It dawned on me the other day while we were running up the Cumberland in our 327F-powered "almost Commander" that even around 2000 rpm, the motor was chugging along and we were going around 12 miles per hour. Leaning over the side and looking at the splash on the side of the boat gave the sensation that we really were NOT moving all that fast, and the motor was indeed, like it was in a truck running uphill.

Marine motors really DO work a lot harder than in a car. The life of a boat motor is pretty un-eventful most of the time becuase they sit at the marina most of the time wondering how long it will take their owners to earn enough money for fuel or find the time to burn it. When they do work, however, they have to work hard, and even at a low cruise the torque is what gets the job done in a boat.

A car by contrast is running easy at 2000 rpm. Take a look at my moring commute, and note the difference in rpm between 70 and 80. Not much.
By contrast, the car is loafing, while the boat is working harder to maintain 12 miles per hour.

I have a 1948 22 ft Sportsman that has a 350 Chevy in her; 1:1 gears. She typical is going the same speed as the tack. In other words, at 2,000 rpm's she is at 20 mph. At 12 mph and 1,200 rpm's she will cut through pretty rough water without pounding. Of course without a full bow, she will take water over the bow in big waves as there is not enough reserve bouyancy in her bow. She cuts, but does not go over the waves.

I took her on a 250 mile trip from NYC to her new home in Annapolis in 1997. On the outside in the ocean, and then up the Delaware bay. The Delaware bay is one of the worst places in the East Coast, the Coast Guard confirmed this as we left Cape May. An owner of a big 45 ft sport fishing boat said he has had waves crashing on his boat so hard he thought she would break somewhere (like the windshield that the waves were hitting).

We hit some bad weather as well, we turned into a river as the waves were coming over the boat and landing in the back. The boat chugged right through it; my crew mate was looking for any alchole on the boat to calm his nerves (there was not any).

The engine seemed to just effortlessly run at the lower rpm's, hardly using any gas compared to the 3,000 rpm she would run in flat water (top speed is around 45 mph and she will pull many skiers with her custom ski pilon).

Your boat with the round chines is such a different boat (as you know with your old wooden Chris's) with a much better ride in bad weather. Much like a Lyman I would think.

Kevin

Oddly enough, the hull on our 1966 (fiberglass) Sea Skiff is a departure from the traditional round bottom with keel, you find on virtually ALL other (wood) Sea Skiffs, and essentially all Lyman boats too.

Our fiberglass Skiff (of which only 80 were built) has a hard chine, with moderate deep V, and with a small keel, and this is totally unexpected with a Sea Skiff. My friend, Wilson Wright, was surprised to hear CC even made a fiberglass Sea Skiff. Most Chris Craft guys would be surprised too, so I have spread the word about this one on the CCABC web site and with ACBS too, just as a point of information.

Regarding the speed and rpm, I think I could trim tab it a bit for better efficiency, but during the recent runs the tabs were fixed and not able to be adjusted.

Here is a photo of the unusual feature on a Sea Skiff, called a hard chine!


These three photos were taken by the previous owner as she sat in upstate New York near Lake Ontario






Here's what she looked like as she arrived in Nashville, shrink wrapped and needing a TOTAL restoration. The hull was good, motor block was good, but risers, transmission, carb, instruments, all flooring, steering, upholstery, etc., all had to be replaced.






A fair amount of wetted hull surface on this boat, more friction than the normal Chris runabout which has a nearly flat bottom at the transom.







Not a particularly fast hull, but very comfortable and dry!



Your trip across Delaware Bay sounds like it would make a guy want a stiff drink afterwards, ha! Great story.
One thing for sure, those small block Chevy motors in a runabout are very sweet! My buddy Mike Flood, with the Hackercraft, has a 283 CC motor in his and it will run fast and does not seem to be working very hard. Our Skiff doesn't seem to be working hard either, except if you lean over the side and see what is really happening almost in slow motion, then you realize how SLOW you are really going, compared to the rpm. When compared to an automotive gear, the boat is working hard, and the car is loafing.

regards,

Paul

I is time to start thinking about rebuilding my SBC's this winter. I am wondering if it would be worth the extra investment to go to 383 cubes with some type of cam upgrade. Hum??? This could get interesting.

CW

383's can make a gob of torque, and now there are ample parts available without having to modify a 400 Crank. I say if you are rebuilding, go ahead and STROKE IT... As they say there is no replacement for displacement.

My preference would be to keep the compression a tad low so that you could run on 87 pump gas (OLD 89 gas). We wouldn't want to be chatting about burned pistons next spring after using that old 'marine grade' gas.

Since we would need a reverse rotation engine I wonder what the availability of aftermarket cams would be? Surely Mercury has a nice cam available for this application, but it may be a bit pricey. Im sure it wont be an issue. Isky has one 201264/271-12 that is only $130, it seems to be relatively mild but its only an example from my notes.

One thing to consider is to not get too crazy on the CAM timing. If you get too aggressive you will have some negative pressure and suck water into the chamber, that would be a day ender. Plus the aggressive CAM would not be tuned to run in the low RPMs and would idle rough. Plus we need that low end torque so its a moot point. (I know its hard not to go overboard when looking at the components)

Most of these thoughts came about when a friend of mine was looking at getting more power out a Caravelles engine, then we realized it was a 5.0 instead of a 5.7.

Just some thoughts....

RE

Chris

If you can find a pair you would be much happier with 454s. Big cubes mean big torque.
I was able to find a pair of Crusaders with only 600 hours on them and boy do they make a 31 fly.







Don
FXA 31 2074 H