Backing

Sorry Rwidman, that's a*poor excuse for a marina.* The docks aren't even parallel and there is no protection from the current.* Here in central California the typical marina is surrounded by land and breakwater.* So, the major variable is the wind while docking.

Along the Mare Island Strait there are significant currents both up and down stream, typically two knots and sometimes significantly more.* Often approach the marina opening "crabbing" at 30 degrees or so.* A significant issue is silting.**(The high expense and the ponderous permit process greatly impedes dredging.)* Was first assigned to J dock and in a couple of days the four-foot-draft Coot was sitting in three feet of water.* Fortunately, I was "upsized" to K dock.


-- Edited by markpierce on Monday 16th of January 2012 07:39:01 PM

rwidman wrote:KJ wrote:
*

Sidebar:**

If your marina allows transients, does your harbor master/marina jefe

tell them how to pull*in?***** KJ*

Not that I am aware of.* There's a more or less transient boat (supposed to be here for a month but it's been two so far) near mine.* It's stern in.

Here's a photo:

As you can see, the fairway is pretty narrow.* Add to that the tidal current and it's pretty important to have good control as you're leaving the slip.* Most boats can't just pull out of a slip, we have to pull out, back and straighten out, and then leave.* Usually crabbing yo compensate for the current.

Click to expand...

*

*Ron, those boats tied up along side the inside corner must have a hell of a time getting out of there when the tide is pushing them on the dock.

Just wondering, but why are the docks perpendicular to the current? *It seems it would be better if they were parallel with an alongside tie. *Maybe I have understood the whole situation wrong. *If it is like I think getting out of the fariway you would have to crank on some rudder, and pour on the power.


-- Edited by Moonstruck on Monday 16th of January 2012 07:45:28 PM

Moonfish wrote:
In the Pacific NW I think the norm is bow in.

Click to expand...

Squalicum Marina supposedly has something over 2,000 boats in it, power and sail.* Off the top of my head I would say that 99 percent of them are bow-in.* The few I have seen stern-in are that way to provide easier access to the boat because of its configuration.

markpierce wrote:
Sorry Rwidman, that's a*poor excuse for a marina.* The docks aren't even parallel and there is no protection from the current.* Here in central California the typical marina is surrounded by land and breakwater.* So, the major variable is the wind while docking.

Along the Mare Island Strait there are significant currents both up and down stream, typically two knots and sometimes significantly more.* Often approach the marina opening "crabbing" at 30 degrees or so.* A significant issue is silting.**(The high expense and the ponderous permit process greatly impedes dredging.)* Was first assigned to J dock and in a couple of days the four-foot-draft Coot was sitting in three feet of water.* Fortunately, I was "upsized" to K dock.



-- Edited by markpierce on Monday 16th of January 2012 07:39:01 PM

I don't own the marina and I didn't design or build it.* I just lease a slip.* It's close to home, convenient, friendly, and reatively inexpensive for the area.* I could get a slip somewhere else, but my drive from home would increase from 15 - 20 minutes to perhaps 45 minutes to an hour.

I think the two docks were built at different times and the issue was the property line.* That's why they are not parallel to each other.

Click to expand...

*

Moonstruck wrote:rwidman wrote:KJ wrote:
*

Sidebar:**

If your marina allows transients, does your harbor master/marina jefe

tell them how to pull*in?***** KJ*

Not that I am aware of.* There's a more or less transient boat (supposed to be here for a month but it's been two so far) near mine.* It's stern in.

Here's a photo:

As you can see, the fairway is pretty narrow.* Add to that the tidal current and it's pretty important to have good control as you're leaving the slip.* Most boats can't just pull out of a slip, we have to pull out, back and straighten out, and then leave.* Usually crabbing yo compensate for the current.

Click to expand...

*

*Ron, those boats tied up along side the inside corner must have a hell of a time getting out of there when the tide is pushing them on the dock.

Just wondering, but why are the docks perpendicular to the current? *It seems it would be better if they were parallel with an alongside tie. *Maybe I have understood the whole situation wrong. *If it is like I think getting out of the fariway you would have to crank on some rudder, and pour on the power.



-- Edited by Moonstruck on Monday 16th of January 2012 07:45:28 PM

The boats on the inside corner are either dry stack boats waiting for their owners to take them out of the marina or they are fuelling.* Yes, it can be a trick to get out of that area.* It can be a trick to get into it as well if the current is flowing away from the dock.

My slip is about in the middle of the dock on the right side of the photo.* The one away from the dry stack area.* I* try really hard to enter and exit during slack tide.

