Upgrade to a Beta 50 Greenline from canaline 38?

[stevencarr29]

Thanks everyone this has been really helpful

[cuthound]

9 hours ago, Tony Brooks said:

As there is very little chance of you being able to use all the 50HP and probably all of 43HP before you reach the maximum hull speed why not fit a slightly undersized prop. That would give higher engine revs at any given boat speed.

 

When I got my boat (60 foot narrowboat with Beta 43/PRM150),  the previous owner had specified an undersized prop (17"x11").

 

I found the boat took waaay to long to stop, so during last years docking for blacking, had the prop changed for the Beta recoomended size of 18"x12".

 

What a difference, at 3mph the engine speed has dropped from 1500rpm to 1250rpm, the boat stops in less than half the distance, and over the one tankful I have used since, fuel consumption seems to have decreased.

 

The only downside is a slightly increased tickover speed, 2.0mph against the previous 1.8mph according to my gps app.

Edited July 17, 2020 by cuthound
To remove a duplicate post.

[Tony Brooks]

1 hour ago, cuthound said:

 

When I got my boat (60 foot narrowboat with Beta 43/PRM150),  the previous owner had specified an undersized prop (17"x11").

 

I found the boat took waaay to long to stop, so during last years docking for blacking, had the prop changed for the Beta recoomended size of 18"x12".

 

What a difference, at 3mph the engine speed has dropped from 1500rpm to 1250rpm, the boat stops in less than half the distance, and over the one tankful I have used since, fuel consumption seems to have decreased.

 

The only downside is a slightly increased tickover speed, 2.0mph against the previous 1.8mph according to my gps app.

all true but the OP seems to want to fit an oversized engine yet keep the alternator revs up so what I said is one way. Remember the 50hp engine would swing a larger prop than a 38 or 43 so all I am suggesting is he fits a prop closer to the 38 or 43 one so it shoudl still stop as well as if it had one of the smaller engines with the correct prop.

[Tracy D'arth]

15 minutes ago, Tony Brooks said:

all true but the OP seems to want to fit an oversized engine yet keep the alternator revs up so what I said is one way. Remember the 50hp engine would swing a larger prop than a 38 or 43 so all I am suggesting is he fits a prop closer to the 38 or 43 one so it shoudl still stop as well as if it had one of the smaller engines with the correct prop.

Revs on the alternators is not a problem, its only getting pulley sizing correct that matters.

[Tony Brooks]

49 minutes ago, Tracy D'arth said:

Revs on the alternators is not a problem, its only getting pulley sizing correct that matters.

I agree and said as much a fair while ago in this topic but I suppose that if you cruised a modern engine at sat 1000 rpm and pullied it for good cooling at that speed there is a chance (by no means certain because I have not worked it out) a big hand full of emergency reverse might over-speed the alternator. I would want to know what the maximum speed of the particular alternator is so i could check.

[Tracy D'arth]

16 minutes ago, Tony Brooks said:

I agree and said as much a fair while ago in this topic but I suppose that if you cruised a modern engine at sat 1000 rpm and pullied it for good cooling at that speed there is a chance (by no means certain because I have not worked it out) a big hand full of emergency reverse might over-speed the alternator. I would want to know what the maximum speed of the particular alternator is so i could check.

I would be quite happy running an alternator at 18000 revs. With the possible common around 4 to 1 increase of engine speed that is 4500 rpm on the engine, QED you are not going to overspeed an alternator on a boat diesel;

Maximum output is normally over 2500 rpm so 700 RPM on the engine at 4 to 1 is fine for charging, a bit more helps with cooling, the fans are not super efficient on alternators.

Always make sure that you are running it in the right direction so that the fan pulls cooling air in to the rear where the electronics are.

TD'

Edited July 17, 2020 by Tracy D'arth

[Tony Brooks]

I have always taken 18,000 rpm as a typical a maximum alternator speed but the maximum no load speed on a 1.5 is 4400 rpm and at 4:1 its getting a bit close for my liking, not that you should ever rev them that high but people do funny things and/or have accidents..

[Antarcticarian]

On 16/07/2020 at 16:46, stevencarr29 said:

I am specifying my electrical and engine requirements before I get The Fit-Out pontoon to draw everything up for a few boat builders and I have seen that the base spec I am being offered is a 38 canaline unit with an upgrade option to a Beta 43. I am more than prepared to pay for the Beta 43 but for a few £100 more I can get a Beta 50 which comes with the PRM 150 and dual alternators with the ability to upgrade to a 24v domestic alternator which would work well with my proposed 48/3000 Victron Multiplus II inverter charger.

 

Has anyone got any thoughts on whether the Beta 50 is a bit over the top for a 60ft semi-trad josher or am I on a winner?

 

PS I know I probably need dual skin tanks which will be more £ but I like the idea of the better torque.

 

Any help much appreciated

 

Steve

My understanding is that the Beta 43 as standard comes with a 45amp and a 175amp alternators, a PRM150 Hydraulic gearbox and a deluxe control panel.