Might have to find another 24 guy for this one because I can tell you if I had to raise my floor enough to "cover" my motor I would have about a foot or less of freeboard.
I don't think you have enough of a deep vee for anything like that.
Johnny, go with a single, preferably a 350 MAG. Even with twin 3.0 4s, the spacing is gonna be tight, as, like you said, can't push the props too far out. With the mag, you have 300 HP. Want a bit more, go with the 7.4 standard, that gives you 310, but at a weight trade-off, no real difference. The 6.2 will give you 320, but a newer motor and a bit more pricey...3.0s were rated at 135 HP, so getting them close to get the prop spacing right (and make maintainence a PITA!!!) will only get you 270 HP...
Johnny, what about a 315 Yanmar? Too tall?
You're gonna have exhaust routing issues with the gassers as well...The way I look at it, you would probably have a 6" step up if you located the Yanmar under the leaning post (where we used to install them at Stamas), the hollow of the leaning post inside takes care of clearance for the heat exchanger and turbo (the highest points of the motor) without having any deck height increases if you were to move aft with the engine...unless of course you want to move it all the way aft and do a V-drive...
Yes v-drive is out. Your point about engine mounting is the same as I am trying to make. I already have 20"+/- from hull to stringer top. That means that if I raise the deck 4", I now have 24". I am not sure how much clearance I need between hull and bottom of engine. But I know that this 24" gives me a lot of room to work with. How does the pocket allow me to lower the engine. Is it because the front doesn't have to be tilted up as far?
I like a 2" minimum clearance between the oil pan and the hull bottom. This is to keep the pan from sitting in bilge water, which inevitably seems to happen on a lot of I/B and I/O installs. Rusting out oil pans is not a good thing. But you also have consider clearance for ancillary equipment mounted to the engine (fuel coolers on Mercruisers are good examples), as well as tranny bell housing clearance.Prop pockets have several benefits, as well as some drawbacks. The main benefit is significantly lower engine height, thus a lower deck. Think about the angle the shaft has to be at coming off the output flange of the tranny in order for the prop to clear on a standard I/B install with a standard keel. Now remove a good portion of that keel by creating a prop pocket, and the prop can be moved upward a good distance. Thus, the down angle of the output flange of the transmission can be significantly reduced, and, by geometry, the engine naturally has to be lowered...thus lowering your deck height. Note the various down angles offered by Hurth on this chart...http://simplicity-marine.com/Hurth-ZF.htm The other significant benefit of a shallower angle is increased prop efficiency. A prop works best when it's thrust is parallel to the hull bottom. While that's never gonna happen on an I/B, less of a propshaft angle in relation to the hull bottom gets the prop closer to the desired parallel position.The main drawback to prop pockets is loss of stern lift as the water no longer has a relatively flat section of hull to work on. This is more pronounced with deeper V's than your hull (I assume 12* of deadrise), but that loss can be compensated with larger tabs than an O/B or I/O version of the hull might use. But you need tabs anyway as I/Bs can't be trimmed, so it's sort of a moot point.I'd like to see you get this done, it just takes a little thought...
