[deadheaddave]

Hello guys, I am just getting into owning/modifying boats, and my current (and first) project is a fairly simple one.

I have a 16' aluminum v-hull with no branding on the hull, I think it may be an older aluma-craft, although I am not entirely sure. the mods I am making are primarily cosmetic, and the only thing I would like to do that is or may be structural is my sticky wicket. This boat has a space behind the rear bench that I am planning on building a platform with raised seat over. Inside will be a removable gas tank, elevated storage for two batteries, and fuses for all the electrrical. On the front, (there is already an existing locker between the point of the bow and the front bench seat) I would like to build a casting platform with built in live well, cooler, and utility locker.

Now, comes the part I am uncertain about. There is a bench seat with foam under it in the middle of the boat. It has steel strapping material that kicks up to the top of the side rail, and a 2 x 12 for bench material. I am wondering just how structural this is. At the floor around the edge, it has been rolled in two directions which gives me a nice little shelf for the decking material, and I assume adds stregnth to this part of the boat, (are those the gunnels?)

What I would like to do is remove this middle seat, and build a low deck from about 1/3 to 7/8 of the boat with benchs down both sides of the boat for use as a rod locker on one side, and storage on the other.

I was thinking that if I dropped the 2 x 12 down to the floor, and built angled braces from the rail to the newly positioned plank, and then built the side bench/box to hide it that I would retain any of the structure that was originally provided, and open that spot up to be a walk through from bow to stern.

oh, and it's a stern drive motor, so there is no panel or sterring console to worry about.

So what do ya think? can I do this?????

thanks in advance for the help/input.

Dave

[ccarver]

pictures would be nice... ... i own a 14' aluminum boat ... it had three main benchs one in the back, middle, and front.... i didnt like it... so i took a sledge hammer to them... put a 4x8 sheet of plywood down for a flat bottom and called it good! now i can walk freely around my boat!

[cprince]

Originally Posted by ccarver

pictures would be nice... ... i own a 14' aluminum boat ... it had three main benchs one in the back, middle, and front.... i didnt like it... so i took a sledge hammer to them... put a 4x8 sheet of plywood down for a flat bottom and called it good! now i can walk freely around my boat!

Depending on your model, from what I understand, most smaller aluminum boats get their structural integrity from the main seam down the middle length of the craft (Keel I believe) and from the benches. If you hope to survive at WOT and not fold your boat in half doing it... you might want to keep your benches... unless you have some other plan to replace the rigidity that is lost from that bench.

[ccarver]

good point.. im still altering my plans ... its not a deep v boat.. its liike pretty much flat in the back.. and a little v in the front... crazy design... idk what im gonna do yet... i might keep the back bench and front bench.. and leave the middle wide open or somthing.. idk yet i have all school year to figure it out

[deadheaddave]

Well, I guess I fell victim to the old too much info problem,
that was my main question,

Do you nautical engineer types think that a 2x12 stringer across the width of the boat with wood knee braces kicked up to the gunnels would provide sufficient strgnth to replace a 2x12 horizontal brace that currently runs from side to side about 1 foot below the gunnels?

?????

[mthieme]

That will be fine.
I assume you're not hanging a 350 Verado on the back.

[deadheaddave]

Originally Posted by mthieme

That will be fine.
I assume you're not hanging a 350 Verado on the back.

No, this is a lake boat in colorado, so the wind can get a little rough at times, but generally not too bad. It has a 15 hp gamefisher 2 stroke, and 36 lb thrust minn-kota, both stern mounted. The angled braces would terminate at the floor to a 2x12 running the width of the boat, and at the top just short of the gunnels wherer the angle seat that the old bench decking (also 2x12) is attached. This way I could build a full legnth bench seat from bow to stern with a single door for a rod locker, (i'm thinking I should be able to get as many as eight rods, up to ten feet long in it) and on the other side just some dry storage for snacks, and vest and such. If I decide to undertake this project I will post pics as it goes, on paper it has great potential, and since it is a bare bones boat right now, the change should be dramatic......

