Monk 36 Rudder

[RickB]

nomadwilly wrote:And the single engined boat has a noticeably higher CG.

How do you do that?

I have crawled all over lots of boats looking for a CG but haven't ever been able to see one.


-- Edited by RickB on Thursday 23rd of December 2010 05:53:07 AM

 

[Nomad Willy]

CG's have red stripes on their boats and give free inspections. The red stripes are so you can see them easily** ...opposite of navy grey.
Actually I'm assuming the engines are lower than boat CG and any weight added to, around, on or in the engine/s would lower the CG. On an OB boat this would not be the case.

 

[markpierce]

How many 200-pound people on the flying bridge*are needed to offset the presumed lower CofG of a two-engined boat over a single?

 

[sunchaser]

The 200 lbers*won't be on the FB very long when big waves come along.

 

[Marin]

nomadwilly wrote:

When GB made twins they used the same engine as the single so they made two boats, both w the same hull but one w twice as much power and one w half as much power as the other. I hope Monk wasn't that stupid.

If you were talking about a displacement boat you'd be right.* But GBs (and other similar boats) are semi-planing boats and so can put the extra power to good use if the owner wants to go faster and is willing to cough up the*money for*the extra fuel.* So "overpowering" a semi-planing boat makes sense if buyers want to go faster, which in the case of GBs, particularly starting in the late '80s, early 90s, was the case.* The typical buyer of a GB42 in the late 1990s, for example, wanted to be able to get to his destination at 15 knots, then cruise the area leisurely at 8 knots, and then make the long run home at 15 knots.* By putting what you would consider way-overpowered engines in the GB42--- a pair of 450 hp Cats (IIRC) in the case of later GB42s--- the owner was able to do this.

So it wasn't stupid design, it was smart marketing.

*

 

[RickB]

nomadwilly wrote:Actually I'm assuming the engines are lower than boat CG

They might be smaller engines mounted higher in the hull than a centerline single. Maybe the VCG is higher than the single.

*

 

[markpierce]

RickB wrote:


nomadwilly wrote:Actually I'm assuming the engines are lower than boat CG

They might be smaller engines mounted higher in the hull than a centerline single. Maybe the VCG is higher than the single.


But then probably not.

*

 

[RickB]

markpierce wrote:But then probably not.

In any event, it's impossible to determine the VCG by looking at a picture of a boat.

 

[Egregious]

nomadwilly wrote:

Woody,
Since you have twins I hope you have two 70hp engines instead of two 140hp engines.
When GB made twins they used the same engine as the single so they made two boats, both w the same hull but one w twice as much power and one w half as much power as the other. I hope Monk wasn't that stupid. But I'm afraid you're going to tell me it is so.
I compared you're stern pics and see that your about 1.5" lower in the water. One could assume it is from the weight of the extra engine but that weight would be far enough fwd so it should'nt show to that degree at the stern. Do you suppose it could be that your'e keel is full of water? Do you know if it is or isn't?
About the rudders. I suspect Monk probably decided you had so much extra power that a tiny loss in efficiency was worth loosing for the somewhat large increase in maneuverability and control. Also It's obvious they probably made the twin w the same engines as the single to minimize inventory complications and expense so they would do likewise w the rudders. Just because a boat was designed and built by "professionals" dosn't mean it was done correctly. If Edwin Monk designed the boat for 150hp no builder has any business putting 300 in it and the reverse is also true. Also in this Monk example the single engine boat has a certain weight capacity and the twin engine has a weight capacity that is a full ton less. And the single engined boat has a noticeably higher CG. I'm not saying they did or didn't know what they were doing or that I know what I'm talking about but they probably did it because GB was doing it and GB was selling more boats. I do take back most of the above if Woody's boat has two 75hp engines.

I see your point.* Maybe* I made a mistake.* But the trips I've taken so far and the knowledge I've gained about boats cannot be taken back.

To be clear, yes they just doubled the 135 Perkins.* Yes the outboard side of the Port side engine is a Bitch to get at.*

My next boat will be a single, perhaps with a bow thruster, but I may not need it.