*

I saw a new Grand Banks 46 or 47 Europa get side ways in one of the fairways of the City Marina. *When the current got the keel, he tried to comme out and was scraping all the bow pulpits and anchors. *A very sad sight.

rwidman wrote:
I don't own the marina and I didn't design or build it.* I just lease a slip.**

Click to expand...

*I'm not blaming you.* Just sorry that's your best choice under the circumstances.

Ron and Mark,

You will definitely learn much about boat handling in a marina like that. *Anyone not familiar with boat handling in a cross current situation should not be allowed. *It seems that Ron deals with it very well.

Many not familiar with areas having an 8' or more tidal range get into big trouble when the current takes hold of their boat.

Here's my GPS track entering and exiting Eau Gallie Yacht basin.* This was the tightest fit we've ever had to try.* Had to back in since the fingers were fixed and about 5 feet long, and we wouldn't have been able to get on or off the boat!

At home I try to back in or at least leave her backed in before I go home since the rude boaters*don't seem to slow down, and I'd rather get waked from the bow.

On a transient dock I do whatever makes it easiest to exit the next day (usually backing in) or if no current or wind I consider where the shore power pylon is located -- I prefer to park so that the pylon is close to the shore power hookup on my starboard bow.*

Egregious wrote:
Here's my GPS track entering and exiting Eau Gallie Yacht basin.* This was the tightest fit we've ever had to try.* Had to back in since the fingers were fixed and about 5 feet long, and we wouldn't have been able to get on or off the boat!

At home I try to back in or at least leave her backed in before I go home since the rude boaters*don't seem to slow down, and I'd rather get waked from the bow.

On a transient dock I do whatever makes it easiest to exit the next day (usually backing in) or if no current or wind I consider where the shore power pylon is located -- I prefer to park so that the pylon is close to the shore power hookup on my starboard bow.*

Click to expand...

*Tight but at least no current and based on the buildings and trees...not near the wind as in many places unless straight down the fairway.

psneeld wrote:Egregious wrote:
Here's my GPS track entering and exiting Eau Gallie Yacht basin.* This was the tightest fit we've ever had to try.* Had to back in since the fingers were fixed and about 5 feet long, and we wouldn't have been able to get on or off the boat!

At home I try to back in or at least leave her backed in before I go home since the rude boaters*don't seem to slow down, and I'd rather get waked from the bow.

On a transient dock I do whatever makes it easiest to exit the next day (usually backing in) or if no current or wind I consider where the shore power pylon is located -- I prefer to park so that the pylon is close to the shore power hookup on my starboard bow.*

Click to expand...

*Tight but at least no current and based on the buildings and trees...not near the wind as in many places unless straight down the fairway.

*You are correct.* No wind, no current.* If there was current then it would be impossible.* I saw a great deal of current in Beaufort (SC) and St. Augustine for instance.* But thier fairways were wider than one boat length.*

On inside of the "T" head in Beaufort*I made every effort to back in since the current would be on my bow when I would be leaving the next morning.* I drove out bow first which was easy against the current.*I watched several near crashes by folks attempting to back out against the current.

To me, it is all about the conditions, and really I like to think more about how I'm getting out then how I'm getting in.* I've done some really rough dockings in my day, *but so far my exits have all been smooth.

We dock bow in.* We have the triangle fillers in the front corners that would prevent backing "all the way" in, we have a sundeck so not really conducive to boarding from the stern, and we prefer the privacy.* Everyone goes to our dock neighbor's boat to socialize so we go there*if we want to join in or*hang out on*our own*boat if we want quiet.*

We have triangle fillers and must bow in. *The real treat is the departure because we are in the number two slip on the inside. *There is not enough room to swing the stern to starboard on departure and we must swing to port, down the way we came. Once out of the slip we are facing the wrong way. *The prior slip occupant, an identical boat, spun 180 and carried on. *I just back the distance. *I feel I have more options if the wind creeps up if I am in the middle of the fairway instead of halfway through a spin. *The neighbors all smile and wave.

cheers

Wow...not sure how wide the slips are at the marinas where a lot of you that bow in...I've been at a marina with triange fillers where almost NOBODY bows in...all back in.* Plus the same at other marinas...wonder if your slips are that narrow or the places I've been at are more tolerant with the bow of boats sticking past the pilings/end of fingers ...I dunno????

Pineapple Girl wrote:
We dock bow in.* We have the triangle fillers in the front corners that would prevent backing "all the way" in...............

Click to expand...

