Well I have most of my bracket mold cut and assembled. I used 3/4" Melamine sheets to form the mold so that I could wax the surface and have few to no sticking issues. I sometimes use MDF sheeting and then line it with plain white Formica which works better for doing curved parts. I decided to make it 22" high to the top of the swim platform with a 22" set back. Not a 100% sure the motors will get a full tilt here but if they don't I will modify the rams so they will not over extend and hit. I am much more concerned with minimizing set back vs getting more tilt. If I can tilt the motors up enough to get past the hull bottom and also clear the road when on the trailer then that will be all I need. Just want to help the balance by keeping the setback short as possible with out notching the transom and loosing the factory fish boxes across the back. The flotation tank will be 60" wide to go all the way out to the start of the 3rd steps. That will leave me just enough room for trim tabs or k planes. The swim platform will be 72" wide extending 6" past each end of the floatation tub. The flotation tub will be mounted low as possible, at 2" up from the hull bottom to clear the rise of the water rolling off the back of the transom. The tub will also have a 20 degree vee on the bottom to match the second step deadrise so that it will parallel with them. This will leave just enough room under the bottom of the tub for a garboard plug set center of the transom. The vee section of the tub will be angled slightly upwards to the rear point to allow an additional 2" of clearance for the water surface. This should be enough to keep the flotation bracket from dragging the water when the boat is running with no trim.
It was fun figuring out all the angles when cutting the pieces and designing the bracket. The transom in the 25' seafari is about 12.5-13 degress just like some of the other seacraft hulls. With the transom lay back and the upwards taper of the flotation tub aft made for some complicated compound angled pieces that were a little brain racking to figure out but not so bad once it was plotted out on paper.
I made the sides of the tub section of the mold taller than needed so that when I glassed it in the top edges would not roll away from the side of the mold when the fibers curl out past the top edges. I will just cut it to height with a thin cut off wheel once popped out. The front side that will bolt to the boat will have a 4.5" notched lip inwards to allow for the swim platform front lip to lap over it and in place while maintaining a flush surface. I actually cut the last 4.5" off of the front side of the mold then used a 1/4" piece of ABS plastic to space the top strip inwards towards the rear of the mold then backed it with some scrap 3/4" ply that was scrap from the transom core. I also added a 6" wide strip of 3/4" ply to the top of the front of the mold just to hold it square. In the pics below you can see the stepped section. I will contour the corners tonight with clay and round them with my radius forming tools. Then it will be ready for waxing and layup.
Here is a few Pic's:
Cut and ready to screw together:
Attached together:
Showing the notched edge for the overlap of the swim platform:
The sketch and design...lol
