Buy a Dinghy Motor or No?

[SomeGuyInaShirt]

I've been out cruising on my tiny little Westerly Centaur a few times now and am preparing for my first multinational cruise which will begin in the spring. I feel like cruising would be more interesting if I had an outboard motor for my inflatable dinghy. Most of the time I just stay on my boat because rowing even a mile takes forever and is nearly impossible in any kind of wind. I'm also on a really low budget so I'm leery of spending. It's probably very useful to be able to travel long distance via dinghy though. Probably a lot of fun and a nice backup should my boat's inboard engine fail at some point. I don't know, what do you think?

[SailingHarmonie]

Rowing almost ANY inflatable dinghy is a miserable task, for sure, and in any kind of wind can be close to an impossible one.

A lot depends on where you are actually going, but in our experience an outboard is a vast improvement to our lifestyle. You have a small dinghy, you can use a small outboard. Modern outboards are very reliable, and don’t take a lot of expensive care.

[MicHughV]

I've just responded to your liferaft thread, and now I see you are here again, wanting to row an inflatable dinghy.
Crazy !
A 2hp outboard will push you right along. If you can't afford such a small motor, stay where you are. Trying to row an inflatable dink in contrary winds, seas and current is going to get you into trouble fast.

[hugosalt]

Although may not be much help if your inboard not operating a short shaft trolling motor will be a big improvement over rowing especially in close in protected waters which your draft (3 ft?) should allow. I chose to use Minn Kota saltwater model with my 9' 6" air floor inflatable, weighing in at 55 lbs. for several reasons, no gas on board, light weight at 18 lbs., compact/easy to store, and I run it off a 35ah AGM battery (actually have 2) which I charge from a solar panel. Solar panel/batteries are separate and independent from house, but do give me an additional 70ah when/if needed and
they power my diesel heater when weather gets cool.
My 30 fter only draws four and a half so I'm anchoring close in,
your not going to be going much faster than rowing,
battery will last a few hours if not run at hi speed,
when sightseeing I put both batteries in dinghy so if one runs low I can always
get back (has never been needed).
If I run down both batteries, solar is slow to charge and I have connected/charged from motor.
Not ideal but my answer to rowing.
If room allows and can carry gas a small 2/3 hp outboard will be
be a big difference in speed/range.

[SV Confianza]

A friend of ours trash picked a 4hp motor and got it running again. Just had to rebuild the carburetor. It’s now his preferred engine because it’s light enough to take on and off the boat himself with one hand.

It will be a pretty big improvement to have a small dinghy motor.

[Drunkonwatch]

Find a hard dink to row

[Adelie]

Originally Posted by SomeGuyInaShirt

I've been out cruising on my tiny little Westerly Centaur a few times now and am preparing for my first multinational cruise which will begin in the spring. I feel like cruising would be more interesting if I had an outboard motor for my inflatable dinghy. Most of the time I just stay on my boat because rowing even a mile takes forever and is nearly impossible in any kind of wind. I'm also on a really low budget so I'm leery of spending. It's probably very useful to be able to travel long distance via dinghy though. Probably a lot of fun and a nice backup should my boat's inboard engine fail at some point. I don't know, what do you think?

So there are a couple things to consider, both have to do with you.

A. What's you budget?

B. How far and fast do you expect to need to go to get to shore?



Let's deal with B. first because it impacts A.



If you are going to be anchoring within 1 or 2 nm of shore and provisions, then you probably don't need to reach planing speeds (9-12kt), plodding (displacement) speeds of 3-3.5kt will probably be adequate. In between is plowing speeds where you use more horsepower and fuel to go only slightly faster. If you think you will need to go 10-15nm to get to town, or to go diving, or to meet another vessel for dinner or picnic then you need to plane or take the mothership and anchor there.



If you can accept plodding speeds (3kt or so) then there are 2 budget options;

1. Electric trolling motor

2. Used 2-3hp motor



1. Riptide 45lb thrust saltwater trolling motor is $370, battery (Trojan 150Ahr deepcycle) is $225; high efficiency replacement Kipawa prop is $37. Somewhere around $650 delivered but excluding tax. This should exceed 3kt light, and just get you to 3kt loaded with provisions. If you want to make this really neat, some aluminum struts and a 75-100W solar panel mounted flat above the motor and you have "unlimited" range and no need to recharge the battery from the mother ship. For $250-300 you can get a much lighter LiFePo 50Ahr battery that will be easier to load and unload, but will provide 1/2-2/3 the range.



