How to determine if a used hull is straight and true?

[MarshGator]

What’s the best method to determine if a used hull is straight and true? Looking at an 18’ Aluminum hull with engine stand, cage, and some of the rigging.

I believe the hull side slid into something and bent (compressed) the u shape t-bars that run from side to side. Two T-bar side supports that run across the hull are unbolted and not connected to one side. On the trailer the hull looks straight, but I intend to get the hull flat on the ground to see if it still looks straight. If the hull looks good, I believe it would only require two new t-bars supports to replace the bent (compressed) ones.

Any thoughts or comments?

 

[daharh]

for squareness measure corner to corner both ways should be the same or it is out of square

 

[Rich Andrews]

find the old owner, get his input.

 

[SwampMatt]

ccasion5:

 

[MarshGator]

Boat was out on seismic work. The owner (not driver) thinks the boat was slid into something. Also, engine stand and cage are set-up for belt drive.

 

[Gbenzx]

Gator,

If I can detect that any boat has took a bad lick I will go the other way.

My nephew looked at a Jon abt two years ago thought it looked funny he said sitting on a little trailer. The man told him it had a couple licks but was ok. When he started to walk away the man asked him would he give anything for it & he replied $150 & bought it.

It has never been right. Anytime he punches the kicker it turns right. He thinks it may have departed from the trailer on the highway sometime.

You cam sqwat down & look from front to back lining up the bow with the transom & detect the horizontal difference &/or use a carpenter level.

Don't know howfar you are from MarshmasterPat but maybe he'll see your thread.

Just my 2 puny pennies

Gben

 

[marshmaster pat]

There are some good seismic hulls out there and sometimes have a fairly good price on them, but could have lots of hours over rough ground. So beware of those old seismic boats. They can be good, but they run them in the swamp, bounce off cypress knees and tree trunks. Run them like crazy in the marshes, go in a straight line, crossing anything and everything in their path. If you don't or can't go, you load her up and head home.

See if the transom is square like Daharh said. Also see if you can make the t-bar fit back into place. You can measure the T-bar from the edge on the gunnel to the center rib, it should be the same distance on either side as well. Look for hull rewelds along the ribs and T-bars. Setting it on level ground will sometimes help make twisted hulls easier to spot.

With a belt drive set up you will notice some torque from the motor and prop rotation being the same direction. But it is not bad in a 18 footer.

Good Luck

 

[MarshGator]

Thanks for the info Marshmaster Pat. I can almost pull the t-bars back in place by hand. Looks and feels like two of the u-shaped t-bars have been compressed and the hull seems fairly straight on the trailer until I pull the two t-bars back into place. My thought is to replace the two compressed u-shaped t-bars. What do you think?

 

[cntry141iq]

Marshgator: If this is your first boat I wouldn't be especially worried about the hull. I would concentrate on the engine stand, seat stand & cage. The next most important is the engine. You can always put that stuff in a new hull later on. I have found that most people will put a few dents in the hull right away while learning to drive. Fiberglass breaks but you can hammer out the big dents in alum.

The facts are in my opinion your first hull or two are considered sacrificial lambs. Moodfood I know you will read this also and you did good but the wide water we were running was very easy except for the waves on the way back. When a newbie gets on a skinny trail with real obstacles like trees and stumps on the sides and the speed gets picked up a couple of notches bumps are gonna occur. Basketcase your boat has so far kept you in safer locations where all you had to worry about was sinking it. When all else gets right with your boat then your airboating exhillaration will increase greatly. I still hit stuff sometimes I have a big dent in my bottom from a stump that was in the grass and I was the midlle boat running three wide at night at 40 miles an hour or so and no where to go.

If the hull is reasonably straight and the price is reasonable go for it. When you get done with it it will probably be just what someone else is looking for at that time also. HAVE FUN

 

[Gbenzx]

Gator,

First I cannot advise you simply because I haven't sat on any Airboat sense 1955 I believe it was. So just from our use of motorboats over the years.
Next thing you are hearing from some of the very experienced Airboat folks that I listen to in our own effort to arrive at the right conclusions. In no way do I intend to disagree with any of them.(except Matt

But if I may,

On Airboat Trader in the 5-10,000 range there is a Capt Doug House with what appears tobe some pretty good 18ft Alum Airboats & Hulls at fairly good prices.

Now I don't know this man from adam but being a tour boat operator one would thimk he probly keeps his boats upto snuff.

The other thing was, have they yet said why this Airboat became a Hull instead of an Airboat? See if theyll take say $250

That's all, my last 2 pennies,

Gben

Also one at traderonline, Eustis fl