* * * ** Same here.

psneeld wrote:
Wow...not sure how wide the slips are at the marinas where a lot of you that bow in...I've been at a marina with triange fillers where almost NOBODY bows in...all back in.* Plus the same at other marinas...wonder if your slips are that narrow or the places I've been at are more tolerant with the bow of boats sticking past the pilings/end of fingers ...I dunno????

Click to expand...

Our slip is narrow enough that we would be a couple feet off the front of the slip if we backed in.* Certainly wouldn't be conducive to boarding from the swim step, as the sailboat across the dock from*us does.* Their stern is just the right width to fit between the triangles.* The marina allows a 2 foot overhang off the back and technically none at the front, though some anchors hang over a*little.* We fit completely within our slip.*

Pineapple Girl wrote:* We fit completely within our slip.*

Click to expand...

*So your slip isn't showing then.

SD

Egregious wrote:
Here's my GPS track entering and exiting Eau Gallie Yacht basin.* This was the tightest fit we've ever had to try.* Had to back in since the fingers were fixed and about 5 feet long, and we wouldn't have been able to get on or off the boat!

At home I try to back in or at least leave her backed in before I go home since the rude boaters*don't seem to slow down, and I'd rather get waked from the bow.

On a transient dock I do whatever makes it easiest to exit the next day (usually backing in) or if no current or wind I consider where the shore power pylon is located -- I prefer to park so that the pylon is close to the shore power hookup on my starboard bow.*

Click to expand...

*

I was going to humbly admit you are more man than me b/c no way I would want to back my Monk in reverse down that lane, current or not...but then...then I remembered you have twin engines!!! * That's like cheating!

*

single screw= we go bow in.

twin screw= stern first.


-- Edited by Woodsong on Thursday 19th of January 2012 03:25:12 PM

On the rare occasions when someone docks one of the larger boats bow in (usually to be worked on), the anchor ends up hanging over the dock as a hazzard to people on the dock.

Of course, you're supposed to watch where you are walking so nobody says anything.

skipperdude wrote:Pineapple Girl wrote:* We fit completely within our slip.*

Click to expand...

*So your slip isn't showing then.

SD

*Dude, i think that went over their heads.

Woodsong wrote:Egregious wrote:
Here's my GPS track entering and exiting Eau Gallie Yacht basin.* This was the tightest fit we've ever had to try.* Had to back in since the fingers were fixed and about 5 feet long, and we wouldn't have been able to get on or off the boat!

At home I try to back in or at least leave her backed in before I go home since the rude boaters*don't seem to slow down, and I'd rather get waked from the bow.

On a transient dock I do whatever makes it easiest to exit the next day (usually backing in) or if no current or wind I consider where the shore power pylon is located -- I prefer to park so that the pylon is close to the shore power hookup on my starboard bow.*

Click to expand...

*

I was going to humbly admit you are more man than me b/c no way I would want to back my Monk in reverse down that lane, current or not...but then...then I remembered you have twin engines!!! * That's like cheating!

*

single screw= we go bow in.

twin screw= stern first.



-- Edited by Woodsong on Thursday 19th of January 2012 03:25:12 PM

*Woodsong,

After a two month cruise I was totally against twins.* Repairs in Charleston and then again in New Smyrna Beach helped convince me that twice the motors = twice the maintenance.* I hated having two motors!

HOWEVER.** getting into and out of a slip is awesome with twins and is almost worth the extra time and money.** I will consider all of this when I purchase my next boat.

The jury is still out.* At least for me.* I had guys approach me on the dock after I got tied up who told me how good a job I did.* And I just said "I got twins so it was easy."

However, I also saw some sailboats do it better than I did, all relaxed and backing in, and they made me look silly.* I'd say if you can back a sailboat into a slip then you can back anything in.

rwidman wrote:
On the rare occasions when someone docks one of the larger boats bow in (usually to be worked on), the anchor ends up hanging over the dock as a hazzard to people on the dock.

Of course, you're supposed to watch where you are walking so nobody says anything.

Click to expand...

*Ron, we had one on our dock sometime back that so many people had banged their heads on the anchor that someone taped foam rubber over it.

Egregious wrote:
*Woodsong,

After a two month cruise I was totally against twins.* Repairs in Charleston and then again in New Smyrna Beach helped convince me that twice the motors = twice the maintenance.* I hated having two motors!

HOWEVER.** getting into and out of a slip is awesome with twins and is almost worth the extra time and money.** I will consider all of this when I purchase my next boat.

The jury is still out.* At least for me.* I had guys approach me on the dock after I got tied up who told me how good a job I did.* And I just said "I got twins so it was easy."

