Sabre 28 - Cruiser - Project

[JawsOrca]

Thanks again.

 

We had problems with Jessicas prop when she went in.. So I suspect we will have problems again.. We have no idea what prop this should have although we have one with the leg.  I guess it will be off to T Norris or Lancing at some point for details on the prop as so we do hit hull speed!

 

Unfortunately we also have no idea what engine she had before.  The sterndrive was fitted we believe but arent too sure for certain (theres evidence that the old transom was cut down a couple of times so thinking is that it had a smaller leg and the old owner put this in because he wanted a v6 petrol!). The BMC was purchased by the previous owner at some point in their unstarted project and never made it in the boat

 

Daves did spot (strangely by looking at the head off picture) it wasn;t a ford engine.. he said the down pipes look the same.  Is certainly a very pretty engine though!

 

That is really interesting what you had to do with the throttle there! I have always wondered lol! Good job though!

 

Thanks again and we hope to see you up there sometime soon!

 

Kind regards, Alan and Dave

[diesel falcon]

Hi,

enjoying this thread, following on from what,s been said about planning hulls, my boat has 2 ,150hp diesels and to get her on the plane you really have to give it some stick!!

 

 

One of the problems with the additional weight of diesel over petrols.These are in a 27ft boat http://www.csgnetwork.com/marinepropcalc.html

 

For your prop, get an idea from this??   

[JawsOrca]

Thanks for this link Diesel Falcon.. I'll take a look through this

 

What boat have you got with these?

 

Our little vetus really looks lost in the vast engine bay.. It's amazing though to see how they manage to squeeze chunky engines in though!

[MBA Marine]

Are you sure thats a 30hp vetus? it looks smaller, but if it is then its almost like for like in HP as that 1.5 BMC you have just gotten shot of. Also you say the mount are very flexible, vetus use those soft mounts on their small engines especially when they have less than four cylinders to reduce noise/vibration.  

Like Strowager has pointed out you may have a problem with engine movement on that very short shaft length, can you not ad a CV joint to remove this risk?, or fit harder mounts but then this will transmit more vibration.

[JawsOrca]

Hi MBA. 

 

Yes its a M4.14 (32hp) (And it has 4 injectors! (i did have to count them to make sure!)) up close it is just a tad smaller than the BMC (I think it looks smaller because theres no gearbox on it too). It also does look tiny in that engine bay but considering you can almost stand up within it though and just be at chest level with the floor. (Our pictures aren't coming out too well). 

 

The rubber dome cv thing on the shaft should (we hope!) allow for some of this movement but we will run it up in the next couple of weeks and see what its like.. We do have some harder mounts if thats needed too, but I really don't want any vibration (we we used to hire Alphas widefire which had a little 3 cyclinder and the vibration on that was terrible, so I really don't want that) but certainly we need to make sure we aren't damaging anything, or we still have some rubber r&d's about so I'm sure we can make other bits up to add more flex on the shaft etc

 

Thanks again

[Guest]

...... you may have a problem with engine movement on that very short shaft length, can you not ad a CV joint to remove this risk?, or fit harder mounts but then this will transmit more vibration.

 

Yes, the more I think about it, the more worrying it is, Mark is quite right to highlight the very potential problem.

 

The top input shaft of the Volvo 280 outdrive has it's universal joints on the outside of the transom, to enable leg tilt and swivel. It picks up the rotary motion of the shaft from the engine via a female spline that engages with the male splne on the end of the shaft that passes through the bearing held absolutely rigidly in the transom shield, (the large alluminium casting that is bolted through the transom.)

 

That bearing was never designed for anything other than axial loading, since the trasom shield is normally bolted directly to the engine bell housing, and becomes one single unit, held rigidly in the centre.

 

Now that yours is modified with that short intermediate shaft, it is still rigidly held at the transom shield end, so you need to give that shaft some flexibility at both ends.

 

The deluxe way to do it is with an Aquadrive coupling, which has UJ's at both ends, and was specifically designed to isolate engine movement from propshaft through hull connections, and take away the need for accurate alignment.

 

Unfortunately, they're very expensive though !

 

A possible alternative would be to use a Vetus Bullflex coupling, which gives a lot more movement than the thinner R&D types.

