Alcanboats Forum

I can't find a transom plate that tells me weight/passenger capacity on my Alcan 370. Any of you out there have one or know what the limit is for our boats?
After googling around, I found a rough guideline... length (37) x beam (12) ÷ 15 = 29.6
Does this make sense to you?

Well, let's see. 30 x an average weight of 170(?) lbs = 5100 lbs of people.

Fresh water weighs about 62 lbs/cubic foot and your 37' has a 'footprint' of about 35 x 12 = 420 sqft.

5100 divided by 62 = 82.25 cuft of water that would be displaced.

82.25 cuft divided by 420 = .20 (L x W x H = cubic measure) We knew Length & Width and needed Height.

35 x 12 x .20(of a foot or 2.4 inches) = 82.25 cuft of extra water displaced. 82.25 x 62 lbs(weight cuft of water) = 5099 lbs of water. That's close enough to our 5100 lbs of people.

So 30 people would only lower the boat 2 and a half inches. This assumes they are evenly distributed and don't move around much.

If everyone wants to go up on the roof, or all on one side, you're going to have problems.


Jay

The previous owner of our boat twice a season would travel down the river with about 30 people everyone I talked to said they had a good time and no troubles so I think that are boats are OK with that at least but I also do not have a transom plate. Hope this helps

The "transom plate" on an Alwest is the electrical ground plate, more or less on the center line of the transom just under the deck. It should have the hull number above the row of ground screws, but since the wires are usually routed up, they often obscure the number. (There was no further info required in the late 60s/early 70s.)

A good calculation by Jay, but as he notes, this represents an evenly distributed loat that stays still ! I have had about 16 people on board Catherine Ann (an Alwest 370) . . . . and everything is fine until everybody goes to one side (to help with docking) . . . . then things get "interesting"

I also often wonder about the wooden structure supporting the cabin roof . . . . these are just 2x2s on about 16" centres. I have had 10 or more people lounging about up there (at anchor) and seriously wondered if they might all be about to end up in the aft cabin You "Alcan" guys don't have this to worry about . . . .

Just another piece of anecdotal evidence, but I remember reading somewhere that they were certified to carry 23 people. I'll have to dig through my stuff to see if this is authoritative or just bad memory.