However, I also saw some sailboats do it better than I did, all relaxed and backing in, and they made me look silly.* I'd say if you can back a sailboat into a slip then you can back anything in.

Click to expand...

*

I hear you on the cost of twins! *All my previous boats to our Monk were twins and the pilothouse we just bought happens to have twins. *I am having the marina the boat is at right now do full service on both engines and generator right now due to distance from me and lack of time to do it myself before we leave on our 275 mile delivery home trip next week. *I am going to have to tell the service yard that their bill is "TWICE what I pay for my trawler and clearly you have overbilled me!" *haha.

The handling of twins is great, the cost, not as so great. *It is a give and take but seriously- I personally would not want to try and back my Monk into the fairway you posted with just a single. *Someone else could do it perhaps but I am not so sure I could. *I guess if I had to perhaps but I've never tried backing down my Monk that far of a distance before so it would certainly be an unknown! *But ah...with twins....not a problem!


-- Edited by Woodsong on Thursday 19th of January 2012 09:30:48 PM

Hey Woodsong,I hope you have faith in the mechanics and the marina to embark on a journey in a new boat.Well,something tells me that you are right on top of the situation.have a safe trip,and also have a fun trip.GOOD LUCK!

Moonstruck wrote:skipperdude wrote:Pineapple Girl wrote:* We fit completely within our slip.*

Click to expand...

*So your slip isn't showing then.

SD

*Dude, i think that went over their heads.

*I just saw it!* Silly Dude.*

1976 Grand Banks twin props

I'm a sailor going from an auxiliary sailboat with a single prop to a trawler, either single prop or twin prop.

I'm looking at a 1976 Grand Banks 36' with twin John Deere's, 107 HP each. The port propeller is 24" x 21" and the starboard propeller is 24" x 18.5".

First, which is the correct pitch: 21" or 18.5" ?

Second, is there something rational to this difference in propeller pitch -- such as correcting steering torque?

Or is it something as simple as the owner having to replace a prop, and he installed the only one he had, which was a different pitch from the other one?

Thx!

JC

Are both gearbox ratios the same?

jwchessell said:

Second, is there something rational to this difference in propeller pitch...


JC

Click to expand...

Yes. We have a twin engine GB36, one of the first fiberglass GBs made. It has a pair of FL120s and BW Velvet Drive transmissions.

Twin engine boats usually have counter-rotating propellers. In some instances, the engines actually rotate opposite directions. But in most cases, the engines both rotate the same way and one of the props is rotated the opposite direction by its transmission.

Most twins have the starboard prop rotating clockwise (as seen from the rear of the boat) and the port prop rotating counterclockwise. The engines, at least the FL120 and probably most engines, rotate counterclockwise.

So our starboard transmission has an extra gear in it to make the startboard prop turn clockwise.

BUT.... fitting an extra gear into the transmission changes the final drive ratio a little bit because of the sizing limitations imposed by the transmission's case.

So even though both engines are going the same rpm at cruise (1650 in our case) the props are not going the same rpm. So to get the same thrust from both props, the slower turning prop is given more pitch.

On our boat as delivered in 1973, one prop had a pitch of 18" and the other one had a pitch of 17." The prop with the 18" pitch had the slower rpm when the engines were going the same rpm.

The original three-bladed props on our boat were changed to four-bladed props by a previous owner. They were supposed to have the same 18" and 17" pitches of the original props, but they didn't. Long story short, when we had the props totally reworked a number of years ago, the prop shop said that they had found having the pitches different between port and starboard really didn't make any difference with a GB36 like ours, and they recommended pitching both sides the same.

Which is what we had them do. They are now both 16" pitch because they're four-bladed instead of three-bladed. One blade still goes slower than the other one at the same engine rpm, but the shop is right--- we don't notice a lick of difference in steering or the directional characteristics of our boat with the slightly different thrust between port and starboard.

But if you have questionss about the props on the boat your interested in, I would strongly suggest you talk to an experienced and reputable prop shop. Information they asked us to provide when we decided to have our props worked over were:

What is the make and model of our boat?
What is the wide-open-throttle rpm (in gear with the boat moving) of each engine?
What kind of engines and transmissions are in our boat?
What is the horsepower rating of our engines?
And finally, they wanted to see the props currently on the boat.

This last obviously had to be complied with by having the boat hauled, but we had it out of the water for other things plus a bottom job so we simply had the props pulled and took them to the shop.

Bottom line--- there may be good reason why the props on the GB you're interested in have the prop diameters and pitches that they have. Don't automatically assume that because the pitches are different, this indicates a problem.