Removing Seats from Aluminum Jon - Strength Issues

[LarryJ]

Are there any experts out there that can answer a question about problems with modifying an aluminum jon. The manufaturer of the jon was very vaugh in their reply. I've got a 15ft Alumacraft Mod-V welded jon (AW1546DD tunnel). The back seat takes up way too much room, so I'd like to cut out the center portion of the seat leaving only a narrow portion against the sides. The manufacturer said the boat would lose a little "strength" (and floatation under the seat) if I did this, but they couldn't explain what they meant by strength. If the center portion of the seat is removed, how is the boat affected? I understand that if another boat rammed me on the side that the boat may not take the blow the same as if the seat were there, but other than that, Im at a loss. Thanks.

[kmorin]

LJ, the aft deck/platform is too critical to remove in this design according to the very little visible details of a plan view diagram on the web.

That box stablizes the warped bottom, the sides and the transom/motor mount all at once by creating a thwart (inverted box) beam.

manufactured boats are engineered to the final percent of metal versus shape versus costs. I doubt they've left you room to remove ANY parts and retain the structural integrity of the boat.

As you add people, the boat will draw more water which will push in on the sides as the boat sits lower and this box is all that is provided to resist the sides' inward lean in the stern 1/3 of the boat.

The tunnel or warp in the bottom looks fully supported by this boxed area - so if you remove the area of the vertical sides of the box across this part of the hull, it will very likely begin to flex and crack.

I can't see the details clearly on the web provided info, but for certain if you cut anything out of their boat you're voiding whatever back-up they offer and you're discussing cutting out one of only two main structural tranverse elements of that boat.

Don't cut out the deck platform the boat will "work" in diagonally, may allow the tunnel to flex and the sides to transom gussets will be loaded much higher that planned and will fail.

I'm not an expert in these boats, but have "repaired" lots of freshwater sleds.

Cheers,
kmorin

[LarryJ]

KMorin,

Thanks for your reply. That was much more of a technical explaination than the manufacturer could provide. The manufacturer also stated that their "waterfowler" series boat of the same size doesn't have a rear seat as vertical support (as you say) because the boat "has an extra rib that ties in down the center of the hull". I can't picture this extra rib, but I wonder if the rear seat could be removed if this extra rib were added.

Larry