Twin Engine - Control Question?

[BarryD]

Chap whose boat I'm hoping to buy controls his twin in the marina with one engine only and slight use of the bow thruster. He leaves the starboard in neutral (running and available of course) and just does everything with the port engine.

Now one of the many reasons I'm getting a twin is this illustrious company here have convinced me that a twin is heaps better at going round in circles 'cos you can use the engines to steer the boat.

Naturally I shall give this single engined twin handling a try - but does anyone else have any comments? As I can see the only benefits are it makes the boat move a bit slower - for this alone it makes sense as the lock is pretty unforgiving (twice on Sunday with no mishaps!) and saves a thimble or two of go-juice.

Barry D.

IMHO & FWIW, NWGOI.

 

[cngarrod]

Have no idea.. only got a single.... but how did it go... spill the preverbial then Mr D?????????

Cheers,

CnG

 

[boatone]

Oh Barry..wot a lovely example of how choice can be confusing and create probs you never had before!
As both engines are actually running you can instantly use either or both or even none at all and all at the whim of the master !
As the New York Taxi Driver said when asked how to get to Carnegie Hall......... 'Practice mate, practice..'

TonyR
boatone@boatsontheweb.com
www.boatsonthethames.co.uk

 

[byron]

Well Barry, gawd knows what this guy is doing. He should be gently playing one engine against the other to manouvre his boat. I emphasise gently as too many peeps haul fiercly on their controls and end up with the craft over-reacting. Slowly slowly is the ticket. A bow thruster isn't necessary to a really good boat handler using twin screws its just there as a useful additional facility.

ô¿ô
My wife has not given me permission to express any opinion here

 

[Guest]

He's missed the point Barry. Say if you are coming into a lock to rope up on the port side (or a finger berth)
and you have a strong wind coming from the port side, so the stern is being blown off.

Whilst the thruster may be capable of keeping the bow in, baring in mind only short bursts should be used
with a thruster, the stern will keep coming out unless you use a burst of the stb engine in reverse, to kick
the back in. A burst on the port forward would bring the stern in at the expense of the boat going forward
and you may well be too close to the next boat.

One of the greatest merits of two engines is the control they provide so why not use them. Can't wait
to see the responses from Byron etc. (big anti bow thruster bods.)


cneighbour

 

[BarryD]

MVIII - Sea trial...

Well due to time / tide constraints we didn't get to try her top speed or sea handling but we did bimble around Chichester harbour and down past Itchenor reach.

At a guess she is twice as heavy as MVII so felt really stable, didn't suffer very much tracking - basically went where I pointed her even at low speed. Massive wash though - I will try some trim tab settings to dampen that out but at 4kts she makes twice the wash of MVII at 8kts.

Gotta love that twin turbo whistle though... now if only the board had tol' me about the rumble of a twin six cylinder diesels I'd have skipped MVII totally. And short person loved it both on the water and moored up!

Every thing on board works and everything is so well cared for that it really is like new (only better) 'cos he has fitted some great gizmos and ideas. Only minor fault is that he had a hole cut in the hull for a forward looking depth sounder and then never fitted it. So the hull fitting is in the machinery space with a stern warning don't open as all that seperate you from the wet stuff is the cap.

Barry D.

IMHO & FWIW, NWGOI.

 

[byron]

Aaaargh! I'm not anti-bow thruster I just feel that people rely too much on them to the detriment of pukka boat handling and when the chips are down and they burn out through heavy use are totally incapable of handling their boat. Your point about adjusting the bow to the disadvantage of the stern is well made and I totally endorse it. When I judge boat handling competitions I take careful note of who is forced to use a Thruster because they were not in full control of their vessel using their two engines.

ô¿ô
My wife has not given me permission to express any opinion here

 

[tcm]

Re: yes, and bowthrusters

Bowthrusters are really great...until you need a bowthruster against the wind at which point they are often a bit weedy.

Anyway. When the boat is being driven around, you use both engines. If you use the bowthruster you look like a tit, and I wil laugh and byron will shake his head.

I use the bowthruster for ummm oo yes getting a really tight crossline on the stern and umm praps tiniest bit of lining up the boat to arrive flat on to the quay, but shdn't really need it. Oh, and waking the wife up too!

How to bust the bowthruster: inside the bowthruster are sacrificial "shear pins" like fuses. So if you put a stick in there and then bowthruster it'lll bust the shear pins. Therer are often two shear pins , one of which is a b*stard to replace from inside, and the other which you need a diver or lift the boat out. The inside one can be busted if you really get the nose moving one way and then bosh switch it the other way.

 

[BarryD]

Hey point of order...

Thanks Byron - but I should point out his boat handling on one engine was very good and the hull condition attest to it - and he didn't use the thruster much apart from some station keeping whilst holding outside the lock. He does use the 2nd engine - but seemed to prefer to use just one at slow speeds.

Barry D.

IMHO & FWIW, NWGOI.

 

[Strathglass]

Twin engines

I think your seller is missing the point. The control you have with seperate engines is adequate for virtually all conditions.
I have climbed all the locks at Fort Augustus on the Caledonian canal in a 13 ton twin engined cruiser using only the morse controls in 20 mins. I admit it was between normal lockings and no other boats were coing through. It certainly takes much longer on a single engined craft.

