RIB Dinghy on CD 22?

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Phil Barnes

New member
A few dinghy manufacturers are making light weight RIBs in the 7 to 8 1/2 foot length range. Some in aluminum and others in fiberglass. Weights can be as low as about 75 to 85 lbs. The V in the bow on some is fairly shallow, making storage on the cabin roof less cumbersome than a deep V, which would need some sizable brackets for support. The weight is well within the capability of a 2 inch Garhauer Lift Davit, which is rated at about 150 lbs. I have seen photos on the site of a Portland Pudgy on the roof of a CD 22 so this would be similar, but perhaps lighter. I think that owner also used a Garhauer Lift Davit to put the Pudgy on the cabin roof.

Is anyone doing this or considering a small lighweight RIB as a dinghy for a CD 22? What issues do you see with this?

Mercury, Defender, Achilles and Zodiac are manufacturers with RIBs in this size and weight class. Defender Marine has a good listing in their RIB section. Sort on boats less than 8 foot 11 inches and you will see a number of them.

Thanks in advance for the input!
 
We a well paired roof rack to position it just off the roof using a couple sets of kayak type supports, I don't see why it wouldn't work. Why do you want the rib over a lighter air floor? Speed or puncture resistance? Friends with RIBs would tell you the punctures still come too easily.

Greg
 
I carry an "Alaskan" inflatable about 50 pounds and on one trip, I left it un-inflated and rolled up and had it squarely centered on the cabin top. I wound up in some pretty big seas and felt that that weight, that high was a bit spooky, adding to some lateral instability. Admittedly, I do carry the inflatable nearly the same height now, but it is moved aft (the center of the weight) now about 4-5 feet and the width of the boat aft is greater, decreasing the feeling of instability. It is also easier to get up and down onto the more rearward position than onto the full cabin top.

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Harvey
SleepyC :moon
 
It certainly could be done. We carry an inflated 9 1/2' air floor, about 60# on top, with a Garhauer Davit (I would get an extended lower unit, if buying again--although ours works OK... Also I would put our Radar further forward, if doing again. If you had to, it would be possible to put the tender upside down. I would not want to get too much weight on the cabin top--because of increased center of gravity--the top can take it structurally...

One disadvantage of the light RIB's is that few of them have a flat floor--It may not make a difference. Our air floor is flat, and keeps us above any water which might get in the boat from spray or surf, etc. (still a good idea to have a small manual bilge pump and sponge aboard.

Not sure why Greg's friends are having punctures with RiB's--maybe not much "V" in the hull, to keep the pontoons off the rocks/shellfish, or that the fabric is too light or not tough enough. We had a used Avon Hypalon 12 1/2' RIB we used 3x daily to take dogs ashore for 5 months each year x 4 years, and then another 6+ months in Mexica, Central America and Caribbean. No punctures, and only a few scratches. But that boat weight with a 15 hp and fuel/battery was about 375#--with commercial 25 hp, over 425#...

I would agree that in many ways an air floor is a better boat, than a thin floor, light weight aluminum or fiberglass RIB.
 
Good comments. Thanks! I was interested in improved performance with a rigid hull and less risk of puncture. In terms of weight on the cabin roof, most dinghies are going to weigh in at about 50-60 lbs. If one puts two plastic kayaks on the roof at 50 lbs each you are at 100 lbs. Midway between is the 75 lbs more or less in a small lightweight RIB. Greg notes that a rack is a good idea to keep fiberglass or aluminum from sitting on fiberglass. Less weight on the cabin roof is probably always better although most of us have at least 50 lbs up there in an inflatable dinghy. Ease of repair while in remote locations is a consideration. I can patch a PVC or Hypalon dinghy easily but repairing a hole in an aluminum or fiberglass RIB is another process and I might not be carrying everything needed. I think it can be done easily with the lifting davit and thoughtful storage arrangements using a rack or cradle. I am still weighing a quality inflatable dinghy with an air floor versus a lightly built RIB. A thin fiberglass or aluminum floor may not provide any real advantage. Leaning toward the Hypalon inflatable with air floor at the moment . We have a small older PVC air floor dinghy now that will need to be replaced soon. Always good to have a choice and the lightweight RIBS were not an option until recently. Thanks again for the input.
 
Phil,
I was driving by West Marine and looked at the West Marine 10' lightweight dinghy a couple of days ago. The boat is 10'1" and weight 95#. My impression is that the floor was very thin--and I suppose could be punctured. (Of course fiberglass is easy to do a quick and dirty repair with epoxy--probably easier than a good Hypalon repair)--but there still is the risk of puncture of a tube. Aluminum can also be patched readily with epoxy and cloth (I have done this in several aluminum boats). I found the most of the wear on our RIB was the front V and the keel--and that was where I put sacrificial glass, and epoxy, with aluminum flakes in it each year. The bottom was painted with a hard antifouling paint, so it was easy to "hide" and repairs.

