Towing A Large Dinghy Questions

N

Newtugnut

Well-known member
Joined
Feb 14, 2012
Messages
73
Fluid Motion Model
C-24 C
Vessel Name
"Blue Horizons" R31
MMSI Number
316023141
FYI: we are soon "new to be Ranger 31 owners" and have some questions regarding towing a large aluminum hulled RIB dinghy. To put some perspective to the question, in our 30 years of boating in the Pacific Northwest we have always towed.

Our latest towing effort is an 11' 11" aluminum RIB being towed by a 36 ft sailboat - total weight for engine and dinghy about 220 lbs. Towing speed is about 6 knots. Note dinghy speed when using the dinghy with 20 hp motor can be 20 knots with two people. Bow tends to ride high when towing. 20 HP Outboard motor permanently on back of dinghy. (leg raised when towing).

Towing harness is the usual Y bridal at both the boat end and the dinghy end with a single line in between.

So ... we are not new to towing and all the regular issues that entails (BUT COMPLETELY new to Ranger Tugs -power boats in general for that matter) and the higher crusing speed.

TWO QUESTIONS

1./ Experiences towing a dinghy at say 16 knots

2./ For those Rangers with the outboard Railing option for the swim grid, any problem with the Y bridal wearing or causing strain on the outdoor swim grid station posts? Informal discussions with Factory suggests not a problem but wanted to ask about user experiences.

Thanks a million

PS One thing that comes to mind, is a slight loss in crusing speed and having to up the engine RPM a bit to compensate.

Newtugnut
 
Welcome to the Ranger Family. I am very envious of you new boat but we do love our R29. When Nita and I bought our boat we had a 13' Boston Whaler with a 40hp outboard. We found that our boat had such a large wake that it was not comfortable for us to tow the Whaler at any kind of speed. We elected to sell it (Andrew @ Ranger bought it from us) and go with an inflatable dingy which we could carry on the transom step. When you get your new boat you might give it a try but I think the wake will be too much for towing (the wake could be different on the R31). But the decision should be based upon your comfort level and not on mine.
Bob
 
Towing a 220 pound ramming device at 16 knots will be interesting when you have to stop or swerve suddenly...
 
We have towed in the past, but vastly prefer mounting on the swim step. With non-RIB inflatables, towing is a little less iffy because they seem to slow down well and are less prone to bumping the towing boat. But RIBs and solid boats like Whalers are nice and smooth on the bottom, and lose their energy slowly.

At the increased speeds you will be looking at with the Ranger, you will likely need a much longer tow rope than you are used to with the 36 sailboat - I would guess at least double. You have to get it well in back of the Ranger so it won't surf down the front of the 31's wake (or surf down the face of a large wave in heavy weather/following seas) and whack your stern. Someone will have to man that rope when changing speeds, to adjust for the best towing position. This longer tow rope can also cause things to get interesting if you get into rough weather - you can actually find your dinghy in a different wave trough than your Ranger, with the rope dipping through the wave

Quick question on weight. 220 pounds seems extraordinarily light for a 12 foot RIB dinghy with a 20HP motor on it. I've rarely seen a 20HP motor alone under 100 pounds (the current Merc and Johnson models shows as 115 lbs dry weight). Then add in 40-60 pounds for fuel/tank and other equipment, and you are at 160-170 pounds before you even include the boat. I would hazard a guess that your real-world towed weight is closer to 400 lbs, which as Levitation points out is an awful lot of weight to have barreling down on you when you have to emergency-stop from 16 knots.

No direct experience with the swimstep rails on a Ranger, but I would have to image that the rails would mildly complicate any towing situation, since you would have to work around them to deploy the harness and change the tow line length when coming in to the dock.

I towed for 2 years (10 ft inflatable with 5 HP motor), but eventually found that davit mounting was, overall, more convenient than the fuss of towing.

Congratulations on your pending purchase - I am beyond envious 🙂
 
Thanks to all for the replies! Just to respond regarding the weight question, we may have told a "lie". The Honda 20 hp comes out at 114 lbs (recollection), dinghy at 110 (also recollection), uni helm 50 lbs, weight of battery (reg car battery size 40 lbs ?), fuel tank (20 lbs?).