 

The worry with your proposed more rigid shaft setup is that even if it appears to work ok when initially coupled, it could suddenly fail after months or years of use, which could be awkward in a seaway.

[JawsOrca]

OK thanks, I do understand what you are saying and it does make sense but I'm getting a bit lost as I'm not mechanical minded (and I'm probably going to dig myself a hole!). I'll show this to Dave tonight though how will probably understand more (I'll get him to add a further reply).

 

I certainly appreciate all this input though and please keep it coming! I suspect this set up is a bit abnormal and needs this input!  

[diesel falcon]

Thanks for this link Diesel Falcon.. I'll take a look through this

 

What boat have you got with these?

 

Our little vetus really looks lost in the vast engine bay.. It's amazing though to see how they manage to squeeze chunky engines in though!

Falcon 27 mate ,the reason your engine looks tiny is because your boat can have two v8,s,v6 .s(can,t remember which) fitted fitted as an option!!

[Guest]

Falcon 27 mate ,the reason your engine looks tiny is because your boat can have two v8,s,v6 .s(can,t remember which) fitted fitted as an option!!

 

It'll be less of a concern then, worrying about possible excess weight at the stern Alan !

 

That would indeed mean that the hull form will have a lot of buoyancy  aft, to support that original heavy configuration of twins.

 

In fact, you'll need to be careful to not end up with the bows dipping down when you first put her back in the water.  You mentioned having placed some big tanks further forward.

 

I friend of mine once removed a big sterndrive from a 25ft cruiser and replaced it with a 10hp 4 stroke outboard (just for inland use).  He had to put quite a bit of ballast where the old inboard engine had been, to get her to sit level again, fore and aft.

[MBA Marine]

Aquadives, not fitted one since leaving employment with builders of stooopidly expensive yachts but they are the dogs dooda's!

 

The point about things might look fine at first is also very relevant, did I read that Dave had welded the coupling? if so without wishing to cause offence to his welding skills, A touch of miss alignment and the constant flexing of this this weld could cause it to fracture, also what was welded? was it mild steel to mild steel or was it mild steel to stainless steel? Stainless heat distorts 3x greater than mild, any face attached to a shaft should be faced off in a lathe to ensure the two are at 100% 90 degrees.

[JawsOrca]

Falcon.. I really wished it still had twin v6's

 

Strowager, thats a very good point so maybe we do want bigger tanks back to balance.. we probably will want to test float at some point I guess to look! (we have made the mistake of miss balancing on the sailing boat though) but I didn't think about the lighter engine causing the bows to drop down.. (another thing on the list .

 

Mark, If you look on day 19 (top of this page) you will see a picture of one split coupling. The spline is the same spline that fits the Outdrive bellhousing, so he centered it on a shaft which was a tight fix and clamped the shaft onto the split coupling and the welded that disc onto the split coupling (Both are mild steel) (then removed the shaft), I understand that that was a tight fit so there wasn't movement (although I guess there is a possibility for this to be out I guess thats he's expecting the flexi coupling would take this up).. (maybe I should get him on here to comment!)

[Guest]

I've been thinking about this again Alan, and I'm worried that you adaptation via the intermediate shaft may prove disastrous.

 

I have to admit straight away that all of my practical experience on this is with the Volvo Penta 290 DPA drive, which is a slightly newer model than your Volvo Penta 280.

 

I've been studying the drawings and photos carefully though, and the parts that have me worried appear to be the same in both models.

 

I've tried to explain my thoughts with two images, made from partly my images and partly from a 280 leg on the Internet.

 

The problem is that the VP outdrives rely upon the splined output shaft being rigidly bolted to the centre of the engine flywheel, so it is very strongly restrained from sideways movement by the crankshaft rear bearing.

 

That splined engine output shaft is connected to the splined input shaft at the top of the outdrive by a "gymbal bearing", which is two UJ joints connected by a common middle spider. It's therefore imperative that both of the splined ends are supported firmly against sideways movement.  The outdrive end spline is held firmly in the input bearing housing in the outdrive casting.