The boat's "Deep V"--was not really a deep V--our larger Avon was about 18*--I would have estimated this was less than 10*--and the transom "folded"--so there was fabric attached to both the fiberglass hull, and the transom. The biggest problem in any inflatable boat is delimitation of fabric from the transom--and this fold is at a critical place. The boat with Hypalon and a molded transom to bottom, was 113#--some of that in the fabric and some in the fiberglass.

Interesting that our 9 1/2' inflatable floor was rated for over 100# more capacity than the RIB 6" longer.

I suspect that the RIB would be faster with the same hp--but the seaworthiness about the same.

I cannot speak to the "rigidity of the current 25's roof, but the 2003 I had, had a very flexible center part of the roof, which was not cored--where the current 2006, 22 I have, has a cored center of the roof, and handles my 180# without problem.
 
If you are leaning towards air floor, the Achilles LSI series is an excellent choice. The LSI260 or 230, will be easier to get on /off the roof while inflated due to the narrower beam and lighter weight, and both are within the size you are looking for.

I run the larger 9.5' LSI290 and it's very capable for island hopping or extended day cruising with a 6 or 8 hp outboard. It has seen as much use as a stand-alone small boat as it has seen for dinghy use over the years. However, I feel it's a bit large for the roof of the 22' when inflated (although I often carry it up there Deflated, without any troubles). For just getting to shore, a smaller or lighter model is just fine. I often carry an inflatable PVC kayak for that purpose, and bring the dinghy only for extended trips where I'll be out for several days or a week and want to do a lot of exploring over long distances.

Regarding durability, my Achilles is a 2003, and our inflatable kayaks were purchased in 2004, all have seen regular use every year since purchase, and have no leaks, patches, or seam issues. Having owned many inflatables over the years, puncturing them has never really been a concern. Then again, with no kids, large dogs, and no crabbing or fishing in them, maybe there's less chance for that type of neglect. Just be careful where you beach them!
 
Mike, What speed do you get with the 9.5' air floor and 6 HP (one and two people?).

The only inflatable I have punctured was the 13' heavy duty Achellies Hypalon. I had a propane tank tied inside, near the boat, and on a several mile ride after filling the tank, the sharp metal on the propane tank "handle" cut into the fabric--it was more of a sawing effect, which I believe broke it down. I have owned inflatables continuously since 1962--56 years...Some got daily hard use.
 
We’ve had four different dingy’s with our 22 CD. Three were RIB & one a motorized kayak & before the C-Dory, we explored some very remote areas in Canada in a 12.5 foot RIB with the only puncture in them all being the Hypalon 12.5 foot having the hard-floor support frame rubbing through on the inside. That is not to imply, I think they won’t puncture or care isn’t needed to prevent it. The other three RIB’s are a West Marine RU 260 8.5 foot, a Saturn Kaboat 12 foot & our present, a Saturn Kaboat heavy duty 13 foot with double protection on bottom. All three of these are PVC. I powered the 8.5 & 12 foot with a 2.5hp 29# Suzuki & the present 13 with the 52# 6 hp Suzuki. My favorite of the dingy RIB’s by far is the present 13 foot. It weighs 80#, but due to its extra length & narrower width it is easier for me to get it back up on the top of the boat cabin by myself, when on the water, then the 8.5 foot 48# West Marine.

This is the Mokai motorized kayak on the boat cabin where it rode during the road trip from Wyoming to Alaska & back in 2010.
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This is the 8.5 foot West Marine in SE Alaska in 2004.
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This is the 12 foot Kaboat on the boat & in the water on Yellowstone
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This is the 13 foot Kaboat on the boat at Yellowstone & in the water at Lake Powell.
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The West Marine 8.5 & Kaboat 12 with 2.5 hp Suzuki about 7 mph.

The 13 foot Kaboat with 6hp Suzuki at Lake Powell. Me alone 13.5 mpg & with us both 10.5 mph
 
One thing about ribs. Some of them will still float fairly well even with deflated tubes. The compartment between the hull and the flat floor (if the boat has one) can provide considerable buoyancy.
 
Jay, Do you really mean RIB (Reinforced (with fiberglass or aluminum bottom) Inflatable Boat. I would classify your boats as "inflatables, with wooden floor" etc. The Ones with wooden or aluminum floors (not bottoms), do have a failure point of the channels or wooden floor boards rubbing on the pontoons.


One thing about ribs. Some of them will still float fairly well even with deflated tubes. The compartment between the hull and the flat floor (if the boat has one) can provide considerable buoyancy.
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The boats with a true deep V and double floor will have some floatation with the tubes deflated, but the smaller ones will have very low freeboard. These are considerably heavier than the ones with a single light floor, and might be too heavy for the roof of a C Dory.
 