 

[tcm]

Re: one or two engines

I wd always use the both. Both ahead, for example to come clean fwd out of a narrow gap, or perhaps out of a lock. And then both off. Or one , then t'other. Once clear of locks and berths, wdn't use the bowthruster. Buit weird to relipgiously not use one engine - bit like trying to drive to work not using 3rd gear.

 

[tcm]

Re: ah yes

mebbe he was previosuly a single engine user?

 

[hlb]

Barry. Listen carefully.
1. Buy a big round fender.
2. Get SWMBO to hold it between bows and pontoon. ( you can leave it fixed when you've found the right place. but about the place where bows start to curve in at water level.

3. Make sure rudders are straight.
4. Do not touch wheel again till open water.
5 forget the bow thruster you dont need it unless blowing a gale and it will confuss you.
6. Letts say your starboard to the pontoon and theres no wind and you want to go out of a finger and reverse to port.
Put port engine forwards. (No revs on) Starboard in reverese. The boat will start to pivot on the big fender with your back end coming away from the pontoon. The boat drives like a bulldozer or tank.
7. When at the right angle. Move port engine to reverese. The boat will now be going straight back. Maybe need to counter a bit of wind or tide by touching one engine into nuetral or reverse for a second or two. Very easy once you get the hang of it. But remember never to use the wheel. It wont do much and will only confuse you.
Once you get in open water. Still in the marina if you like. Stick a few revs on with one engine forwards and tother in reverse.and spin the boat round in its own space. Then go round the other way.
Mooring. Send SWMBO to the front with big loop of rope. ( Fastened to cleat and through gard rail of course). Drive side of nose up to pontoon cleat so SWMBO can easy lassoo the cleat, leaving a bit of slack. Then tie off. Stick port in reverse. starboard maybe a little in forwards, and your arse end will come back to the pontoon. Mean while SWIMBO has walked to the back, just reaches over or jums off. And fastens stern line. Have you got that!!

Have you sent off Your Stamped. SAE and cheque. Yet.

Haydn

 

[hlb]

Re: Twin Engine - Control Question? *DELETED*

Post deleted by hlb

 

[ari]

Absolutely right for a twin shaft drive boat.

For a twin outdrive boat the effect will be similar but less effective as props too far aft for same sort of leverage, plus steering directs props, thus thrust, which you don't get with shafts.

Basically keeping the helm central will still work, but you'll need loads more reves, better to use helm to direct thrust to help.

So best to use the same principles, but with steering as well for twin outdrive boat.

<P ID="edit"><FONT SIZE=-1>Edited by ari on Mon Mar 25 09:26:13 2002 (server time).</FONT></P>

 

[cngarrod]

Re: MVIII - Sea trial...

Sounds to me like the learnign curve is just beginning.. again!

Holy hulls aside, i guess you will be the owner of Maxum pretty soon then!

All the very best with her mate and have a great time...

Craig.

 

[hlb]

Yes I agree. Must admit I'm talking about shafts. But will as you say also work for outdrives if a little slower. I dont want to confuse Barry with to many instructions. Dont want to see him going baserk turning wheel like hell and switching from one engine tut tother, all in miliseconds. He can do the advanced course latter!! When I had outdrives I didn't turn the wheel very often. You just finnish up leaving it hard over on way and forgetting.

Have you sent off Your Stamped. SAE and cheque. Yet.

Haydn

 

[tcm]

Re: trim, speed

you can't "trim ou"t the wash. It'll make loads of wash cos it's pushing loads of water aside. The wake should seem flat, they say. Can set a throttle setting, and then bog around with trim to get highest speed, but this only works for reliable samey water.

Er, isn't there a 10knot (or 12knot) speed limit in chichester ,and if so, how dya get the diesels whistling?

You should get to see top speed at wide open throttle, wdn't do it all the time but they advertise it so I'd want to see it do (say) 35 with crap underneath, or if crusty or carpety with gunge, 30-something. Praps get the surveyor to do this. The temp guages shd stay 85 F ish.

 

[Deleted User YDKXO]

Barry, I think most people have missed the point that your boat has outdrives rather than shafts, I believe, in which case you can manouevre the stern of the boat using one engine PLUS steering. Unlike a shaft drive boat, you cannot just centre the outdrives and manouevre on throttles alone, you have to steer and throttle at the same time. If you use both engines you can achieve a quicker response and more accurate control but you have to concentrate on 3 separate controls. Actually, just manouevering on one engine/outdrive does simplify things but I think you should learn to use both so that you know what the boat can do
With regard to the bow thruster, its effectiveness depends on its size and power relative to the boat. If you have a 4hp unit, then I think thats plenty big enough in your boat to be very useful. I agree with the assertion that a bowthruster is a bit of a luxury (but v nice to have) on a shaftdrive boat but on a outdrive boat, especially over 30', its almost a necessity because the bow of an outdrive boat gets blown about so easily

 

[KevB]

Totally agree with ari. With outdrives, using the helm can push or pull the stern in any direction with a combination of one engine/both/both reverse/both forward/mix of both. Using throttles alone does have an effect but no where near as much control as using in conjunction with the helm.
A Helm indicator is very useful.