I have a 30lb thrust motor on my Cal-20, (3000-3500lb loaded) and can make 2-1/4kt. I would expect you to be able to do similar or somewhat better if you put the 45lb thrust trolling motor on the mothership, waterline length makes tons of difference despite the increased displacement.



Given that you have a Centaur, I assume you are in the UK which means radically different prices for the above items.



2. Used ICE motor. Well under $1,000. These size motors have an integral fuel tank. Dinghy peed fully loaded will be 3-1/2kt or slightly better. If you want to be able to mount on the Centaur you will need to spend more money on an outboard bracket. With a Honda 2.3hp you would be able to get the Centaur to 3.3kt loaded in flat water. A 3hp motor would get the mothership past 4kt, but the dinghy probably won't make 4kt, waterline length would be too short. Honda is very light and easy to move back on forth between dinghy and mothership but loud due to air cooling. For motors in this size the makers are Honda, Yamaha, Suzuki and Tohatsu (Nissan, Mercury et al are rebadged Tohatsus) and various off brand Chinese makes.



https://forums.ybw.com/index.php?thr...-knots.453572/



If you feel you need to plane, you might be able to get just you and the dinghy on a plane with a 6hp outboard. It would help your chances if you had a small tank (3gal) instead of 6gal) with a long hose so the tank could be in the boat, throttle extender so you can sit forward and a flatter larger diameter prop for the hole shot. There are after market fins you can attach to the ventilation plate that will also help get on a plane. The hole shot is when you use lots of thrust to get the boat out of its hole in the water and onto a plane. The flatter prop allows you to use the full power of the motor at a lower boat speed so more thrust and more efficiency. The tradeoff is a lower top speed.

[JPA Cate]

After Adelie's lovely analysis, I have to say, it's valid and it is one way to approach the situation. On the other hand, you can buy plans, fabricate a lightweight [perhaps even a nesting dinghy for the extra waterline length and the ability to split it into two rowable boat for those times when you want two dinghies so each of you can go somewhere different] And, throughout all our years of cruising, we just tried out things. If something was likeable, we kept it and did it that way; if not, we tried out something else.

So as far as dinghies go, having a rowing dinghy is probably the most ecologically sound: can be made from renewable timber, lasts long if well cared for, and is great for exercise.

However, if stability is your main criterion, you either want a catamaran dinghy, or an inflatable RIB.

If speed is your big deal, you want a planing dinghy, with a big unecologically sound engine. We use a 2 cycle Yamaha 15. For us, it has proved itself to be the best compromise for our needs. But, people's needs vary considerably, depending on what you use the dinghy for.

If you want to go miles from where the big boat is anchored safely, for shopping, laundry, or diving (skin or SCUBA), your needs are greater than just ship to shore. We have good friends who always had to anchor closer to shore than we wanted to be, because they rowed ashore in an Avon Redcrest --a hypalon inflatable dinghy, with decent rowlocks-- but a tiny dinghy; and, it served them well.

Dinghy choices are determined, imho by how you expect to use it, but interfered with by the gods of chance who throw alternatives at you that you had not previously considered.

Ann

[Pegu Club]

Get yourself a small displacement outboard, like a Honda 2.3 hp or a Yamaha 4hp, etc, life will get better the very first time you are not required to row,

Fair winds,

[Adelie]

JPA:

I have a personal preference for hard dinghies.

Alas the OP already has an inflatable, they are severely budget limited and they have a very small boat which would be hard to find storage for a hard dinghy, even a nesting dinghy. I'm not saying a hard dinghy couldn't fit, but it would be difficult and it would probably exceed the cost of getting a small motor and using the existing dinghy.


Pegu:

My feeling is that anything over 3hp isn't really going to push a full loaded dinghy significantly faster until you get to 6 or 8hp which might plane the dinghy when lightly loaded.
Looking at engine weights, 2.5 -3.5hp engines weigh about 40lb except the Honda 2.3 which weighs about 30lb.
At 4hp engine weight jumps to about 60lb. This is significantly more to manhandle onto or off of the dinghy when setting up or disassembling for storage.

As a backup for the mothership, larger is better but even the 2.3hp will make 3.3kt in flat water. If there is wind to motor against, put the sails up.

