November 06, 2006
Rescue Craft Sea Trial - Double the Performance
I just got back from a fantastic sea trial. As part of our quality control program, we sea trial every boat prior to delivery. Each boat is taken through the paces and pushed to the limit to insure everything is functioning properly. Should there be any failures we want to know about them before the boat leaves our facilities so we can fix them while the boat is still in our possession.
This morning I was fortunate to get out on two identical RIBCRAFT 4.8 Rescue Craft. These two boats performed perfectly. I’ve been on hundreds of sea trials and they just don’t get old. Whether with prospective customers, marine editors, or colleagues, the 4.8 is one boat that never disappoints!
The two 4.8s were equipped with the 60HP Mercury Big Foot four stroke engine. Though not always a favorite of our riggers, these 60HP engines moved the boats perfectly. Topping out right around 40 mph, the boats easily held through the turns at full throttle. What’s more there was zero cavitation. I hope to have the pictures I took of the boats tomorrow - I’ll be sure to post when I have them.
Posted by ribcraftusa at November 6, 2006 01:48 PM
Comments
Curious about how you had the 60hp engine propped? Aluminum or stainless? Diameter and pitch...I'm trying to get a 60hp Yamaha 4-stroke propped right for a 15' RIB.
Thanks
Posted by: Paul at November 18, 2006 08:47 AM
Hi Paul:
Thanks for the question. The 60HP Mercury Big Foot's were propped with an aluminum three bladed prop, 13 3/4" X 15R. Prop size and pitch can vary greatly from engine to engine and boat to boat. Even within the same model line, prop size can change based on the weight of the boat and the horsepower. Good luck and let us know how you make out.
What kind of RIB do you own?
Posted by: Fred at November 21, 2006 05:40 PM
Hi Fred,
Thanks for your reply. I have an AB Inflatable (15') with an aluminum hull. I found that by dropping the motor one notch that the current prop did a much better job. Yet I'm looking for an aluminum cupped prop that will fit my Yamaha F60. I can pull 5700 rpm with 11.1 x 14, so a 10.5 x 15-15 1/2 might be a good choice. Any brands you think are superior? The Web has many prop sellers will all the same great claims...don't know who to believe!
Thanks,
Paul
Posted by: Paul at November 24, 2006 11:54 AM
I really don't know Paul. Some of the best prop advice out there can be found in boating magazines that test out a whole series of props and compare the results. The nice thing is that you can see the relative differences without plunking down any cash yourself. As you have discovered, choosing the right prop is something that still relies heavily on trail and error. Even in larger boat situations where these things are carefully calculated repropping is quite common - so you're not alone.
I have personally just gone with manufacturer's props and left it at that, but to be honest I have never been overly concerned with going as fast as possible. Unfortunately, the best advice I can give is to test out some of the props you've seen on the web. I'd love to hear how you make out.
Good luck.
Fred.
Posted by: Fred at November 27, 2006 04:35 PM
I am in the business of boat sales and repair. I have purchased props from numerous manufacturers, the company that I use all the time now is Power Tech Props. Phone Number 1-800-736-7767. These guys are very good at what they do. Just tell them type of boat,motor,and problem. They'll come up with the right prop for you.Good luck.
Posted by: Ed at December 2, 2006 06:02 PM
