Tender outboard - how big?

[Guest]

I am thinking of buying an inflatable dinghy and outboard engine but would welcome any suggestions as to the appropriate engine power.

Useage will be as a yacht tender, including afternoons exploring creeks etc.

I was thinking of buying a dinghy in the region of 2.7m to 3.1m in length, most of the manufacturers brochures indicate maximum power of 10-15HP at this size but I guess that is overkill for my purposes.

Is there any merit in getting something big by dinghy standards, say 15HP, with the intention of it doubling as an auxiliary for the yacht should the main engine pack up - or am I living in fantasy land - would a 15HP engine move a 8 ton yacht in anything other than mill pond conditions?

 

[Guest]

Most people only need a 2.5 outboard for a tender of around 2 - 2.5 length. If you get bigger the real problem will be weight and size. Just think of you being sat in a small dinghy in a bumpy harbour trying to handle an engine that weifgs a lot.....in the water it goes.

I would go for something small rather than big..maybe a 3.5

 

[Guest]

Well, 15hp would be interesting!

However, it is perhaps a shade too powerful for the average tender! When you think about it, all you are doing is going from the shore to your mooring and back again, and really 2.5 - 3.5hp is more than adequate for such a task. As to the ability of a 15hp outboard to push an 8 ton yacht I would imagine you would have very few problems! I have seen a Thames Sailing Barge being towed against the tide by its dinghy powered by a Seagull Silver Century outboard!

 

[ChrisJ]

Re: Well, 15hp would be interesting!

I agree with the "small is better" in this case.

If it is too large, then getting it on and off the dinghy is a right pain. 2.5HP is about as big as one person can manage from a dinghy up onto the pushpit of a yacht. Anything bigger requires clever ropes or a willing helper.

If it is too big, then the noise will startle anything in the creeks you are wanting to explore. Most creeks I come across in the dinghy require very slow exploration in order to identify where the water is 6" deep, as opposed to 1" deep and 5" of mud.

Any size is less work than rowing, and quicker once the outboard is attached - although if it is very small you still need to get to the side when going against the tide.

Cheers, Chris

 

[Guest]

To plane or not to plane

As most of the replies suggest, small and light is probably best. I have used a Mariner 2hp with a Bombard AX3 for years and it's fine. (I also have an AX2 but I reckon it's just too small). BUT - I've always been envious of those with tenders that can plane!! It allows them to anchor further away from the crowd and opens up their horizens for exploring etc. Of course you have to consider the extra weight and handling. For an outboard that will be powerful enough to make your dinghy plane you will almost certainly need some form of lifting device to get it on and off the inflatable. and what about the weight of the beast on your pushpit? The inflatable itself must also be considered if you want to plane, and if I were buying new I would almost certainly go for one with a rigid inflatable floor. I was very impressed with the Lodestar range when I saw them at the boat show.

As far as your tender outboard acting as a get you home in an emergency - yes, not a bad idea. Last summer I was bringing my boat back from the Med through the French canals when the diesel inboard siezed. I had to buy an outboard to fit to the transom (boarding ladder) to complete the journey. I bought a 9.9 Yamaha 4-stroke short shaft and it worked very well. The boat is 35' and about 7.5 tons. When I bought the outboard I had in mind keeping it for the tender of new boat for the reasons outlined above. But I have yet to convince myself that it is practical (Yamaha 9.9 4-stroke weighs in at 45 kilos!!).

I think it comes down to planing or non-planing. I can't see much point in going for anything bigger than 2hp if you settle for non planing. But if you want to plane then you will need an inflatable with a planing hull and an outboard with enough power to get at least two adults and some shopping up onto the plane. ( don't forget that big outboards have separate fuel tanks).