[SomeGuyInaShirt]

FWIW I was looking at a 3.5hp 4 stroke Tohatsu gas outboard or similar. I have West Marine's 2.5m roll up dinghy which is not meant to plane but I will probably buy an inflatable catamaran dinghy from New Zealand next time, not the Takakat but the other kind whose name eludes me. According to their website 3.5khp is enough to get on a plane. The dinghy I have now, we'll I've seen them on YouTube doing 9 "miles" per hour with the same motor. But I'm hearing Tohatsus have reliability issues with their carburetors so now I'm hesitant to shell out the money at all. New equipment really doesn't mean what it used to.

I'd love a hard dinghy, actually I'd really prefer a canoe considering canoeing is how I got into sailing but the crux of that is my boat has an intermediate forestay right in the middle of the foredeck so the only way I could potentially put a dinghy there is if it had a hole through which I could run that stay. Not exactly ideal as I don't like messing with my rig tune. We'll see.

I've bought a lot of expensive stuff for this boat in recent years and I'm kind of regretting it as each item reduces reliability, takes up space and adds complexity so I might just go cruising and see what used options come up.

[Adelie]

Originally Posted by SomeGuyInaShirt

FWIW I was looking at a 3.5hp 4 stroke Tohatsu gas outboard or similar. I have West Marine's 2.5m roll up dinghy which is not meant to plane but I will probably buy an inflatable catamaran dinghy from New Zealand next time, not the Takakat but the other kind whose name eludes me. According to their website 3.5khp is enough to get on a plane. The dinghy I have now, we'll I've seen them on YouTube doing 9 "miles" per hour with the same motor. But I'm hearing Tohatsus have reliability issues with their carburetors so now I'm hesitant to shell out the money at all. New equipment really doesn't mean what it used to.

I'd love a hard dinghy, actually I'd really prefer a canoe considering canoeing is how I got into sailing but the crux of that is my boat has an intermediate forestay right in the middle of the foredeck so the only way I could potentially put a dinghy there is if it had a hole through which I could run that stay. Not exactly ideal as I don't like messing with my rig tune. We'll see.

I've bought a lot of expensive stuff for this boat in recent years and I'm kind of regretting it as each item reduces reliability, takes up space and adds complexity so I might just go cruising and see what used options come up.

All 4-strokes have problems with their carbs, and the smaller the engine the worse the problem because the fuel jets get smaller. The problem is mostly to do with ethanol in the fuel getting old. Ethanol starts getting old at 3mo. Plain gas starts getting old at 12mo.

I don't know if ethanol is an EU problem. In the US if you can't get ethanol free fuel, you can remove it yourself. By adding water, 1/2gsl per 5gal of fuel. Also add some dark food coloring. Shake the container, wait 15min then drain off all the dark colored fluid which will be water mixed with ethanol. There should be about 1gal of mixture leaving you with about 4.5gal of ethanol free gas. Ethanol is an octane booster, so removing it will cause a problem. To deal with this start with a higher octane fuel or use an octane booster. If you use an octane booster, make sure it isn't ethanol, some are. Safer to start with a higher octane fuel I believe.

Ethanol isn't the only thing that can clog jets. I would suggest mounting a Racor glass bowl fuel filter on the inside of the stern and run fuel thru that before it gets to the engine.

I found the video with the 3.5hp planing a 2.5m rollup inflatable. I'm impressed. He used Doel-fins to do it. Apparently he also swapped out the prop.

https://www.youtube.com/watch?v=r1A4HaBY9oM

SGIS are you in the UK or EU?

[SomeGuyInaShirt]

I wish I could post my bug-eyed emoji here because you are obviously a treasure trove of good information. I think you just convinced me to not buy an outboard at all, lol. I take it two stroke is more reliable? I guess I'll have to wait until Mexico to get the 2 stroke as they are not sold new in Canada.

I'm in western Canada right now, I don't expect I'll see Europe again for decades. Hopefully traveling through developing countries means more reliable fuel and engines. We can't get ethanol free fuel in Canada either.

Thanks for your response:-)

[sv_pelagia]

A fellow sailor here in BC.

I have a 4-stroke Yamaha. Has been fantastic for past 3 yrs. You can absolutely get ethanol-free gas here. At all road gas stations (Premium gas) and many marine stations.

Can't imagine depending on ALWAYS/ONLY rowing an inflatable. There are times you will be severely limited. That said, we only use our outboard a couple times/week when cruising full time here in BC.

Doesn't hurt to try without at first, then reconsider.

[SomeGuyInaShirt]

When you use your dinghy do you just leave it ashore and hope for the best? That would give me anxiety. I left my dinghy ashore on Hornby a few summers ago and was half expecting to need to swim back to the boat after my excursion XD.