 

In your new arrangement, you have cut the engine output splined shaft from the flywheel, so it's only sideways support is the soft rubber seal in the transom shield. This was only ever designed to be a secondary waterproof seal if the outer bellows should ever fail, and stop the boat from sinking, (unlike Mercruiser outdrives !).

 

 It gives no mechanical support to the inner splined end of the Gymbal bearing, so that will slew outwards under centrifugal force and drive load, rapidly wearing the rubber seal and creating more movement and imbalance.

 

I may be quite wrong with this, if your outdrive does not have a Gymbal bearing, but I think it does.

[JawsOrca]

Ok I see what you mean and again makes sense to me. I'll get dave to look through tonight and will come back to you.. this is all part of the fun though! Obviously once again thanks for the input and it shows how valuable it is to be talking about this

[JawsOrca]

Just a quick update. Daves had a good read through this and obviously as I said, he is very grateful for everyones input and time spent on this for us (We certainly owe pints for people who helped

 

He said he's was aware of this (thankfully!) but was going to run with this setup ashore and see what it looked like.. However he is now considering putting a bearing block somewhere so the shaft in the bellhousing can't move and or putting an aquadrive in but will spend a bit of time thinking.   Thanks again

[MBA Marine]

As you did not want to invest £300-£400 in getting the correct adapter to hard couple engine to leg as was intended then I do not see you buying aquadrive units!

 

For the most part you will see that most are happy to read about your progress and we might not agree with some methods, it should be ringing bells that enough people have voiced there concerns about this. 

 

Good luck and please dont go coastal until this has proved us all wrong with a lot of inland testing behind it.

[JawsOrca]

Thanks again Mark. Don't worry we are taking this all constructively and its really good that you are voicing concerns and thats want I wanted when I compiled this blog and we are certainly listening. We aren't bigheaded and use these projects as means to do something we enjoy and learn different skills. I also know that we are way out of our depth with this outdrive, its one reason that made me sleep on the idea of taken the project over before agreeing. I would prefer to have an shaft driven boat for many reasons! But now we do have to live with it!

 

This boat is our boat though and therefore we will spend whatever it takes on whatever it needs  (even if that does mean a change of leg and engine etc).. Although the boat is really only going on the broads so as strowager said the vetus should be ok HP wise/economy wise for day to day use etc.. and as its new (albeit old stock) I'd prefer to use it... I know ideally this leg should have a V6/v8 and as much as I would love that (I really would!) thats not really helpful on the broads (in my opinion).

 

We haven't so far found though so far any adapter which will allow us to connect the vetus directly onto this leg (and I can't see that there would be  an "off the shelve part" as surely theres a loads of different engines?! etc), saying that therefore we where forced (well not forced as mentioned we prefer to have the engine separate).. obviously too  we are still very early in the project and open to any change to improve things and if a better way comes then we will certainly do that.. I personally am one for over-engineering and like doing things the best way even if that costs money (hence refusing to have an old BMC engine in and replacing with a newer vetus!).. I'm also not happy with an old bellhousing in place and would prefer if something replaced that.. Its just finding that something I guess...

 

But please if yourself or anyone reading this knows a way to make this better then please please advise (Have you got details of this adapter to hard couple up?). Also be assured that this boat is along way from going anywhere near the water (well intentionally) until everyone on here is shouting our praise it's certainly not going to be this year!

 

Thanks again

[Guest]

I wouldn't have any doubts about the Vetus engine Alan, at 33bhp I'd say it's perfect for Broads use in that size boat.

 

This is like a crossword puzzle you can't put down !

 

I'm still trying to research the exact detail inside the 280 leg.It's surprising how sparse it seems to be on the web.

 

I've found this cutaway diagram showing your 280 leg mounted on the engine, but unfortunately it's not very high res, so the detail is a bit blocky. I've blown up the crucial bit we're trying to understand and added a few notes to explain my deductions.

 

It looks as though what I've always taken to be a soft rubber seal may actually be a bearing covered by a rubber seal on the outside.

 

Even though that will act like a plummer block and stop the shaft from moving sideways, I'm still thinking it would be a problem.  It's only a single row of ball bearings, so it still depends on the other end being held perfectly centrally by the rear crankshaft bearings via the original plate on the flywheel.

