Dinghy Questions for Cat Owners

[muskoka]

We've just bought a new cat and the space between hulls at the davits is 3.4m / 11'-2" clear at the narrowest point.

What is the longest dinghy you would put in that space? Is there any rule of thumb regarding clearance for the dink?

Thanks

[maxingout]

I would not worry about the horizontal clearance. It's the vertical clearance and overall dinghy weight that concerns me.

We have sailed plenty of miles with our dinghy in our davits, and we always secured the dinghy by its bow and stern using additional lashings so that it wouldn't swing to port and starboard while we were sailing. Very light lashings do the job nicely.

When we sailed on offshore passages, we always took our dinghy off the davits so that there would not be a problem if conditions became rough. We never had any problem with our davits or dinghy during our cirucmnavigation or during the thirteen years that we have had the boat.

We have known boats that had their davits broken or ripped off the boat when the dinghy was hanging on the davits in rough seas.

Cheers,

[GordMay]

The rule of thumb, I’ve always used, is:
The dink’s LOA shall not exceed the mother-ship’s Beam.

[Sunspot Baby]

Gord's rule might be great for a monohull, but I doubt cat owners need dinghies that long.

As to Maxinout's concerns, I consider davits for ease of launch and retrieval but don't want to be out in big stuff with the dink hanging there. For major passages, it should be deflated and/or stowed on deck.

There is more to consider than space available, but a 10' dink seems about the norm for most cruisers. It depends on what you do. Some real cruisers have small dinks they row. Some have big go-fast types. If you are going to be SCUBA diving 4 people from the dink, need more. If you are just shuttling you and the Admiral a hundred yards, then small.

You can see our dink and davits in my picture gallery.

George

[Yotboss]

When chosing a tender, we considered weight, stowability and performance, pretty much in that order. We ended up with an 11 footer and opted for hanging it from an arch rather than davits. That get's it up there above our bridge deck clearance. Also, the longer length allows it to wedge itself in the arch so it's really rigid when tied off (that was a pleasant accident). The whole combination has worked really well for us so far.

[Ativa]

On my cat storage below deck for the digny was important for me as I tend to sail and travel a lot. I bought the ten foot pota-bote with a 5 horse motor. The boat is always much better with two people on board easily stored on davits with custom bridal and folds up and goes below decks when we take off for a few days from the boat. Ten foot is just great for supplies and two people.

[cchesley]

I concur with Gord's post. The dinghy length should not exceed the boat's beam! Currently, I'm carrying an 18' tandem sliding seat pulling boat and towing my 11' inflatable. Towing is unpleasant after a year of carrying the inflatable... but I just really wanted that sliding seat boat too. It does not make a good dinghy but for excercise it's great. I'm currently considering the option of stacking the inflatable RIB & outboard OVER the pulling boat.

My dinghy stowage consists of using a boom extension to pick and launch the dinghy off stern chocks attached to my 'back porch'. It's far superior to davits as it offers secure, lashable stowage. No sliding and chafing dinghy that can never be properly snugged up under the davits. I am considering some additional fold out arms/chocks that will permit the stacking. I've also considered davits for the 18'er so it can be mounted aft of the inflatable in chocks. The boat can handle the weight aft as it currently floats in a slight bow down aspect according to my eye. The extra 50-200 lbs aft won't be an issue but will extend my LOA a couple more feet thus upping my overnight costs at a dock.

It's a bit of a pain to deal with two small boats when the one you want needs to have the other one moved first but worth the overall effort. Stacking the RIB over the pulling boat allows access to the 'work boat' easily when needed.

The biggest issues in the current mode is that leaving a dinghy in the water for an extended period of time will create growth issues. I'm currently swapping the boats out when I'm in one spot for a few days so that the growth process has to 'restart'. No problem yet here in the PNW with 10 consecutive days in the water for the RIB.

[schoonerdog]

As others have mentioned, cats should avoid having a lot of weight in the forward or aft 1/3rd. Look at the AB aluminum if you're buying from scratch. You can get a light weight, very nice boat that will take a good outboard. As others have mentioned, at 10 ft you have a boat that will carry 5 people and carry a nice 15-20 HP engine.

[muskoka]

Thanks for the info everyone!

We're looking at a Walker Bay hard bottomed RIB (10') with a 10hp engine. That looks like it'll fit nicely in the davits and at 127lbs (57kg) it's fairly light. The davits were rated up to 200kg!!!

[fastcat435]

Originally Posted by muskoka

We've just bought a new cat and the space between hulls at the davits is 3.4m / 11'-2" clear at the narrowest point.

What is the longest dinghy you would put in that space? Is there any rule of thumb regarding clearance for the dink?

Thanks

I think I would place a dinghy of 3.40 meters long so you do not have the swing of the dinghy , take a lightweight one like the African Lite , only 25 kilo,s or 55 lbs build in epoxy and hypalon .

[fastcat435]

African Cats: comfortable lightweight performance leisure catamarans

[Tropic Cat]

I removed the davits on our boat. The davits weighed about 40 lbs apiece and with the dinghy weight added the boat did not feel right under sail and really squatted under power (twin diesels). Mine is one of the smallest cruising cats made and perhaps size does in fact matter (sigh)

[muskoka]

Rick,

We have concerns about the weight as well. We've decided upon the 3.1m (10' 2") dink - it weighs 58 kg (127 lbs) which is a mere 5 kg (11 lbs) over the 2.7m.

The big dilemma is the outboard -
1. 15 hp 2-stroke = 41 kg
2. 10 hp 4-stroke = 42 kg
3. 8 hp 2-stroke = 26 kg

Environmentally, the choice is #2. Fun wise it's #1 and weight wise it's #3. All have pretty good reasons to jump to the forefront, but it's really between 1 & 2. I suspect the price of the 4-stroke will push me to select 1.

So, I'll have about 100kg cantilevered off the back of the boat. I'd guess 100kg back there is like having an extra 3 people in the cockpit due to the cantilever. As she's a decent size, I'm don't think she'll squat and FP said the davit capacity is 200kg.

And for offshore passages, we'll deflate & stow aboard.

Cheers.

[Factor]

Originally Posted by muskoka

The big dilemma is the outboard -
1. 15 hp 2-stroke = 41 kg
2. 10 hp 4-stroke = 42 kg
3. 8 hp 2-stroke = 26 kg
.

One thing to remember is that you will have to carry more fuel for the 2 strokes and that reduces some of the advantage of their lighter weight. I have a 15 hp 2 stroke on the back of the tri, all other things being equal it uses twice as much as 10 hp 4 stroke would so I have to carry twice as much fuel at nearly 1kg per litre. It becomes an issue on longer coastal trips.

[Strygaldwir]

11.5 feet. It really does matter how much space is between the hulls. If you have davits, you can go a little wider, but really not much need to go much larger.