14' Starcraft Modifications

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WTL

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I am in the process of totally modding my starcraft into a bass boat that meets my needs. I love this forum, have been lurkin for a while and recently I ran into a safety related issue that I wanted to bounce off you people.

I removed the bench seats first thing cause I wanted it to be more open. I want to be clear that adding them back is not an option. I have a 28 horse Johnson pushing this.


Theres ribbing all along, but no stringers as I understand it. When I took it to the lake today, it porpoised and there was a funny feeling in the little console when it did it. I hope I wasn't feeling the hull flex.



I am using the middle deck like a big bench seat, it is lower than the seats originally were but I am reusing the aluminum angles that went with the seats to add strentgh to the side.

The problem is I took it out the other day and it leaked some along the seams of each side. A little silicone made it better, but I don't want to be looking at a structural failure in the future.

Do you guys reinforce the boats longitudally, or is the aluminum hull normally strong enough?
 

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Thanks. Glad to be posting here now.


Only took her out before with the TM on, I didn't have the outboard yet. I'm sure the benches added some support.

The middle deck is now trying to serve as a bench, so I am less worried about the boat caving in on the sides. And I still need to get the middle deck in there more solid. But I was just sorta freaked out by that bumping feeling the console had (it could have just been loose, but it only moved when it porpoised hard). I started to think about the structure length wise. Didn't know if yall address that when you do mods. I could also in theory be overpowered, and the outboard is on a 5 inch setback jack plate. Can a boat like this really break in two titanic style, or is that a wives tale?
 
WTL said:
Can a boat like this really break in two titanic style, or is that a wives tale?

That's an old wive's tale. A boat like yours will just fold in half front to back like a sandwich trapping you inside while it sinks. :lol:
 
flounderhead59 said:
WTL said:
Can a boat like this really break in two titanic style, or is that a wives tale?

That's an old wive's tale. A boat like yours will just fold in half front to back like a sandwich trapping you inside while it sinks. :lol:

Yes, what Andy said above is possible.

Fore and aft stringer support in the bottom may help, but there are the still the sides to contend with. You know the throw-away aluminum [tin foil] pans you can get at the grocery store? Ever took one and picked it up by the sides when it had food in it, but the sides were flimsy and still wanted to twist? I believe that's what your boat may be doing (without actually seeing it in person); not positive, but it's highly possible.
 
I think more than anything the jackplate is just screwing up the balance a little, making it stern heavy and prone to porpoising. It seems to have moved the center of gravity back. It only acted funny when it popped up and down.

OK, so what should I do to be on the safe side. Remember the benches arent going back in, but the floors are serving part of that purpose anyways. Does that 2 part marine foam add enough rigidity or should I look at running a length or 2 of angle up the lenght of the boat (and I suppose attatch more angle supports to the floor up the sides)?


What do yall normally do? I know for a fact I'm not the only one here who has removed bench seats.
 
Waterwings,
not at all, I'm not touchy feely. I just want to be on the safe side too. This thing is going out on lake kissimmee with all its swells at some point, it can make the river fine I'm sure...but its gonna be taking a beating and I want it solid.

Back to the jack plate thing, the way its planing is a little off. Like the stern is just a little deep to be said to be planing, but this is at 15 mph or so and its roughly balanced on top of the water, just not like other boats I've been in.
 
A jack plate will make your stern sit lower. There is "another" site that actually promotes the use of a basketball, jammed in the jack plate and inflated to compensate for it. I refuse to mention that site here but we know who it is. coughBBCcough
 
I'm certainly not an expert concerning jackplates, but that could be one of the problems causing the porpoising. Do you have electric trim on the motor, and able to adjust it (in/out)? If so, try trimming it in or out some and see if that helps. The Tracker I used to have would porpoise (at higher speed) if I didn't have the motor trimmed properly. As far as the foam, I don't believe it would add any real structural rigidity to the hull. There will be some more members adding some thoughts to this as soon as they see the post.
 
I missed the basketball thing. Say what now?

Its a homeade jackplate, completely manual. I think I might fiddle with the tilt, its in the 2nd hole right now, might move it the first although I've never seen an outboard run right in the first. Could also trim it up just a hair, its a longshaft motor on a 15" transom hence the jack plate and modded transom.
 
Oh, some of those guys that have more money than common sense (or deep pocket sponsors) buy those $45,000.00 bass boats with the 300hp motors put on big 'ol 10" jack plates and complain the boat sits low in the back end. One of the "fix-alls" is a basketball shoved in the jack plate opening. Supposedly the buoyancy of the basketball compensates for the motor being set back that far. Personally I think it might help some... however the entire basketball would have to be under the water line AND I don't think just one basketball has enough buoyancy to do the job.
 
I just don't see how that would make a difference if you are on the plane, the b ball should be out of the water.

I'm going to adjust it some today and tommorow and see if we can't strike the right balance.
 
The basketball thing is only designed for when you are coming off plane or are stopped. You are correct, on plane the b-ball will be out of the water
 
The guy that does the book on modifying a jon boat to bass boat says that by putting paneling down the sides of the boat on the ribs you add the support that the benches gave the boat. I guess it would be like building a torsion box. He says to use as long of plywood for the panels as you can get(mostly 8') and screw(or pop rivet) that to the ribs. He also says to put the foam from the benches under the side panels so you don't lose flotation.
Good luck,
Mary
 
bluegillfisher said:
The guy that does the book on modifying a jon boat to bass boat says that by putting paneling down the sides of the boat on the ribs you add the support that the benches gave the boat. I guess it would be like building a torsion box. He says to use as long of plywood for the panels as you can get(mostly 8') and screw(or pop rivet) that to the ribs. He also says to put the foam from the benches under the side panels so you don't lose flotation.
Good luck,
Mary


That does make perfect sense! :D
 
Your boat is almost exactly like my 16' Starcraft. The benches provide a lot of the structural support to keep the sides from flexing. Without them, your sides are trying to flex out on the sides and fold your bow back to your transom. You definitely need to add some structural support to the sides to keep it from flexing. You can either do like mentioned in the earlier post and use plywood on the sides or you can run several pieces of aluminum angle down the sides to sturdy it up.
 
Thanks for the help talking this problem out with me. This is the direction I am going in right now. I went the other day with another fellow in the boat and the flexing issue or nonissue didn't show up, no leaks on the seams, no funny feeling and no porpoising cause he was in the front. It appears I am on my way to getting it more solid as a craft.

The stern heavy issue still exists, and when I'm not watching the suns-spurs I'm outside working on the jackplate. I'm first trimming it up and taking out 2/3" of the setback by using less of a motorboard, we'll see if that helps some. Its a longshaft motor that was still a little too deep. After I go out again, perhaps tommorow afternoon, I will post how it planes and we will see what tweaks should be done.

I will also post a full pictorial when I get done with this boat.
 

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