

Then in the floor, i cut with a sabre-saw, a 4" hole (actually two) and installed deck access covers... which allows me to open them up when the boat is in storage so it can dry below the floor.

www.iboats.com/Boat-Deck-Plates/dm/view_id.373615

I ended up ripping up the entire floor and transom as part of my restoration, because the wood was rotted.

But, my point is that you can get that water out without tearing up the floor, and with the deck plates you can ventilate easily when the boat is in storage. Something relatively easy to think about. Your floor, stringers, and gas mileage will be much happier, getting rid of the 200 lbs of water. Just a suggestion.

Dean

Dean .........

That's interesting. The reason I say that is a few years ago, I was building a small dock (10' x 12') for my place. A friend had some old foam which he had saved when he cut up an old swim platform. He gave it to me for my dock.

I couldn't believe it when I picked it up. I thought for sure it would sink, it was so heavy! Needless to say, I didn't use it for my new dock! It sat around, under cover for several years before I finally took it to the dump. In all those years, it never dried out. It was just as heavy with water as ever.

Perhaps it was a different kind of foam than the stuff used in boats. The Evinrude literature on my boat says it is closed cell foam and shouldn't soak up water. But then it says that tri-hulls ride nice, too. Hah! Pass the Preparation "H"!

I would need to drill two holes in the lower transom, one on each side of center. There is a molded in depression in the floor, rear center, for a boat drain. There's even a bilge pump in the depression. Note: the soft parts in the transom which you can see will be replaced before hanging a motor.



But, I could put two drains in, one on each side of the well and then cut the topside access holes as you describe. It would be worth the try if it got rid of even a few gallons of water. As a pilot and a builder of an experimental plane, I well know the value of keeping things light. A plane that is a delight to fly with one pilot solo can easily become a slug with two people, baggage and full tanks.

Right now I'm under time constraints to get this puppy operable for a June fishing trip to Eastern Washington. I'm not going to do anything that doesn't directly contribute to that goal. I don't think I'm going to make it, though and I'll be fishing out of my 10' Hi-Laker again this year.

But when we return, the pressure's off. I'll likely try your solution. What's another hole or two in a 47 year-old transom that really should be replaced in toto anyway? Thanks for the real-world tip! I may owe you one if it works.

Yep, I totally understand... summer is right around the corner! I'm busting my chops to get my G3 done by June too! You know, you make a good point about the foam, I have seen what you describe about closed cell foam breaking down and absorbing water. The foam I removed from my bilge was partially waterlogged. I chose to reconstruct without any foam, but rather making the bilge an air-tight chamber that I can open up and let it breathe during the off season.

Where are you taking it to fish in Eastern WA? I did a fishing trip to Chelan last labor day, in my '59 Avalon... downriggers 200' deep and funny gear; not what I'm used to in Puget Sound and the Straits when hunting for salmon... didnt get a bite either! But let me say, I sure enjoyed the Eastern WA fresh water and weather a lot better than being chilly on the Sound.

Dean

Along with a group of retired Seattle Firefighters, we'll be trout fishing at Spectacle Lake near Tonasket, then heading for Lake Curlew near Republic for some Bass.