 

Because the new intermediate shaft is now flexibly coupled, the whole lot could slew outwards with centrifugal force under load. (like a sort of skipping rope).

 

Mark is right about the cost of the Aquadrive I'm afraid, I've never been able to justify the expense for any of my boats !

[JawsOrca]

Thanks strowager.. I'm really sorry that your mind is being puzzled by this.. hopefully it's an enjoyable puzzle though!  unfortunately I haven't spent any time looking at the leg bits and Unfortunately we can't get into this yard until the weekend but i will take lots of picture and publish on here (again I'm sorry that this means you maybe thinking of this for some more time!).

 

Dave and our friend Ricky are thinking about putting a plumbers block just forward on the shaft infront of the black coupling (which is attached on the splines of the volvo bellhousing) which is basically where the volvo flywheel would sit.. although this to me looks messy do you believe that that would stop this sideways movement? I know its probably hard to tell and it sounds to me that you need more details. but what do you think? (to me it sounds like this is too far forward and getting perfect alignment would be near on impossible as we have nothing to go by?!... but If so we would need to need then work out how to dampen the wobble of the engine further forward.. but one step at a time!

 

Needless to say the invite is there to come down and take a look if you wish/can't sleep!  

[Guest]

No need to be apologise about giving  the puzzle Alan, it's helped me understand my own drive better.

 

Your initial description on how you intended to flexibly mount the engine remotely from the outdrive housing and link it with a bespoke intermediate shaft is what sparked my interest, as I'd never seen anyone try that before.

 

I'm afraid I'm now convinced that direct connection of engine to transom shield is the only practical way to go, since there are so many problems to overcome with modifying the transom shield coupling to enable it to work without the robust direct connection to the flywheel and crankshaft.

 

Have you actually tried phoning Lancing Marine and talking to them ? they do offer to make up non standard adapter plates to marry almost any engine to most outdrives.

 

If you could go back to that standard method, then the whole thing becomes so much simpler, no doughnut joints or couplings, and accurate alignment just becomes a matter of adjusting the height of the two front mounts.

 

[JawsOrca]

It's good to know that we are at the forefront of unusual engineering! 

 

I've just emailed Lancing (I think I got Tnorris and Lancing confused) I can see they do adapter plates so hopefully they can help with a direct connection. I will follow up with a call at some point.. I'll update on any progress...

[Swordfish]

Hello JawsOcra,

 

I have only just viewed this thread, my comments are :

 

The bell housing ( or flywheel cover in USA )  is a very very important part of the installation. It houses two large bearings, which support and secure the Primary Drive Shaft.  This PDS connects the engine and drive, and you CANNOT just mount it via the two rubber do nuts through the transom shield.  The bell housing MUST be rigidly connected to the engine for the drive connection to work correctly.

In many cases the bell housing has to be altered when using an unusual engine, I do have photos of this, but the method of posting them seems to be different since last time so I will post them in another reply.

 

Regards,  Paul

 

I do have a work shop manual for the 280 Drive, where are you?

 

I will post

[Swordfish]

Here are some photos showing bell housing alteration and connection to engine.

 

[JawsOrca]

Hi Paul,

 

Many thanks for your message.

 

Just to advise to all we have been talking to Lancing marine today and they are currently working out how to connect the vetus upto the sterndrive... Although its still early days in what they will be doing etc but will post updates as soon as know more..

[JawsOrca]

Thanks Paul. I've just seen your pictures.. Is that lancing marines work there? If so that looks a proper job!! (Any ideas how much that costs as they can't/won't talk money yet!) - Do you know someone else that can do this?!

[Guest]

Lancing Marine have a very comprehensive website with down-loadable PDFs of price lists and "how to" guides.

 

Here's the page with some of the prices of "off the shelf" adapter plates:

 

http://www.lancingmarine.com/pricebook2013/page21.html

 

Not cheap, but relatively inexpensive considering what's being achieved.

 

Yes, it's the only way to go really. The whole concept of a Volvo type sterndrive is that the engine and outdrive transom shield are one unit, rigidly bolted together via the appropriate adapter plate.

 

The engine cannot be flexibly mounted as a separate entity to the outdrive.