I know this isn't a RIBCRAFT but I thought you all just had to see this RIB. It does raise the question - how much power is too much? The RIBCRAFT 7.8 with twin 150HP engines moves at 50+ MPH; that's plenty fast for me!
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January 26, 2007
January 24, 2007
Leaky Tubes?
Are My Tubes Leaking?
For departments using RIBs in colder climates during the winter, this is a common question and concern. The answer nearly every time is NO.
Because the tubes are air filled, they are susceptible to temperature change. Changing temperatures cause the air pressure inside the tube to fluctuate. The tubes become harder as the air expands on hot days and on colder days the air contracts making the tubes softer.
This is extremely evident during the winter for fire departments who store their boats inside the station until needed. Many first time RIB users panic when they move the boat from the 68 degree station to the outside where it’s 35 degrees. Within minutes the air inside the tube contracts and the tubes soften.
To minimize this effect, I recommend putting the boat outside in the cold for a half hour and then pump the tube up as much as you can with the foot pump. Then bring the boat back in. The tubes will become hard once inside, but hopefully the next time you go out, the tube change won’t be as extreme.
Similarly, during the summer, you could be out on the RIB in the afternoon and all seems fine until the next morning when you go out and you notice the tubes are soft. What happened? Much like at the fire station, in the afternoon it could have been 90 degrees and the next morning it was only 70. If you notice the tubes are softer in the morning - be happy, you're lucky. The pressure relief valves worked the day before as the air pressure in the tube expanded dangerously in the heat, the valves worked - releasing some of the air to maintain a safe operating pressure. This protects the tube, but when the air temperature drops as the sun goes down there’s less air in the tube and thus the tube becomes softer. When this happens, be thankful, because the alternative would be much worse. All you need to do is simply add a little more air with the foot pump. This rarely occurs, but it’s not unusual to have this happen once or twice during the summer in New England.
Bottom line, if you suspect your tube is losing air and all the chambers seem to be losing the same amount simultaneously, then you’re very safe in assuming your tubes aren’t leaking. They’re just adjusting to their surroundings.
January 17, 2007
Aluminum or Stainless? (Props 103)
What prop material is best – Aluminum or Stainless?
Aluminum props: The most common and deliver good overall performance.
Stainless Steel props: Used as an upgrade and deliver better top end performance
The economical choice, aluminum props provide more than adequate strength and are easily repaired. The downside is that it’s fairly easy to bend or nick the blades should you hit something. Comparably, stainless steel props are stronger and generally more durable; that being their greatest advantage.
The strength of a stainless steel prop will help maintain engine performance because they are resilient to the small nicks and bends that can occur with aluminum props. Additionally, because of this strength, stainless steel blades are thinner which results in better efficiency and performance. A thinner leading edge will create less air bubbles on impact, resulting in less cavitation thereby delivering better performance. Stainless steel props generally offer improved performance, better acceleration and higher top end speeds within the same pitch as an aluminum prop.
The major downside to stainless props is that they are much more expensive than their aluminum counterparts. Some view their strength as not only a positive, but a downside as well. Should you hit something (rock or hard object in the water) the stainless prop won’t “give way” like an aluminum prop and the force of impact will be delivered straight to the lower unit. If you operate your boat in waters with rocky coastlines and bottoms it’s often recommended to choose an aluminum prop. In my opinion, I’d much rather replace or repair an aluminum prop than my lower unit.
For more information on props, check out this helpful link. http://www.props.net/propsnet1.html#pitch
January 09, 2007
On the Water with the USCG Auxiliary
I was catching up on some reading the other day and was flipping through the November issue of PropTalk, a great publication that focuses on power boating in the Chesapeake, and came across a nice little article on a Coast Guard Auxiliarist using his RIBCRAFT 5.85 for patrols, A Day On Patrol With the USCG Auxiliary, by Art Pine.
Jim Welday (a RIBCRAFT owner since 2003) has been a member of the Coast Guard Auxiliary for over 14 years. Welday uses his RIBCRAFT 5.85 for patrols. In the past year alone, he has logged more than 300 hours on the boat patrolling the waters of the Chesapeake.
Before purchasing the RIBCRAFT, Welday used a hardsided 21’ bowrider for his patrol duties. As the article mentioned: “This one [RIBCRAFT 5.85] is the ultimate in search and rescue craft. Besides the usual array of safety gear, it’s rigged with Auxiliary patrol signs, red-and-amber flashing strobe lights, a Sampson post for towing, and twin bridles and towlines. Welday can easily top 25 knots in an emergency…”
The article continued recounting an average day on patrol with Welday and highlighted some of his more memorable rescues over the years. The author concluded the article by saying: “Welday’s new boat has proven to be a good choice for his search and rescue efforts. The rigid inflatable ‘works a lot better than conventional boats,’ he [Welday] says, enabling him to ‘get up closer to other boats and talk to people,’ rather than having to shout or use a loud-hailer. “That way, you don’t have to worry as much’, he says.”
If you’re interested in reading more about this, I highly recommend contacting PropTalk for a subscription and a copy of the November Issue. It’s a great magazine that’s not only a good read, but free!
PropTalk, www.proptalk.com
Here's a picture of Jim Welday's 5.85 from a few years ago while on patrol.
