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Senior Member
Oct 2, 2007
Where is the dinghy section?*I am sure a few more people that* have dinghys with questions or topics. Who knows we might find some other people that have RIBs set up to run 35 MPH. :)
speaking of dinghys, has anyone added one of those after-market fins or half tunnels to their dinghy motor? are they any use at all?
they will help you get on plane faster or with a heavy load but they do produce more drag and slow you down a little.
the only thing it has improved for me is getting on plane, i have used GPS with and without a fin and the fin slowed me down 1-2 mph
We presently have an Apex Rib with a 5hp Honda for the upcoming delivery of new boat. We have had this for 10yrs, and not used for the past 6 ( hanging in basement ) waiting for proper use. Everything in great shape, but are going to look at Ribs and dinks that have a complete steering system at boat show tomorrow.
Anyone use this type ( center console with wheel ) type, and I need to stay under 850lb. for davit. I'm not that interested about going fast, just point A to B.
My 9.5' AB RIB with a 15hp Yamaha 4 stroke with one person aboard will almost do a back flip if you goose it without the Dole Fin. With it, it comes up on plane in an almost level fashion and flies. I have never noticed any reduction of top end speed.
I have had a 10' Bullfrog for the last three years. I love the boat. It's virtually indestructable. Aluminum Hull, Hard Polyethelene tubes. The manufacturer convinced me to install fins on my 15hp Honda to speed the planing process. It really does help. As to speed loss, I imagine there is some. I also had a custom eleven gallon seat/fuel tank installed in the forward position. That also aids in the planing process having the extra weight, as well as getting the tank out of the way.

-- Edited by Carey at 11:29, 2007-10-10
I'm with Carey on the Bullfrog. We replaced our Avon w/ one of the 11.5' Yacht Tenders. It catches fish, crabs and prawns - the blood and guts wash off, it is stable when hauling pots, tows easily, can be beached on shells and rocks, we love it! But it is heavy and causes a noticeable list when hauling to the upper deck of our Krogen. You'll need a good davit system.
Doc wrote:

My 9.5' AB RIB with a 15hp Yamaha 4 stroke with one person aboard will almost do a back flip if you goose it without the Dole Fin. With it, it comes up on plane in an almost level fashion and flies. I have never noticed any reduction of top end speed.
Doc, I have the exact same dinghy with a 15hp Merc.* I agree.* The fin is a basic necessity.* The first time I put my dinghy in the water I was very disappointed because it was soooo o squirrelly.* I put a fin on it and it is tame and level and rides quite nicely.* I highly recommend a fin to anyone who is having problems getting on plane in a stable fashion.
FYI - Anyone considering an aluminum dinghy such as Duroboat, and intending to hang it on stern davits or swim step, would be advised to determine the alloy of aluminum used on that boat. Many manufacturers use 5052 alloy as it is cheaper and more bendable, but it is also much more prone to disintegration when exposed to a combination of salt water and diesel exhaust combined. The acidic nature of this combination ate the bottom out of my Duroboat in two years when hung upright about three feet above the exhaust. It took me several months to convince Duroboat's owner that they were responsible since they had advertised it as a tender. Always choose 6086 as the preferred marine alloy. My current Bullfrog has 6086, and three years shows no signs of trouble.
My oldest son bought us*a 12 ft livingston, center consol, 25 house with a 4 hp kicker on a treailer for father day.* Its a very stable durable boat with good capacity.* The summer I polished/varnish the Eagle standin on the gunnel with very little tipping.* Great dink for running around and tough enough to beach.

We also have a 12 ft sailing dink that the grand children have beat/used for 12 years and a 19 ft run about with 140 ho Merc*that we have had for 38 years and still going strong that we tow.

Here is the 15ft aluminum dink w/25 hp. Planes easily with many full grown guys and also rows nicely by oar.
<q>Always choose 6086 as the preferred marine alloy.</q>
I think you mean 5086 -- there is no 6086 alloy.* 5086 is the best marine grade alloy for corrosion resistance, although 6061 is also good and is commonly used for extruded members.
We have one of those dinghys set up to run at 35 MPH. It is a Caribe 12' with a Honda 40 HP. We had some problems with bow lift and getting it on plane but after installing a horizontal fin on the engine, that problem was solved. It was also much cheaper then "smart tabs".

We also can anchor out in further locations and still visit various marina with little or no cost.
Plus it's fun to run around in.

Because of the info I got here I just put a Davis Hydrofoil on our 9.6 Caribe. It has a 15 hp Yamaha 2 stroke. Wow, what a difference. It gets up on plane almost immediately, it is not squirly at high speeds, and the thing my wife really likes, it doesn't porpoise like it used to in the least amout of chop. I had recently checked my top speed with my hand held GPS and like others mentioned I lost a couple of MPH at top end from 25-26 to 23-24.
Not a big deal at all compared to the other benefits.

Thanks guys!!
Doug has an AB310 with a Nissan 25hp. In his endless quest for more speed(I believe he is trying to compensate for a shortcoming elsewhere), he refuses to put a fin on his motor saying it will add drag and loss of speed. I have seen him almost die many times due to squirrelyness at high speeds...
***** We have a 12' Caribe RIB, 30HP Honda, center console.* It has internal fuel tank, nav lites, bildge pump, power tilt & trim, bimini top, horn, and full guages including trim, speed and fuel quantity.* It is a mini boat that is Dol Fin equiped and is capable of 30MPH.* Weights in at under 400lbs and is a blast to opperate.
Anyone care to comment about beaching fiberglass bottomed RIBs? My previous RIB had an aluminum bottom and stood up to my abuse very well.

