were must be located the longitudinal center of balance??

[roberto alvarez]

Hi, when i use the F233 with a single omc 225 all the time is bow up and stern down, not very straight runer,this have no seat boxes or anything more on the cabin, this mean a light hull, i add like 400 pounds on the bow as a test and was able to run at 25 Knots at 3000 rpm, before this test the engine rev at 4500 to planing and 20 knots max speed at 3500, based on this did some on know the performance of this stock boat,is a 1978 thunderbird 233.
and were the center of balance must be???? thanks

[David]

Adding weight should slow you down, not speed you up. You should be able to tuck the drive to a negative trim angle to keep the bow down. Are you able to do this? Just a side note though, 233's like a lot of bow lift at speed.

[roberto alvarez]

Hi David, it have the omc stinger drive unit and no trim as in another drives can be obtained
as can see on the photos the boat has no seats or other , and with 7 human´s the angle exed the 30 degree ( like a bad tuned or underpower boat) but with my brother and a empty 50 gal steel fuel tank on the bow the ride was at less rpm the same top speed, and here the second Question, many 233 boats here an in youtube videos have a better speed and fuel range than this with less HP, my engine is the 318 Cubic Inch GM, maybe is too heavy on stern??
i cant found any performance chart on the web, did you see any???
And I am Sorry By My Spell, i think on spanish and some ideas can be hard to explain

[David]

Roberto, I cannot determine the trim angle from your photos. Perhaps you could post one showing the drive in the running position. As for weight, my 233 has twin 350 Chevrolet engines so your 233 is not too heavy. I suspect your problem relates to trim angle.

[roberto alvarez]

Last night i open the formula vintage boats section and based on the instruments panel dashboard , and windshield is a 1973 hull, will try to take a video from the boat and check again the trim tabs and engine installation.

[roberto alvarez]

LCG is what i need to know for a Prismatic Planing Hull i found the formula now need know the weight, a friend send me a design book from 1968, he is a boat designer and told me, AT THE END, LOCATE THE LCG IS IS TEST AND TRAIL SO REFUEL AND TAKE NOTE OF EVERY CHANGE

[roberto alvarez]

PROBLEM SOLVED DAVID, I REPLACE THE PROP, IT WAS A 13x16 AND THIS ENGINE MUST USE A 14x18 I CANT FIND A 14x18 AND TEST A 14x14 AND SEE A BIG DIFERENCE, ALSO FIX THE TRIM TABS NOW I CAN FEEL THE BOW ON THE WATER

[David]

Glad to hear you have solved your problem.

[roberto alvarez]

YES,Now i am ready for a 600 mile off shore trip around Baja California Coast, if i win a bid on ebay for a 14X18 prop.