Okay this puts us at 344 lbs (if the math is right)

Based on what everyone has said, experience will tell. Presently we have a Factory option for a davit arm system with lifting winch and a RIB dingy to consider. It looks like a neat system.

From my limited reading of Tugnuts, stowing a dinghy on the transom with a simple lifting system seems to be the norm.

SO HERE IS THE NEXT BIG QUESTION Size of outboard motors that people are mounting on the transom?

When you get to 5 hp and above the weight is too heavy for me without a lifting crane. Plus

With a 5 + hp outboard, lifting crane, barbeque hanging over the swim grid, space for the crane plus shore line drum when we cruise to DEsolation. THAT's alot of stuff on or around the swim grid.

Perhaps a simple 2 hp motor (motorized rowing) is the way to go.
 
We have towed a 10' RIB with 20hp. Honda for about 250 hours with our Ranger 29. Using about a 50' tow line with transom bridle. Up to about 10-12 knots this has posed no problem depending on wind conditions. Above that speed dinghy begins to girate and become airborne. Longer tow line might help but haven't really cared to go faster for any length of time while towing. Otherwise, we bring dinghy up on davit. (see Zuma pictures in owners album). Our Walker Bay with gear weighs about 365 lbs. We have no transom rails.

Nice thing about towing, as you know, is that the dinghy is instantly available for emergencies and short pit stopsl

Congratulations on your new boat and welcome.
 
Although we only have an R25 🙁 , we tried towing also and had issues with the size of the wake. In addition, fuel consumption was much higher. We installed davits on the swim platform and our dinghy rides there. We can drop it when we get to our destination in less then 5 minutes (including motor installation).
 
Consider towing most of the time with the transom/platform mount as a backup. We had an inflatable invert in a norther coming in to Clearwater from Pensacola as a wind/wave combination got hold of it after 270 miles in The Gulf. I can assure you that they make wonderful drogues! I can also assure you that after 50+ hours of high winds and following seas, righting it was no picnic. Two tired people on board and still in pretty messy weather. I did have the foresight to stow the engine before departing or I would have ruined it.
 
Thanks again to all for the interest in this topic. To respond to ZUMA I looked at your pics (nice shots!). Its what I was concerned about, at higher speeds the dinghy becvomes unstable.

Your dinghy is 'equivalent' to ours in terms of size and weight. You also mentioned that you have davit arms.

So, you have the best of both worlds (either tow at modest speeds) or mount on davit arms if say desiring to make a fast passage.

Could you provide any details on the davit arms? Is the dinghy flat with the O/B or on its side with a tilt plate. It seems lile a lot of weight/strain on the back end but I am sure you thought it through.

Did you do this as a factory option or aftermarket?

It seems to me, mounting a large dinghy like would mean forgoing the "porch railing" on the transome.

Again what I like is that you have the best of both worlds.


PS Thanks again to all that replied. It's these user groups that keep the interest really going in boating (among other things). Particularly when making such a drastic step as moving frm sail to power after 30 years.

I am sure when we make our final decisions looking back none of this will have seemed like a big deal. However, seeking the experience of others wo have gone down this road already seems prudent


TNX
 
Our davits were built by Ollson Mfg. of Seattle (boatdavit.com) and is the RS-5 model; 500 lbs. capacity. The dinghy remains right side up and the engine mount is conventional. The installation was made at the factory and some reinforcement was added to the transom. I don't think any changes were made to the swim platform but Howard at the factory would remember.

The nice thing about the upright positioning is that light weight items like extra life jackets or a crab pot or two can be thrown in the dinghy while underway. And, a stern line rope reel can be attached between the davit arms underneath the mechanism. Also makes a handy drying post for wet clothes and a very good hand hold when entering the dinghy. Also doubles as a crab pot puller with addition of a clip-on sheave.

All mounting choices are a compromise, but this installation has been a good solution for carrying a heavier dinghy; and it allows us to carry the dinghy while trailering short distances. Probably would carry on pickup for long trips; but one can just back the pickup under the transom and lower the dinghy on to the top of the truck bed.

Happy cruising.
 
Thanks Zuma for the detailed report. I think this is the solution we are looking for.

I would like to converse privately by phone and or email if that/s okay with you.

My email is plumptre@hotmail.com

TNX
 
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