I think I am gonna do it unless someone speaks up soon to scream don't......

Dave

[deadheaddave]

bump...

[AZMinyard]

Any chance we can see some pictures? It's kind of hard to say one way or another without seeing what you are working with . . .

You might try measuring the width of the boat at each seat, removing the seat in such a manner as to be able to replace them and filling the boat to the water line with water. Measure again, if the boat has flexed to any noticable degree the seats are most likely structural and will need to be replaced or alternate support added.

It's your boat . . .

[reelfishin]

I had a 16' Mirrocraft lakemaster that had three bolted in bench seats with the rear one being attached to two large rear corner boxes that also held flotation. Both benches were aluminum shells with a 3/4" wood inner plank for strength, I played around with a few ideas about losing one of the benches but the result was too much movement in the gunwales. The seats were what held the sides of the boat rigid, without them, the sides were way too weak. I replaced the rotted wood inner plank, reglued the foam block in place and reattached the seat. If I were to make a sold deck, it would have to be over top of the seats. I didn't like the idea of having such a high center of gravity so I left it alone. I ended up finding an open floor style boat soon after anyhow and sold the bench style boat.

Even on the open floor style, the side rod boxes and console provided support for the gunwales. Removing any structure would require adding something back in to support the sides.

[mthieme]

Usually the back seat is not far from the transom so as to be able to operate a tiller. If he adds a rib, throws plywood on top and supports the plywood on the edges, say with angle, he should keep the rigidity.

[reelfishin]

It's pretty much a judgement call on each hull design. I've had a few that could withstand a lot of modification without any serious additional support being added. My Mirrocraft had a horseshoe shaped rear seating area, both rear corners were boxed in plus it had an integral splash tray. The transom strength wasn't an issue so long as the splash tray wasn't removed. The two corner boxes looked more like seating area for the driver with a tiller motor.
On mine, it was the first or rear most bench that was sort of redundant, it was more or less just an obstacle to step over to get into the driving position.

The middle seat was very important since it also held four diagonal braces from the top of the seat bench to the gunwale rail. The boat had a narrow gunwale edge, so without some serious support, the sides were no much more than a single panel of sheet metal with about a 1" strip on top.
It was a good boat for what it was, but not super sturdy overall. I liked my 1987 Grumman much better, that had integral tubing style gunwale rails and needed no additional support on the sides to be rigid. WIth the cost of fuel these days and my going back to smaller boats, I wish I still owned any of the three Grumman boats I had back then.

[BF]

I personally wouldn't do it. I have 2 16' aluminum utility boats like you describe. One has 3 full width benches and a bow seat, the other has a split rear seat, 2 full width benches and the bow seat. The one with 3 benches is a much more sturdy boat. The one I have with a split pulpit is very dependent on the rear most bench to keep the floor rigid. Even still, there is flexing of the floor when in chop that eventually causes the rivets holding the base of the rear bench to work loose.

I think removing the 2nd from the rear bench would leave a big chunk of floor unsupported and greatly reduce the overall rigidity of the boat. You mentioned dropping the 2x12, but is it going to be attached somehow to the bottom of the boat for the whole width of the boat? The strength of the benches comes from having the 2 bulkheads attached to the bottom of the boat and joined rigidly at the top by the seating wood. I think the box that is formed is much more important than the little braces that just brace the sides.

Dropping the height of the bench by 1/2 or so might make it more liveable, but still maintain rigidity (?).

[Grits]

Are you sure you boat is not an old Arkansas Traveler?

I would be careful taking the seat out. In my opinion. if you do, you will need to stiffen it somehow. Keep in mind, you are also losing a lot of your floatation.

Grits

[Calhere]

Well simply put here are some quick ideas, firstly use marine grade plywood otherwise go ahead and hang it up regular ply wood is not meant for outdoor environments, secondly yes the plywood running the length of the boat would actually make it a tad bit stronger not to much. as far as putting a live well, i do not know.