It is all fun until you are feeding fuel to two of these...
It did however get to dive sites rather expediently.....
It did however get to dive sites rather expediently.....
One or two motors (split from 'Is there a valid reason for a pony bottle')
- Thread starter MichaelMc
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
Definition of redundancy pertaining to engineering:
the inclusion of extra components that are not strictly necessary to functioning, in case of failure in other components.
johndiver999
Contributor
It would be smarter to rig each engine with its own control system, fuel storage, filtration and delivery system as well as an independent battery. It would also be unwise not to be able to switch fuel, battery etc, from one engine to another. Twin engines can deliver a certain degree of redundancy and it can be enhanced or ompromised depending on how the boat is rigged
broncobowsher
Contributor
Twin screws come into play when docking. You can just about dock a twin screw boat without steering. One forward, one reverse. Nearly a bow thruster. To a skilled caption.
To an unskilled weekend skipper, it's just 2 levers to push in the same direction instead of 1.
If you know what you are doing twin screws are functional. If you don't, they are redundant.
My weekend skipper duties, single. I know what twin screws can do, doesn't mean I can do it. But I am impressed when I am on a boat with a caption who can.
It can also be pretty funny to watch a weekend skipper trying to move his twin engine boat after one engine stalls and they don't realize it
Also twin engine will typically have redundant electrical system. If the charging system on one engine dies, there is another charging system. May not be enough to keep all the toys powered up, but enough to keep 2 engines powered up. There can be more failures besides just if the engine runs or not.
While at it, how many outboard engine options are there in the 150HP class? And the 300HP class?
A hull designed for one engine or two?
Cost of the engines is generally negliable, they will add up to about the same. But what about mainteneance? Twice the number of seal, twice the props, twice the water pumps. So the twin will cost more to keep running.
Not nearly as cut and dry as some of you are trying to make it out to be. Redundant to make it back on only 1 engine, that is one of the least of the reasons.
To an unskilled weekend skipper, it's just 2 levers to push in the same direction instead of 1.
If you know what you are doing twin screws are functional. If you don't, they are redundant.
My weekend skipper duties, single. I know what twin screws can do, doesn't mean I can do it. But I am impressed when I am on a boat with a caption who can.
It can also be pretty funny to watch a weekend skipper trying to move his twin engine boat after one engine stalls and they don't realize it
Also twin engine will typically have redundant electrical system. If the charging system on one engine dies, there is another charging system. May not be enough to keep all the toys powered up, but enough to keep 2 engines powered up. There can be more failures besides just if the engine runs or not.
While at it, how many outboard engine options are there in the 150HP class? And the 300HP class?
A hull designed for one engine or two?
Cost of the engines is generally negliable, they will add up to about the same. But what about mainteneance? Twice the number of seal, twice the props, twice the water pumps. So the twin will cost more to keep running.
Not nearly as cut and dry as some of you are trying to make it out to be. Redundant to make it back on only 1 engine, that is one of the least of the reasons.
Mine have separate batteries, although they can be combined if needed. Each motor has its own 75 gallon tank, but the term redundancy should not be used for anything that is not extra or unnecessary to propel the boat at planing speed. I have twin Honda 150 outboards, but my only redundancy is my Vessel Assist card.
I have one engine! A 340hp Vortec...if I lose the engine, I’m dead in the water....if I had two, I could do extremely fast circles....I don’t allow Ponies on my boat either...it’s a competition wakeboarding Boat and besides, ponies chit too much!
Shinny! I like shinny!
Unless you have a catamaran as I do. One engine would be pretty squirrely with two pontoons.
I also drive the boat, including pulling out of and into my slip using just the throttles once or twice per year. It's great practice if the steering pump or cables go out.
Except that fuel contamination typically happens at the source tank on the fuel dock moreso than in or on the water. When it does happen on the water its often a fuel separation issue due to age which also hits both tanks anyway. Or #1 cause? Just plain out of gas. None of which redundant engines solve.
Top 10 Reasons Boats Break Down
There are plenty of people (myself included) who have used one engine for long voyages. Two engines gives a false sense of security in many cases because (like with Max here) you can't actually limp home on one engine without burning through all your fuel, or burning up the remaining engine, or being unable to fight the wind/current adequately on one engine anyway. And with two engines you actually have twice as much to maintain - and break down.
So in the end this is not unlike beginners throwing pony bottles at their gas management issues rather than developing the awareness and soft skills to safely use one cylinder or one engine.
lowlysubaruguy
Contributor
Twin 150s will get you on plane and in motion when loaded faster than one 300 and by a fair margin. It will perform better at lower speeds and handle rough water better.
One single 300 will be sluggish in comparison in all the above ranges but wiill produce a higer top speed and reduced fuel consumption.
Todays outboards have proven to be pretty reliable and the redundancy factor on non emergency vessels is reallly not the kind of factor it used to be. Fact is you can have two engines and suffer some electrical issue with two engines and have two dead engines which is more likely to happen then a failure on a late model engine. But having twins still offers some mental satisfaction of more reliable.
As far as a cat goes id like to know how a single engine performs on one my personal belief is that cats over say 22 feet in length need twins to handle well with the amount of side motion they have in certain waves I suspect that a center mounted single outboard might cavitate and loose thrust in a lot of waves where twins one would always be in clean water. Im also talking about ocean sized cats ive been on a couple of lake boat cats in the 21 foot range that are small lightweight boats and are a whole different animal all under 8 feet of beam . Most ocean going cats 22 feet or longer start at 9’6” or more But thats just my ramblings on a friday night.
I also think twin 150s would outlive a single 300 thats ran loaded heavy and at lower speeds say under 35 MPH which is probably what a cat would see but a boat ran at say 45 MPH or more a lot might see a longer life with a single. Just a guess here.
I also have a biased opinion and here is why
One single 300 will be sluggish in comparison in all the above ranges but wiill produce a higer top speed and reduced fuel consumption.
Todays outboards have proven to be pretty reliable and the redundancy factor on non emergency vessels is reallly not the kind of factor it used to be. Fact is you can have two engines and suffer some electrical issue with two engines and have two dead engines which is more likely to happen then a failure on a late model engine. But having twins still offers some mental satisfaction of more reliable.
As far as a cat goes id like to know how a single engine performs on one my personal belief is that cats over say 22 feet in length need twins to handle well with the amount of side motion they have in certain waves I suspect that a center mounted single outboard might cavitate and loose thrust in a lot of waves where twins one would always be in clean water. Im also talking about ocean sized cats ive been on a couple of lake boat cats in the 21 foot range that are small lightweight boats and are a whole different animal all under 8 feet of beam . Most ocean going cats 22 feet or longer start at 9’6” or more But thats just my ramblings on a friday night.
I also think twin 150s would outlive a single 300 thats ran loaded heavy and at lower speeds say under 35 MPH which is probably what a cat would see but a boat ran at say 45 MPH or more a lot might see a longer life with a single. Just a guess here.
I also have a biased opinion and here is why
Attachments
Similar threads