 

[Guest]

You don't want a motor any bigger than your dinghy can handle. That in turn is determined not only by the size of the dinghy, but how rigid the floor is, and to a lesser extent, how pumped up the side chambers are. A soft dinghy with a soft floor will start to "fold" rather rapidly as the the motor power and speed increases beyond the safe limit. Add a rigid floor, and the safe motor power (and speed) can increase considerably. Difficult to give hard and fast rules - best to look around at what others do and ask their advice, or if possible, try the dinghy (and floor) your thinking of buying with several motors, checking the weights involved at the same time. My own experience is with an Avon Rover 2.81, inflatable rigid floor (which is essential for our golden retriever) and a Mariner 3.3. Dinghy could not handle much more power, I couldn't handle more weight (originally bought a Mariner 4, but took it back immediately - too heavy).

 

[Guest]

Many thanks for all your helpful comments.

I think I will err on the side of caution and not risk giving myself a hernia.

Regards

Matt

 

[robp]

Re: To plane or not to plane

Dudley, all the postings are obviously sensible re the weight etc. I went the planing route that you mention though. This was largely to enable the kids to have fun when they were younger. (Also me - and it is efficient)! A 5HP Selva and the Lodestar you mention. The 5HP is just about manageable by me alone but not in a chop. I put a line around the handle if I'm nervous of dropping it. Re The Lodestar; I too was impressed at a show and changed from a Typhoon 2.7 with wooden deck. Although the Lodestar 2.6 is well made, it is very small inside by comparison and I am extremely dissapointed that the seat completely delaminated in less than a season, just on the pontoon.

Rob

 

[Guest]

Re: Tender - recommendation

Recommend that you also look at www.suzukimarine.co.uk

I bought one of their dinghys and v. happy (although the colour does show the dirt!). Mine's aluminium floored, so v.heavy, but you may prefer one of their inflatable floors...?

 

[Guest]

Re: Tender - recommendation

We have two outboards, a 2.5HP strictly for use as a get us ashore motor and a larger 5 HP Mercury that we use for holidays and when we have children on board. We only carry one at a time

There is no question that the larger outboard is better, it is significantly quieter, smoother running and has proved to be more reliable. Also in any sort of chop the higher speed of the dinghy casts the spray aside so we don't get a wet bum. Against that, as others have pointed out is the weight, with me in the dinghy my wife can pass it down reasonably safely - a strop from the end of the boom or a custom bracket would make life easier.

We have a Zodiac Fastroller 2.5m inflatable wihich has an inflatable floor and keel - when pumped up hard it is rigid and will always plane easily with one, and ususally with two people on board depending on other load.

At places such as Alderney and Dartmouth where signicant distances are travelled in the dinghy the larger motor wins every time, at Yarmouth then its not worth the trouble.

When conditions are suitable, planing in the Zodiac at high speed is great fun and is suprisingly quiet

Martin

 

[rich]

Re:4 stroke not for tenders

4 stroke outboards are not the best for tenders, you can only lay them down one side only, you have to lift it upright, and walk like a pregnant duck.

 

[Guest]

Re:4 stroke not for tenders

Rich

Thanks for the tip - I had intended to go with 4 stroke although given that people are guiding me towards something small the only option would have been the Honda 2HP which I think might prove a little too small.

Can I infer from your comment that a 2 stroke can be layed down on either side and be carried horizontally?

p.s. love the description of what I am likely to look like carrying this thing!!

 

[Guest]

Carrying 2-stroke

Only thing is to make sure that no water drains back into the powerhead - ie keep exhaust lower than head. Shouldn't be difficult with a small, light modern engine.

BTW I think that the Suzuki 2.2 is about the lightest, not sure about the exact weight, followed by Mariner/Tohatsu/Merc 2.5 at about 13kg, with the Mariner/Tohatsu/Merc 3.3 at about 14kg. See websites for more authorative info than my fuddled brain!

Cheers,
Rich.

 

[duncan]

Re:4 stroke not for tenders

I would echo all said on this page.
I bought 4hp / Mercury 4 stroke for a 2.8 inflat. floor/keel etc.
Yes it planes, yes its up to trips and exploring but I would have bought the lightest 2 stroke with hindsight.
Road test them - ie walk arond and handle them - pass one back and forwards between to people etc.
Good luck