Volvo Penta - Low Speed Mode - Throttle Setting

[CURIOUS2]

I have the the above button on my throttle control lever with a single D3. It doesn’t work unless I pay My Volvo dealer to activate it. Effectively it halves the tick over revs and therefore reduces minimum boat speed by 50%. I may find this useful at my home marina which I have to lock into. When the lock is crowded a single click on the throttle tends to give to much power and makes finessing the three foot gap between boats difficult to achieve. Does anyone have experience of the VP Low Speed function and do you find it useful around marinas etc.

 

[Elessar]

I have the the above button on my throttle control lever with a single D3. It doesn’t work unless I pay My Volvo dealer to activate it. Effectively it halves the tick over revs and therefore reduces minimum boat speed by 50%. I may find this useful at my home marina which I have to lock into. When the lock is crowded a single click on the throttle tends to give to much power and makes finessing the three foot gap between boats difficult to achieve. Does anyone have experience of the VP Low Speed function and do you find it useful around marinas etc.

It's cheaper to do a day's own boat tuition. Three feet is easy!

 

[stelican]

Sounds a useful add-on, I will be interested to read from people who have the option.
On some large engine/gearbox set ups you have the option of a trolling valve useful for tight manouvering situations and some angling practices.

 

[Elessar]

Sounds a useful add-on, I will be interested to read from people who have the option.
On some large engine/gearbox set ups you have the option of a trolling valve useful for tight manouvering situations and some angling practices.

Work of the devil that lets the clutch slip. I would disable it if my boat had it.

 

[stelican]

Work of the devil that lets the clutch slip. I would disable it if my boat had it.

Are you absolutely sure? It seems odd that manufacturers should design something to fail.
No problem if used correctly.

 

[Elessar]

Are you absolutely sure? It seems odd that manufacturers should design something to fail.
No problem if used correctly.

The only ones I have known allow the clutch to slip. There may be other ways……..

 

[stelican]

The only ones I have known allow the clutch to slip. There may be other ways……..

Yes but the multi clutch plates are in oil.

 

[jrudge]

Cat have a button that just reduced idle rpm.

to add such a button to an electronic throttle would be easy with about £5 of bits ( switch. /wire / potentiometer ) but it seems a faf on a small boat

 

[Elessar]

Yes but the multi clutch plates are in oil.

I still don’t want it slipping. If you do that’s your shout.

 

[scottie]

Strange though that a method proven in commercial use particularly with trawling applications should be anathema to toy boats

 

[Alicatt]

A nice explanation of how the trolling valve works in Spanish, it can auto translate into English in the closed captions.

Demonstrating the trolling valve on a Cummins engine with ZF gearbox

 

[ss2016]

I have a D6-400 and DPI which has a 'snail'mode. I am not sure if this works the same way as yours does. When engaged the revs don't vary but the prop turns more slowly.
Is it useful in the Marina was your query I think? Well, for me, no. It engages very slowly and I find it easier for manoeuvring to just put it in gear and back out since this is almost instantaneous. It's a big push but can be very brief.
When the boat was demonstrated to me by the dealer I asked which way he manoeuvred. It transpired he also found 'snail' mode too slow to respond.
I do wonder if it might be useful in Inland waterways to avoid exceeding a speeding.

 

[Rangerman]

On the D3 its a trolling valve on the back end of the gear box which reduces the prop speed nothing to do with engine RPM

 

[Andyroonot]

I have a D6-400 and DPI which has a 'snail'mode. I am not sure if this works the same way as yours does. When engaged the revs don't vary but the prop turns more slowly.
Is it useful in the Marina was your query I think? Well, for me, no. It engages very slowly and I find it easier for manoeuvring to just put it in gear and back out since this is almost instantaneous. It's a big push but can be very brief.
When the boat was demonstrated to me by the dealer I asked which way he manoeuvred. It transpired he also found 'snail' mode too slow to respond.
I do wonder if it might be useful in Inland waterways to avoid exceeding a speeding.

When you say it engages very slowly, do you mean there is a delay between you putting it in gear and it going in gear?

 

[Andyroonot]

I have the the above button on my throttle control lever with a single D3. It doesn’t work unless I pay My Volvo dealer to activate it. Effectively it halves the tick over revs and therefore reduces minimum boat speed by 50%. I may find this useful at my home marina which I have to lock into. When the lock is crowded a single click on the throttle tends to give to much power and makes finessing the three foot gap between boats difficult to achieve. Does anyone have experience of the VP Low Speed function and do you find it useful around marinas etc.

It doesn’t actually change the engine RPM, it just reduces the prop shaft RPM, or is that what you meant?
Given your description I would say it would be a useful addition in that situation although I must confess I have only ever installed it and used it briefly & my opinion is not based on long-term use.
Worth mentioning that it’s a software and hardware change unless your gearbox output flange already has the speed pick-up wheel & sensor fitted?

 

[CURIOUS2]

Thank you Andyroonot for your explanation which is most informative and helpful.