Way back in late 2007, when we first started this refit, the boat was outfitted with Super SeaMaster marine engines, turbocharged and intercooled Ford Super Duty 534ci early 1970’s monsters that developed 400hp at 3200rpm. All that power was pushed through 1-1/2″ Aquamet 17 shafts (see the Parts For Sale page if interested!) to a set of 3-blade props. After repowering the boat to Cummins 450 Diamonds in 2012, which came with 1.5:1 gears, and finally installing the new 1-3/4″ Aquamet 22 shafts, it’s always been a big question what size of props would work best. I can only estimate the weight of the boat when she’s done. A buddy of mine — and Roamer guru extraordinaire — has manufacturer’s data indicating that my boat should weigh in at around 32,000 pounds. But other Roamer 46s I’ve heard about range up to 50,000 in aluminum and 55,000 pounds in steel (with Detroit 871 power that weighs 2x the mass of my Cummins). So I checked with Miller’s Island Propellers and, what do you know…the ol’ 3-blades just might be perfect for this HP rating gears, assuming the weight comes in around 37,000 pounds. In any case, they’ll work fine as the sea trial props to give me a baseline.
I’d barrier-coated and bottom painted the props way back in 2008, since the plan then was to splash the boat and continue the refit at the old marina where we’d found her, and that marina’s got a serious fouling problem. Plans changed, so all of the coatings had to come off before going to the prop shop.
In the pic above, the props are installed loose on the shafts. I won’t permanently install them until I have a chance to test the fit with Prussian Blue and lap them with valve grinding compound if necessary. I’m also waiting on a 2″ socket wrench so I can torque them down. Stay tuned…
Next up on our 1969 Chris Craft Roamer 46 Refit: Installing the Props