We had a zodiac RIB for a while. It had a hard fiberglass, or plastic v-hull. It would not have been suitable for use as a rooftop dinghy IMO. The thing took everything I had to lift the front end up into my pickup and then dead lift the transom and slide it forward. I was younger and in a lot better shape than I am now.

There may be new really light weight RIBS available now that I'm not aware of, but the old rigid inflatables were much heavier than their inflatable and collapsible counterparts.
 
Bob, none of our RIB’s had a hard outside bottom & the only RIB, we had, that had a inner solid hard floor was our 12.5 foot Sea Eagle & it had a rubber inflatable keel & three other inflatable sections with the entire bottom all rubber & sides hypalon. The inside floor was made of an interlocking hard plastic with aluminum support sections on the edge of the plastic, that helped in making the floor more rigid from bow to stern. The aluminum wasn’t smooth where it joined, so with flexing it rubbed a hole through the inside hypalon air tube just as you said was a problem with the design. After the on sight repair on Atlin Lake, I smoothed all edges on the aluminum & also added reinforcing over the air chambers where the aluminum joined. The three RIB’s we have put on the CD22 cabin roof, the 8.5 foot West Marine made by Zodiac had wood slats & though lite, the floor was very unstable, which made it good only for low displacement speed even with motor. The two Saturn Kaboats have a air floor & with 10 psi very hard & stable. We really like the 13 footer. The Kaboats don’t use a regular keel like most inflatables that can run at planning speeds. Instead they have four small hard rubber skegs that give stability at speed & in turns.

I have always described inflatable boats in the short generic form as RIB, meaning to me rubber inflatable boat, of which now the only rubber is for bottom protection on some.

The first photo is making the repair at the 2nd narrows on Atlin Lake & the next is just as we arrived at Haines, Alaska after Launching at Skagway in 2001.
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Jay:
The accepted definition of an RIB is :
A rigid-hulled inflatable boat (RHIB) or rigid-inflatable boat (RIB) is a lightweight but high-performance and high-capacity boat constructed with a solid, shaped hull and flexible tubes at the gunwale.
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The definition of an inflatable boat :
An inflatable boat is a lightweight boat constructed with its sides and bow made of flexible tubes containing pressurised gas. ... The most common term for inflatable boats is "rubber boat" although rubber is usually no longer used in their construction.
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These have been the definitions thru the 55 years I have owned inflatable boats. I do believe it makes a definition.

The first rubber inflatable boat was built in 1845! In 1866 three men crossed the Atlantic in an inflatable boat. The more modern inflatable boat had its origins in 1919, by the builder of airships. The French company became Zodiac and the British company became Avon. WWII popularized life rafts, although they had been used on commercial ships for over a number of years. Both the Allies and Axis used inflatable assault boats during the War.
Several I know, have also shared your enthusiasm for the KaBoat inflatablet.
 
I can’t go back & delete all my post on this thread unrelated to the OP question, so here’s my apology for making them & thanks again Bob for enlightening me on the RIB definition.

Jay
 
Jay, no apologies please! I always like to see your posts. You have had some innovative and very workable roof top dinghies and traveled far and wide with your 22. I hope to follow some of your paths in the future. Always fun to see what you are up to! Keep the posts coming -Phil
 
That is why I love this place so much. Learn something every day. Jay, I learned with you today. Thanks Bob for clearing up my misrepresentation at times too.

Harvey
SleepyC:moon

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Jay, I always enjoy your posts, photos and commentary. Thanks.
Agree no apology. The only reason I mentioned it, is that some may not understand that the conversation was about a hard or rigid bottom, vs a soft or inflatable bottom boat. That the wooden floor boards, are not a rigid hull. (Although the first RIB was a piece of plywood glued to inflatable tubes--didn't work well)
 
Jay, thanks for your posts, it's neat to see all the variations of your dinghies on the roof of the 22. And since the OP is now considering air floor models, all three of yours (Zodiac and 2 Kaboats) are also air floor models and worth consideration.

I too carried a 12' Kaboat on the roof rack for my trip to Desolation Sound last summer. Although it's about the same weight as my Achilles, I actually found the Kaboat quite easy to get on and off the roof, due to its long length and narrow beam, you can really take advantage of that length and get good leverage in getting it up there single-handed. I even mounted the 2.5 Suzuki on the transom once it was up there. With all that weight, I didn't notice any decrease in stability of the C-dory, but I did notice considerable increase in sail area trying to maneuver the docks in a breeze, and in Comox I had to actually spend some time practicing maneuvering in the wind against some buoys in the bay because the boat was handling so much differently around the marinas than what I was used to.

However for dinghy cruising, I found that I prefer the Achilles due to the inflatable keel and V-bottom, it handles some chop pretty well at speed. Whereas the Kaboat with it's surfboard fins and flat bottom really "slaps" over even the smallest waves when at speed. Great row boat though, and I enjoyed rowing the Kaboat for hours until I got tired, then motoring back to the C-Dory.


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