SternPowr hydraulic steering - internal-external?

Nidza · 02 May 2018, 05:58

Currently I use original SternPowr (model 103) manual steering system (so called internal system in their manual book), which was made by Hynautic. It works, but it always have some leak issues (not constantly, but here and there). I am thinking of changing it to external one, so I hope for a couple of tips from experienced members here.

The main reason I do not like the current one is because the ram with its hoses is under water, so only possible way to service it is by pulling the boat out of water (since the issues are always around the hydraulic ram). The ram is original and I did overhauled it. The ram is made like it was not intended to be overhauled ever and made of aluminum, so "I am never sure" how really good the repair was/can be. By the way, is this the only outdrive with steering ram under water? Beside being unserviceable while in the water, it is also subjected to galvanic corrosion (yes, it is connected with breaded hoses to make electrical contact with the transom housing). The third reason I do not like it is because if the boat is left for longer period in the water without using it, since the ram is in the middle of the shaft and shaft is on both sides, you cannot protect the shafts from "slime" and growth like you can in case of trim/tilt rams by pulling the shafts inside the ram. And the fourth reason would be availability of the ram and its high price. Currently, I am in fresh water, but you can tell me if it is even more PITA in seawater.

So here are a couple of questions:

1. Do you find explained issues as a good reason to take the route of changing to steering ram and its hoses which will be mounted above the water? Or would you keep the original ram and hoses, just maybe buy a new ram (but at extremely high price)?

2. Do you find external ram as a better case if ram and its hoses are above the water, but relatively close to the water, just above the outdrive on the external side of transom? It will be in the mist and sun, but at least serviceable (removable) while in the water, so is this better or worse than being completely under water?

3. Has anyone here done it with SternPowr outdrive? If yes, is there a brand which already has substitute kit for the current outdrive? I am thinking of finding suitable Seastar ram and keeping the Hynautic helm and expansion tank. Of course, I would have to reroute the hoses to ram and plug the current underwater hose adapters. If sterndrive mounting plates are not available from Seastar, I would try to find them from Latham or wherever if possible. But the best option for me is if someone has already done it and can tell me that some brand has ready kit for this outdrive.

Thank you in advance for the tips and answers!
Nidza

boristhebold · 02 May 2018, 06:55

I dont have experience with your set-up, however anything that comes into contact with salt water will be a PITA at some point in life as anyone with a boat in sea water will know, im often amazed by the destructive nature of salt water on electrics and mechanics.

I have a seastar system which sits on the transom probably about inline with the bottom of the large engine cover on a 200hp yam, haven't had any trouble with it as long as I grease the various grease points with marine grease and top up hydralic fluid if needed each year, and of course I wash down the boat with a hose every time I come back from a day out which includes a spray of that area.

I guess if your thinking of more adventures in salt water and you allready think what you have is a PITA then you really have only one choice, if not taken it will bug you I guess and you could get worse issues. Change it is my advice.

beamishken · 02 May 2018, 07:31

Volvo use rams under water and had similar problems mainly with growth on the rams which got dragged into the seals causing damage. Their answer was a pair of rubber bellows to cover the rams which helped keep growth off and alowed for some lubrication/ grease to stay in to help with corrosion
Maybe you could look at something similar

Last Tango · 02 May 2018, 08:57

Can it not be converted to their "External" system ?

Nidza · 03 May 2018, 07:33

Quote:

Originally Posted by boristhebold

I dont have experience with your set-up, however anything that comes into contact with salt water will be a PITA at some point in life as anyone with a boat in sea water will know, im often amazed by the destructive nature of salt water on electrics and mechanics.

I have a seastar system which sits on the transom probably about inline with the bottom of the large engine cover on a 200hp yam, haven't had any trouble with it as long as I grease the various grease points with marine grease and top up hydralic fluid if needed each year, and of course I wash down the boat with a hose every time I come back from a day out which includes a spray of that area.

I guess if your thinking of more adventures in salt water and you allready think what you have is a PITA then you really have only one choice, if not taken it will bug you I guess and you could get worse issues. Change it is my advice.

Thank you for your advice and review of external system.

Quote:

Originally Posted by beamishken

Volvo use rams under water and had similar problems mainly with growth on the rams which got dragged into the seals causing damage. Their answer was a pair of rubber bellows to cover the rams which helped keep growth off and alowed for some lubrication/ grease to stay in to help with corrosion
Maybe you could look at something similar

Good idea, but hardly, if at all, achievable with the current "internal" ram. It could be attached on both sides to the ram cylinder, but on the other sides where the shaft ends are, it is not easily doable due to construction and how they are attached to the outdrive. The hose connections are also at the shaft ends, not on the cylinder body, obstructing possible sealing of rubber bellows. You can see the diagram of that cylinder at page 51 (pdf page) in the manual book on the following link:
http://www.sternpowr.com/pdf/100serieshires.pdf

Quote:

Originally Posted by Last Tango

Can it not be converted to their "External" system ?

Well, good question, I will ask Lancing marine since I have only once, long time ago, got the answer from StwernPowr referring me to Lancing marine. Their external system is shown on page 52 (pdf page) in same link as above, but it seems fairly standard to me and that any available system can be attached for which finding parts would not be a problem in the future. Of course, ready kit for the setup would be an advantage.

