Dinghy Engine Question

[Wildernesstech]

I have rowed to our mooring for the past, before we hit the salt I need to purchase an outboard powered dinghy for out boat. Numerous problems exist:

Our boat is 32.5 Feet so size is an issue.

2.) I currently own a Johnson 9.9 with a 20" shaft so it may be too deep for use with the average inflatable. Can I get by with it or should I sell it and purchase something more appropriate? (It has been very reliable!)

3.) I am leaning toward a 10' inflatable with large tubes that can be deflated and stored on crossings, but will handle fairly rough seas at anchor.

4.) I seem to be questioning my decisions as my experience is limited.

You folks have all been through the process of finding the perfect tender, so please impart your knowledge before I become totally lost.

David

[MMNETSEA]

Hi David,

Our boat is 32.5 Feet so size is an issue. I am leaning toward a 10' inflatable with large tubes that can be deflated and stored on crossings, but will handle fairly rough seas at anchor.

Storage of a 10ft dink can be a problem when rolled up, even if with big lazarettes.

I would 'think' about a 10ft RIB stored upside-down forward of the mast on custom blocks lashed to pad eyes. Lifting it is by using overbuilt halyards on heavy weight sheaves.

I currently own a Johnson 9.9 with a 20" shaft so it may be too deep for use with the average inflatable. Can I get by with it or should I sell it and purchase something more appropriate? (It has been very reliable!)

As it is good , then I would keep it - options then are #1 to raise the transom height of the dinghy so that the cavitation plate is lower than the transom . #2 convert the long shaft to a short 15" shaft . check this site for info :-

click Here

Richard

[JeanneP]

The best dinghy and outboard combination we had was a 9' Achilles with an air floor with a 4 hp Yamaha 2-stroke outboard. We wanted a dinghy that was easy to stow because we never towed it, and lightweight so we could easily carry it up the beach with the outboard on.

The dinghy and outboard's total weight was less than 110# (50 kg)

It's very difficult to find a 2-stroke outboard anymore, so I've done a little comparison shopping for a 4-stroke and dinghy with an eye towards weight.

9.9 hp weight: Johnson: 105# (48 kg); Yamaha: 91# (41 kg); Mercury: 84# (38 kg)

4 hp weight: Johnson - I could not find that Johnson made a 4-stroke 4HP. Yamaha: 48# (22 kg); Mercury: 55# (25 kg) and Mercury makes a 3.5 HP weighing 38# (17 kg).

Dinghies: Inflatable floor, 9', weight ~53# (24 kg), 10', weight approx. 60# (27 kg)

RIB: with fiberglass floor, 9'6", 106# (48 kg)

RIB: 9'1" with aluminum floor, 79# (36 kg) (NOTE: This is an AB RIB, very expensive, and I don't believe they offer the 9' model anymore. The 10'6" model weighs 137# (62 kg).

As you can see, you pay a very large weight premium with the larger outboard and RIB, about 100 pounds of penalty.

My argument for the lighter weight outboard and dinghy. Easier to stow. Easier to carry up the beach. Faster and easier for one or two people to deploy. Far less gasoline needed to be carried. Easier to row when you run out of fuel. And very few places where the extra HP is needed (we only found two, and they weren't places that the average cruising yacht would have found, let alone visited). Any place you visit with more than three feet of tide range will be where you will probably want an easily carried dinghy.

When going from a wood floor inflatable to the air floor, I found the air floor dinghy to be a bit "squirrely", it wasn't as stable when first stepping into it, but once we were settled, it was a comfortable ride.

[Wildernesstech]

I could get used to an air floor as I worked in younger years as a whitewater rafting guide in Colorado. We are currently rowing to the mooring with a 10 foot river raft with a "very" squirrely floor! I'll try to get some pictures early this week to send. I think that when it quits snowing we are going to the boat for a couple of days (before I go crazy). We spent New Years Eve on the boat in the snow and were there as often as possible this winter. It was wonderful! The marina was nearly abandoned and quite peaceful. We found that the boat was easy to heat. And it assured me that Brenda would be comfortable for extended periods on the boat. We were aboard when the current floods affected the water level and awoke one morning to find the shore "much" farther away. The other reason that I tend to aline with your suggestions is because Brenda cannot lift much. My lack of experience has me wondering if you can get a setup as you suggest on plane with two and groceries aboard? Is getting on plane necessary? I understand the need to move sometimes quite a distance due to tidal ranges, so light weight makes sense there. Will the lighter weight work against us in chop and winds? I can't imagine not needing to go to shore in poor weather on some occasions.

David

[JeanneP]

A 4 HP engine isn't very good at getting anything up on plane. One person in the dinghy, no groceries, dead flat calm water and it would plane. Two people, no. We really didn't want to carry enough gasoline to be zooming along, so the 4 HP worked for us.

We once spent more than 8 hours exploring the Rio Colorado in Costa Rica (Golfito area) by dinghy, and we probably used no more than a gallon or two of gasoline. The tank only held about a liter, and we had to carry containers for refills since we had no external gas tank. Interesting trip.

As I said, we found very few places where a slightly larger outboard would have been useful. The portability and fuel economy of the smaller outboard more than made up for the slower speeds. After all, we were cruising by sailboat, how fast did we need to go, anyway?

[sailingfly]

Originally Posted by Wildernesstech

I have rowed to our mooring for the past, before we hit the salt I need to purchase an outboard powered dinghy for out boat. Numerous problems exist:

Our boat is 32.5 Feet so size is an issue.

2.) I currently own a Johnson 9.9 with a 20" shaft so it may be too deep for use with the average inflatable. Can I get by with it or should I sell it and purchase something more appropriate? (It has been very reliable!)

3.) I am leaning toward a 10' inflatable with large tubes that can be deflated and stored on crossings, but will handle fairly rough seas at anchor.

4.) I seem to be questioning my decisions as my experience is limited.

You folks have all been through the process of finding the perfect tender, so please impart your knowledge before I become totally lost.

David

[MMNETSEA]

Hi Sailingfly,

Nothing was posted - welcome -- have another go.