PDA

View Full Version : How much bottom flex ?



TX19
05-28-2002, 04:09 PM
If I lift my boat with a floor jack located just in front of the pump, directly below the oil pan, how much should the bottom flex up toward the oil pan?
I am using a 18" long wooden 4" x 4" between the floor jack and the bottom of the boat. The boat is a TX 19 splash. The bottom is flexing up about 1/2 inch when I lift it with the floor jack.
Is this flex normal, or do I need to strengthen up the floor of the boat below the engine?
Thanks in advance for any help!

ratso
05-28-2002, 08:22 PM
Sounds like you need to strenghthen that area. 1/2" is a lot of flex!

bajaruner
05-28-2002, 10:20 PM
Are you trying to remove the boat from the trailer or do you feel there is bottom damage?

flat broke
05-29-2002, 07:58 AM
A lot of times a light layup is going to result in flex in the hull. If you've had your pump out, how thick is the hull where the transom adapter goes? Does the deck flex if someone sits on it? It might not be a problem, but rather how the boat was intended to be laid up. The fewer layers of glass sucking up resin there are, the lighter the boat is going to be. Do you have any background on the boat? Did it used to be a race boat? If the rest of the boat is solid and thick, perhaps you have a delam problem in that area. Sorry there's not a quick answer on this one.
Chris www.liquidaddiction.net (http://www.liquidaddiction.net)

TX19
05-29-2002, 06:53 PM
I am not trying to lift the boat off the trailer. I am trying to determine if the bottom is flexing and how much flex if any is normal I think I have a problem with the bottom flexing and creating a hook at about 80 mph. The boat seems to nose over and runs very "wet" at that speed. There is no measureable hook in the bottom of the boat on the trailer.
The boat has not been raced competitively and has had mild (stock 460) engines until the last 5 years. I have had the pump out and the glass there looks good although the deck will flex if someone steps in the middle of it. I see no signs of delamination anywhere on the boat.
I think I may have some bottom flex at speed that creates a hook and don't know how much flex it takes to make a difference in the attitude of the boat.
Any thoughts are appreciated!

flat broke
05-29-2002, 09:39 PM
TX,
I would think that if the hull was flexing right in front of the intake, you would see some pressure variations on the intake side of the pump as the hook might cause some airation as the water bends into the hook and then around the lip of the intake. Could it be that the intake itself is causing the hull flex? Perhaps running an intake brace between the intake and the stringers would help tighten everything up. Call Jack at MPD, Tom Papp, or one of the other guys with a lot of racing setup experience and see what they say. Odds are they've already run accross this problem in another customer's boat.
Good luck,
Chris www.liquidaddiction.net (http://www.liquidaddiction.net)