1970 Seafari conversion to CC

[afishin82]

I plan on installing the bulkheads and am trying to figure out where the center of gravity of my 60 gal fuel tank shoul be. Since I am putting a 24" setback bracket with new 4stroke and 25gal transom livewell in I know it needs to be moved forward just not sure how far. If anyone can has an idea please chime in thanks.

[flyingfrizzle]

Originally Posted by afishin82

I plan on installing the bulkheads and am trying to figure out where the center of gravity of my 60 gal fuel tank shoul be. Since I am putting a 24" setback bracket with new 4stroke and 25gal transom livewell in I know it needs to be moved forward just not sure how far. If anyone can has an idea please chime in thanks.

With all that weight of a 4 stroke, 150 lbs bracket and 175 lbs of live well water you will need to move it about a foot or two in front of the boat. Kidding aside I would go far foward as possible.

[Bushwacker]

Originally Posted by flyingfrizzle

With all that weight of a 4 stroke, 150 lbs bracket and 175 lbs of live well water you will need to move it about a foot or two in front of the boat.

Frizz is about right! A Seafari like you started with is about 400 lbs heavier than a CC, and most of that weight is up front in the form of the bulkheads, cabin top and door, windshield, bunks and anchor locker bulkhead. So far you have removed all of that, and now you're talking about running a motor about 75 lbs heavier than mine, PLUS adding another 175 lbs of water right at the transom! You've done everything possible to insure a stern heavy boat that won't plane below about 25 mph!

The CG on my boat is about 6.5' fwd of transom. That location is real obvious because the aft cross member on my EZ Loader roller trailer pivots, tilting the boat about 30 degrees when the CG passes over it. My boat is a stock Seafari with a 34 gallon tank plus 2 batteries, a 1.8 gal oil tank and a 9# anchor + 6' of chain +100' of line in the stern, and a 9# anchor on bow with 20' of chain and 300' of line in anchor locker. Motor weight is 427 lbs and bracket is a 30" Hermco; not sure of bracket weight but I'm guessing it's somewhere around 150 lbs. You could use those numbers to set up a moment balance about the current CG to solve for the CG location of the bare hull (assume it weighs about 1100 lbs). Once you have that you could then subtract the moments for the stuff you've removed and add the moments for your heavier motor, live well, gas tank, and console, etc., to figure out the new CG.

I would strongly suggest using Coosa in the new transom and some sort of composite in the deck in the rear of the boat and maybe plywood in the front of the boat to make it a little less stern heavy. I'd also try to minimize setback on the bracket; Don Herman said he can make his with 18", 24" or 30" of setback. I'd also put that livewell in the front of the console, assuming there is enough room for it up in the bow of the boat!

[afishin82]

I am also looking to get rid of the windshield, bowrail, and bimini top that came off the seafari. if anyone is interested its yours come and get it.

[afishin82]

Got quite a bit of work done on the boat. Braced up the sides with some foam and glassed over the entire sides with a layer of 1708 and 2 layers of 1.5oz mat. Then added a ledger using .5 in celtec and glassed over with 2 layers of 1.5oz mat. This stiffened up the hull sides significantly! I got my custom 70gal tank built and it fits perfect. Started cutting the floor peices and bulkheads using .75in celtec and have been lookin for a nice console and leaning post/livewell. Marine connection has some nice stuff but big$$$. Might have to bit the bullet and get it.

[72potter20]

I'm very curious to see how that transom door turns out!

I'll be using a fishmaster t top if I can't find a deal on one locally. The fishmaster is about 1g and folds.

[afishin82]

Originally Posted by 72potter20

I'm very curious to see how that transom door turns out!

I'll be using a fishmaster t top if I can't find a deal on one locally. The fishmaster is about 1g and folds.

Nice I was thinkin no t-top, a pathfinder console, and twin vee leaning post livewell.

[afishin82]

So wat do yall think of the tank? I need a livewell and dont really want a leaning post/livewell. I really wanna do a transom 20gal livewell but am now havin doubts after all the feedback from yall. Will it make a noticable difference if I put a leaning/livewell instead of a transom livewell?

[Bushwacker]

Originally Posted by afishin82

. . . Will it make a noticable difference if I put a leaning/livewell instead of a transom livewell?

YES! You can add the livewell later. Suggest you get it running, determine how stern heavy it is and how bad it porpoises and then start shifting ballast around (trash cans full of sea water) to figure out the optimum location for the weight of the live well!

[afishin82]

Thank u sir! I will do that. U know a good way to install the floor in sections w/o putting bulkheads in on every seam?