The RIB in question is a 11.6 Caribe.
I have a 9.6 Caribe I have beached it a lot in soft sand etc. But would not do so in coral or a rocky area. The bottom fiberglass is less that 1/8" thick. I was going to fix a small crack in mine one time. I started to dish grind the crack in prep for fiberglass and was instantly through the bottom. Totally surprised in how thin the material was. As part of the job I added another layer of glass with epoxy down the center about 3" on either side of the "v" to give it a little more thickness.

In an area with a rough or unknown bottom I generally stop in about a foot of water, get out and put down the anchor with a short rode. We keep water shoes in the dink just for this situation.
Jim, I am willing to bet they just screwed up on during the layup of your boat. I store my AB up on a dinghy dock and I HIT it at about 5mph every time I go up on it. I would think I would have beaten it to pieces by now if it was paper thin. ANyway, We all know fiberglass layup is far from perfect....especially as it applies to dinghies.
John, I'm interested to read that you store your RIB on a dinghy dock. Is that one of those floating pontoons? You keep it right alongside Flyin' Low? Thenm what do you do? Tow it?

I've just*bought the 10' AB with alu hull and plan to pick up a 15hp 2-stroke Merc this weekend. Still figuring out what to do with regards to davits but am pretty much decided I will get the removable St. Croix davits. In the meantime, I will learn to carefully*tow the RIB and will store it in a local boat yard.

Always keen to hear how other people do it.

Mark, that is a great question. We used to have a slow boat and we would tow it. But when we got this boat, we were hesitant to tow it at 15kts so we just didn't bring it on the first few trips since all of our friends are dinghy freaks and the dinghy ratio was damn near 1 to 1. Anyway, I got sick of not having my dinghy so I was gonna tow it dammit. As long as you get it centered on the wake and far enough back, it does just fine. Far enough back is about 60ft....on the backside of the bow wave hump and in between the next hump.....if that makes any sense. We have towed it like this in very choppy conditions and it seems to do just fine. I always keep a close eye on it but as long as none of the motions are "irregular" it takes to the rhythm of things. One motion that would be considered "irregular" would be a big wake from a passing boat....anything that upsets the mothership mmight upset the tender. Other than that, no regrets.
Thanks John. I will be towing for the first time tomorrow. Wish me luck!

Here in HK, I am forever surrounded, overtaken and cut up by Azimuts, Sunseekers and other fast, big boats and their obnoxiously big wakes... Aaarrrggh! So I will need to be extra careful. I drive very defensively anyway because my 34' hull doesn't take kindly to big wakes coming in from the beam or behind, so what I do for the big boat will be good for the little boat too.

Turns out that the cheapest way to get my new davits from the US is by Fedex (Hmmm?), which means I might have some removable davits fitted and operational sooner than I had expected. I don't plan to tow for more than the next few weekends. Let's hope the davits turn out to be everything I expect them to be.
I installed a Weaver snap davit system several months back. I went with the arch on the transom. We have a Zodiac 340, weight about 170 #'s!!. This thing is so hard to tip up that we tended to leave it down. The davits make installation of the motor easy. After once or twice towing her at about 12' back I was hooked. I keep the engine on- tipped up while towing. When backing out of the slip I pull the dink up tight with the extra tow line attached to the SP boarding ladder. I just use a West Marine Velcro strap till we are heading out. When docking I do nothing. No problems in 6 months.
Boogie, how did it go???* Here is a pic of my dink on Galveston Bay doing about 15kts.* Dunno if you can tell but the wind is about 20kts and pretty damn choppy!


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My first attempt at towing went well. At higher speeds (say 10-13 kts) the RIB was evidently on the downslope of the first (second?)*hump (which wasn't even that big) so I think I need to lengthen the tow line by about 20 feet. The RIB remained unruffled at all times, but conditions where only slightly choppy and poor weather kept the big wake-makers at home.

Single-handedly managing the RIB in close quarters needed some planning, but will no doubt get easier with practice. Whilst maneouvring out of the mooring and out of the marina, I had the RIB tied alongside Beluga*with*the RIB's*bow line attached to my midships cleat, and a stern line up to my aft quarter cleat. All worked fine.

Coming back into the marina at the end of the day, I*figured I'd just tow the RIB in normally*but with a much shortened line. That worked perfectly, and the wife didn't even need to fend off the RIB when I got into my mooring.

So, like Steve, I suspect I could get used to this very easily. Nevertheless, I look forward to installing and using the removeable davits when they arrive. Will keep you posted!

Here's a photo (taken with cellphone on a dull, damp day)

-- Edited by boogiediver at 08:03, 2009-03-11


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Mark, I see you took part of the advise and bought a 2 stroke 15hp and horizontal davits taking the weight off the tubes.* Watch the flexing of the transom with the dink full.** The majority of the leaks are way back by the transom that you can not repair with out taking the tube off.* You might still think about buying a small light weight engine for those occasions you just want to putz.

Thanks Phil. Yes I did. I know you're not mad about RIBs, but this one really suits my purpose well (I think) and I had in any case put my money down! The engine was a tougher decision but 2-stroke did indeed seem the way to go for now. Especially because I wanted a big more kick in a smaller/lighter package.

Experience last weekend shows that a heavier engine would have made it EVEN more difficult to back the RIB off the beach! How to people deal with that? Roll the RIB up and down the beach on blow-up sausages?
Great to hear it went well. I have the EXACT same dinghy as you(except mine is glass...not Al)
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