Lost steerage way, puzzled

[rsn48]

I have an older Catalina 27 that doesn't go astern worth beans, but I've sort of figure out the puzzle on the reversing stuff. Yesterday I had a weird experience that left me baffled and embarrassed. First the history.

Since my hip operation of May 18 2006, I haven't been on the boat much. I experienced a great deal of pain and walking problems initially. In fact it is only recently that my leg has felt any where near normal. This means not only wasn't I using the boat a lot, I didn't haul it out. I left this summer for two months and on my return, I took two friends out boating from the high north, close to the artic circle in Nunavut.

Everything went smoothly backing out, the stern was pointed where I wanted it and the bow swung in the direction I wanted. BUT, when I put in the Mercury into forward I had no steerage way - none. In fact, I did a 360 in front of the world as my two friends were rapidly re-assessing how experienced I was in boating.

I successfully backed the boat into a double empty slip and life seemed to be good until again I put the engine into "forward" and again no steerage, no matter how far over the tiller was; the boat would just go forward, the wind would catch it and again I did another 360 with an every increasing doubtful friends.

This repeated itself one more time before I got the boat to face the correct direction and hit the forward hard for a moment. The only thing I can think of was some how the collection of crud on the bottom significantly altered my forward steerage way. Amazingly my friends didn't chicken out and we had a good time.

We did get out for a couple of hours and on my return, the old sensitive forward steerage I was used to had returned. In all my years of boating, I've never encountered this loss of steerage; it was so pronounced that at one point I wondered if the rudder had some how come off; which of course it didn't.

Any theories?

[Alan Wheeler]

My two cents is that I think you answered it yourself. Too uch growth somewhere important and the run for a couple of hrs has cleaned it up enough to return some stearing. I bet more improvement could be had after a haul out and clean though.

[cooper]

I agree with Wheels. Because the majority of the growth will be forward of the prop, when you go forwards you go all over the place. In astern you are in effect being "pulled" along.

[Fishspearit]

I have a much different answer. I think the issue is because you are using an outboard rather than the traditional inboard. For steerage way you need water flowing across the rudder, which happens immediatly when you go into forward with an inboard engine and prop in front of the rudder. Sailboats traditionally don't back well because in reverse there is no propwash across the rudder. In your case with the outboard prop behind the rudder, you get water immediatly flowing across the rudder in reverse, but you must get speed going on the boat before you have any water flowing across the rudder in forward. End result, with the outboard you will always have better control in reverse until you get moving forward at about 2 knots.

[rsn48]

Fishspearit, although I have the original crappy rudder on the Catalina, in forward it has always been very sensitive, even at half a knot, which is about what I do when my motor is in neutral and I turn into my slip upon returning. The outboard theory does work in reverse, however.

I think the large growth forward towards the bow makes sense. I don't know if what I say next is true or not, it could be. Where I dock my boat is right next to the BC Ferries leaving from Horseshoe Bay in West Vancouver. Some feel that growth is even worse on the bottom of boats because the props from the ferries turning aerates the water more than normal, thus creating a rich environment for growth.

Here is a link to where my boat is docked, on the home page you'll see a Ferry either leaving or coming into port. This port services three ferry routes, all active during the day with many sailings. Vancouver Marina and Moorage - Horseshoe Bay Boat Rental - British Columbia, Canada

[44'cruisingcat]

Originally Posted by Fishspearit

I have a much different answer. I think the issue is because you are using an outboard rather than the traditional inboard. For steerage way you need water flowing across the rudder, which happens immediatly when you go into forward with an inboard engine and prop in front of the rudder. Sailboats traditionally don't back well because in reverse there is no propwash across the rudder. In your case with the outboard prop behind the rudder, you get water immediatly flowing across the rudder in reverse, but you must get speed going on the boat before you have any water flowing across the rudder in forward. End result, with the outboard you will always have better control in reverse until you get moving forward at about 2 knots.

That doesn't answer why the same boat with the same motor would change from being responsive to being uncontrollable. I'd bet, as has been said before, marine growth is the reason.