Hey all. There isn't really a "motorhead" section to this forum, and we are primarily recreational boaters, so I figured I'd give it a shot.
We have a Sea Ray Sundeck 240 2005, with the Bravo 3 behind a 5.0 Mercruiser. All my prior experience was with Alpha drives, and for the most part I love the Bravo, especially in reverse in a tight slot, not so much trying to walk around into the wind, amazing performance in shallow water with it trailered. Coming out through the really bad water 3 weeks ago took our gimbal from loose to sloppy, so were off the lake for a month while I rebuild it. (would coulda shoulda done it over the winter)
The 5.0 is a fantastic motor, most of the time. We get pretty excellent mileage, about 11-12gph at 27-30mph cruising, 7-8gph water sports. Top speed of maybe 37 at 15.5gph with an empty boat, the Bravos don't seem to shine at higher speeds.
The issue we run into is getting on plane with a full load. Once planing we are ok, unless we get into really bad chop (like the channel May-September), then it gets a little dodgy, the big bow likes to "scoop" if you come off plane(looking for a bow cover, gimbal repair first). In the last bad wind storm, we were at maybe 60% load, and the margin of performance was reassuring. We are running Hill Marines 4x4 20 pitch props, a huge improvement from the stock 21 3 blades, really improved the performance and handling of the boat, and improved our margin. Big vote of confidence for Hill. Great service and very fast shipping. I'm not excited about further reducing to the 18 pitch, as I really don't want to give up my cruise performance, and RPM wise we are about right with these props. (I underpitched the last Alpha, great for launching, but you had to manually limit rpm.)
So, Power Adders Has anyone experimented with light nitrous dry or wet shots for short term power, 20 sec or so to get the motor higher in the horsepower curve? Maybe 50hp? Bottle and piping wouldn't add much weight and we have space. Engine isn't really prepped for nitrous, and speed isn't the goal, my hope is a light enough shot doesn't require timing changes, and just makes up for the lack of atmospheric pressure, and the fuel injection can adapt and richen. I also have other projects that I'd like to try nitrous on, so the costs can be spread a little. (cinders hill climb truck, clearly a bad idea, isn't that the point?)
My other thought was a manifold for 3-4 12v blower fans into the intake. Would not be a turbo, but might compensate for the altitude somewhat? A belt driven supercharger is a real solution to the same idea, but I don't want to run it all the time, and I'm not sure how they would do with an electric clutch on them (and fairly expensive). The Mercruiser 6.0 would be perfect, but unless I can find a wreck, would cost a high percentage of the boats worth.
I realize that the rational answer is to take less stuff fewer people or stay fewer days, but with Dangling Rope closed, the fuel jugs alone put us heavy, and we want our cake and to eat it too.