Thanks everybody. I still hope that someone with the same setup will also answer (Halmatic Pacific owners maybe).

GuyC · 04 May 2018, 06:17

I've got a Pac 22 with a SternPowr 101 however along with most / all the Pac's it has the internal system.

On the top of the power leg part of the drive there is the hole for putting the hook through for lifting the drive but there is also two threaded holes. You can see these in Figure III-6. Looking at Figure III-9 these holes are to mount the bracket for the external steering.

https://www.asap-supplies.com/steeri...ering-cylinder

ASAP do a hydraulic steering ram which looks similar to the one shown in Figure III-9. I haven't investigated this at all but all the bits look to be readily available and the stern drive should be configured to accept the external steering.

It seems a good idea and I'll certainly consider it when my steering cylinder starts giving problems. Changing the steering ram gets rid of a third of the problem as you will still have the lift trim rams under water. I wonder if these could be attached to the same bracket?

Nidza · 04 May 2018, 08:39

Quote:

Originally Posted by GuyC

I've got a Pac 22 with a SternPowr 101 however along with most / all the Pac's it has the internal system.

On the top of the power leg part of the drive there is the hole for putting the hook through for lifting the drive but there is also two threaded holes. You can see these in Figure III-6. Looking at Figure III-9 these holes are to mount the bracket for the external steering.

https://www.asap-supplies.com/steeri...ering-cylinder

ASAP do a hydraulic steering ram which looks similar to the one shown in Figure III-9. I haven't investigated this at all but all the bits look to be readily available and the stern drive should be configured to accept the external steering.

It seems a good idea and I'll certainly consider it when my steering cylinder starts giving problems. Changing the steering ram gets rid of a third of the problem as you will still have the lift trim rams under water. I wonder if these could be attached to the same bracket?

Thank you for the answer. Yes I am aware of those threaded holes, and I hope that there is ready made bracket, because if I am going to build it myself it is important to calculate the geometry correct. Actually, in the link you have posted, all connecting joints are not shown, but it is really important to have all the joints since it has to follow the drive during trim/lift operation i.e. see the pictures of rams in the following link:
Latham Marine

You are right that it is 1/3 problem less, but I do not find that big of a problem with trim/tilt cylinders (yet). Mostly they are fully retracted and rarely actively used (again fully retracted when unused in water which is good against growth on shafts). In the worst case, you can even fix the leg without trim cylinders (I know some people did that and they are happy with it, like small outboards with adjustable pin, well no more work related to it). The idea you have about connecting trim/tilt cylinders above the water, similar to external steering system, is probably not achievable yet, everybody would use it and the problem probably lies in the forces they have to deal with. They are mostly almost inline with the propeller shaft since when they are not retracted the whole thrust of propeller is pushing the boat through the cylinders (hydraulic system), that is how you can indirectly measure the thrust by measuring pressure inside trim/tilt system, but only when they are not fully retracted (when fully retracted, pressure in hydraulic system is zero). SternPowr had the instrument for that, page 129 in their manual, but it is interesting that its maximum scale was 2000psi which is not enough and even in trim/tilt pump service manual the procedure for test shows that it can go up to 3000psi, now, don't ask me how do I know this, let's just say that I have one dead pressure instrument from SternPowr, although I must say, it is very bright idea. Anyway, the point is that is a lot of pressure or force and one could not trust to brackets for such forces (and there are two cylinders, not one, probably for the same reason).

Pitcrew · 31 October 2019, 20:36

I have a really old Sternpowr 80 series on what I think is a Cheverton built Levi Corsair. The leg has two sets of holes where it locks in, one set behind the other. Which means a slightly different angle when cruising. I have an old Diesel engine which runs about 2000 RPM. I’d like to know what is the best setting for the boat and I’d be grateful for any advice or suggestions.

GuyC · 01 November 2019, 19:53

Pitcrew - welcome to (posting on) the forum.

Whilst I have a SternPowr, it is a 100 series with power trim so there is no locking in. I'm assuming this is what the holes do although it sound a bit odd as being able to adjust the trim is one of the benefits of a stern drive.

I can only suggest you try it in both settings and assess which one gives you the best outcome.

A quick Google of a Levi Corsair produces a nice looking motorboat.

Lancing Marine seem to be the only people in the UK that mention a SternPowr 80 on their website.

Pitcrew · 01 November 2019, 21:02

Thanks I think the forward holes might be best, but I do intend to try both. It is a really old boat and a really old leg, plus a very old Diesel engine.
Can I ask where you get spares?
Regards,
Charlie

GuyC · 03 November 2019, 19:26

Lancing Marine do some SternPowr spares and there is a firm in the midlands Midland Marine Propulsion Systems - mmcltd, Stern Power, Powr, Mercruiser,Yanmar, stern drives, hydraulics, transmissions, boats and jet skis, inboard, outboard, drive systems, engines, wolverhampton that advertise spares for SternPowr 100 drives.

The US still mentions SternPowr on some of their forums but I've never investigated as to whether spares are available.

Due to the lack of spares, should / when my existing drive fails, I'm resigned to either buying another used SternPowr or going for something newer.