Auxiliary outboard on R-25

[Ram]

I know there's been some discussion in the past of mounting brackets for trolling motors, but I didn't see anything specific to motor size. I'm thinking to put an outboard on as a backup (the previous owner had installed a bracket that attaches to the hull and extends out to the back of the swim platform). This is only an emergency backup for us as an extra safety margin, as we are cruising in areas where we have little chance of getting any immediate aid or of getting parts if there were any major problems with the diesel. My question for those who have kickers is, how much horsepower does it actually take to push the R-25 to hull speed.

I have a Yamaha 9.9 high-thrust on my Flicka sailboat, which weighs at least a thousand punds more than the R-25, and it easily drives the boat to over 6 knots, which is actually above the theoretical hull speed. I know people who use 5, 6 and 8 HP outboards on the Flicka and are quite happy with them. My preference is to get the lightest motor possible that will get the R-25 up to about 6 knots for emergency backup. I'm wondering if one of the newer 6 HP 4-strokes, which only weigh about 60 lbs. compared to nearly 100 for my Yamaha 9.9, would get it there.

Any specific experience related to this? Also, what about shaft length? My engine bracket is pretty low to the water, and I'm thnking I could get by with a 15" shaft, but I don't want to overdo it.

 

[CaptMac]

Sorry for the delay - I wanted to collect some data from my boat first from some tests I ran years ago on Island Ranger (my R-25), and since we went cruising to Edmonds for lunch today (just delightful!), I was able to get it -

I mounted a Honda 9.9 (over 100#) on a bracket mounted on the swim step. I'm pretty sure there are pictures in my album. At maximum rpm, I was moving Island Ranger at 3.7 kts or so. I also tried my Honda 2.0 hp - and was able to move at 2 kts. The conditions were relatively calm......

The ease of moving a displacement hull thru the water - yes, a low hp will work. But a semi planning hull - takes a bit more. And if it happens, I'd bet it will not be calm waters when you are trying to get home.....

We've chosen not to carry the spare motor when cruising. I decided that the reliability of the diesel, and the ease of repairs worked for me. And yes, I carry an Epirb, and a handheld VHF if all else fails,...

Mac

 

[Commander Ed]

I have just put a bracket onto my swimstep of Sea Dragon (R-25) It has a quick disconnect and I can go from nothing to an outboard mounted in about 2 minutes. Not much experience, but I did put my 4 HP 2 cycle (about 40 lbs) on the bracket and try it out in calm water. It pushed Sea Dragon along at 4.5 kts. Not bad for a small engine, and since it is a 2 stroke and can rotate up - I can actually have the outboard "live" on the swim step if I wanted. The rudder worked fine, but I have not tried steering with the outboard yet. I will be taking pictures of the setup in the next few days, and I will be going to the Seattle Boat show this weekend if anyone there wants to see. (I will also post them here on the site) So far so good for my attempt to have a "get home motor" available. Seems to me that you get about a knot / 1 HP from the other responses you have received, and I am right in line with that observed data.

 

[j&lgray]

For the Laurie Ann, we put a 6 HP, 4-stroke on a swing mount that is attached to our dinghy. Because 4-strokes like to stay vertical due to the oil pan (yes, you can lay it on one-side only but that often does not work out) the swing mount keeps the engine vertical when the dinghy is tilted up on the swim step and then swings down to match up with the dinghy's transom. In our solution, the motor stays on the dinghy and if it is needed for a backup for the mother tug, then we put the dinghy against the side of the tug and use the dinghy (yes, you guessed it) as mini-tug, pushing the mother tug. We have tried this out, deploys quickly and efficiently but the max speed with the tug's hull is about 4 knots.

We went this route because, frankly it was easier, simpler and and quicker to do this rather than moving a motor into place on the swim step. We also use the dinghy and motor package as a taxi when we are at anchor or on a mooring buoy.

We are with Mac's theme, the reliability of the Yanmar is wonderful. The Laurie Ann has nearly 3,000 miles under her without a problem with the engine while underway. We also have a backup handheld VHF and two complete anchoring systems.

The most common reason why a diesel will stop is dirty fuel. Unlike gasoline that will function with some water and a whole of junk in it, diesel must be very, very pure. 30 minutes of preventative maintenance once a year by changing out those fuel filters will give you a wonderful piece of mind.

 

[Stella Maris]

When we had our Catalina 25, we would use our inflatable in the same fashion John has describe. It worked great to move Tenacity along. Fortunately we only had to do this twice in a pinch.... Amazing thing was, we did not have a diesel on Tenacity, we had a four stroke Yamaha......

 

[Ram]

All good comments and food for thought.

I wish I could say the same about diesel reliability, but on our first extended cruise last summer we had major issues with the Yanmar.

First of all, we somehow got an extremey dirty load of fuel, and just prior to the cruise I had replaced the filter and installed a primary (which our boat didn't originally have). This clogged 4 times in the course of 2 weeks (I was fortunate to be able to find a couple of places to load up on filters), once when we were in a somewhat touchy sea condition.

On top of all that, we had a water hose spring a leak onto the exhaust manifold, sending up a cloud of steam that made us think the engine was on fire. We had to get a tow frpm the CG as we were in the middle of the Strait of Georgia.

Oh, and did I mention that right after we bought the boat (used) the shaft linkage disconnected itself from the gearbox? Or that when I hauled the boat just prior to the cruise there was no nut on the end of the prop shaft? Or that the thrusters stopped working a couple of times because the battery connections came loose? Or that the GPS stopped working at all because the antenna crapped out?

I hope at this point I have worked out all the kinks and we will have a good season ahead of 100% reliability, but past experience has warned me not to be overly optimistic.

 

[Levitation]

Dirty fuel is not an engine reliability issue - the engine is innocent... Best is to use a funnel with a fine screen which allows you to notice the clarity and condition of the fuel as you fuel up... A square of a worn out, white tee shirt, draped over the funnel works really well for instantly seeing bad stuff in the fuel...
On the water hose leaking - did the hose perforate, or was it a clamp problem?
Your other issues, are/were the hazard of buying a used boat / truck / whatever... (as opposed to the hazard of buying a new boat)
My used R-25 was just ten months old and we used it for 6 weeks before hauling for the winter... In that short time we had the battery charger go west and found corroding clamps on the batteries, and the anchor roller was shedding bolts, etc... And I have found other issues while currently doing preventative maintenance on it in preparation for next season...
So basically, "welcome to the club"... Boating is the art of doing repairs in new and exotic locales...

denny-o