New Guts - Part 3

Mike Garside · 30 August 2002, 18:09

Well, here's some more stuff as we try and squeeze a quart into a pint pot. Believe me there's some serious surgery comin' up...

First, the small business of altering the transom opening. Not a lot of adjustment needed but the bottom of the Yamaha leg was just a few mil wider than that of the Yanmar. You can see acouple of filets and two new holes we've made...

Mike Garside · 30 August 2002, 18:11

That done, we fit the outdrive. This pic, taken from the empty engine box shows the bolt heads protruding though the transom...

Mike Garside · 30 August 2002, 18:13

On goes the backplate....

Mike Garside · 30 August 2002, 18:16

Then we're ready to lift in the new engine to see if she fits the 'ole. According to the drawings she should but....

Mike Garside · 30 August 2002, 18:19

Down she comes. Slowly slowly. It looks as if it's going to be a tight fit...

Mike Garside · 30 August 2002, 18:23

Perhaps if we turn it a bit....

Mike Garside · 30 August 2002, 18:25

That didn't work. Perhaps we should tilt it into the hole?

Mike Garside · 30 August 2002, 18:27

Well, that didn't work. Back out with the engine and to work with the angle grinder...

Mike Garside · 30 August 2002, 18:31

Then after a few serious slices with the sabre saw, in she slips. Tight, as they say, as a mouse's ear 'ole...

Mike Garside · 30 August 2002, 18:32

That's it for now, folks. More tomorrow.

Cheers....

Charles · 30 August 2002, 18:39

Hi Mike

Nice shots to keep us all up to date, quite interesting too.

Once the new engine is in and the 'running in' period has been completed, what do you realistically expect to achieve speed-wise?
Your fuel capacity will surely cover you for a good 300nm?

MarkWildey · 30 August 2002, 19:29

mmmmm...

Changing those belts will be interesting !!!

Mark

Mike Garside · 31 August 2002, 07:08

Charles, as far as range is concerned, I am hoping for 300. Originally the boat only had 1 x 200 litre tank but I have added two more bringing the total to just about 600.

As far as speed is concerned, I have no idea. Brian gets a top of 33 knots with Cyanide. Mag A is much heavier. The less optimistic advice I have had points to 27 knots.

But that is only 4 knots faster than the 23 I was getting with the little Yamaha (at 3000 revs) once I had installed the trim tabs and moved the weight forward with the new tanks.

If I get less than 30 I shal be disappointed, I have to say.

Mark, you are right about the belts. But I am working on that this weekend. I am thinking of putting a hatch into the deck over the void where I have cut out part of the bulkhead in front of the engine.

Access from the side is fine and if I can get to the front of the engine usefully through the hatch then all will be OK.

If that fails it will be a question of a quick lift out to get at the belts. That's easy in the St Mawes boat yard. Not so easy if I have to do it once I'm off home ground...

Rene · 31 August 2002, 19:49

Hi

Some really nice pictures, you really get the "picture" of whats happening

A generell question....

How do you find the right hight of the drive. If I would like to fit an inboard engine to a boat without a hole in the transom ??

You must have to think aboot both engine size (So it can get low enough in the boat) and the length of the leg..

This is to had to figure out

For me anyway (Just put this line here so I wouldn't offend anybody)

Anyway.
Keep the pictures comming

Regards
Rene

Mike Garside · 01 September 2002, 04:40

Interestin' question, Rene. And one, from a technical point of view, to which I am not qualified to answer. From a practical point of view it would seem sense to keep the engine level with the bottom of the hull and the forward engine mounts as close to the longtitudinal stringers on which they will sit.

This will then determine the height of the backplate because the rear engine mounts are attached to it. The hole through the transom is, obviously, a cut-out within the backplate.

There are a couple of very practical complications to this that we discovered in changing the short Yamaha for the longer Yanmar. You'll see that when I post Part 4 of the New Guts thread.

The keys to the alignment of the engine is the angle of the transom and whether or not it has been fitted at 90 degrees to the keel. It is also important to get the hole dead in the middle of the centreline.

It cost us half a day trying to sort that little lot out. We discovered ....

1 The transom is inclined at the very bottom of the 10 to 16 degree range which is the norm. It is at 10 degrees and this has meant, because the new engine mounts are further forward than the old ones, that we had to grind down the bearers to lower the front of the engine, which is slightly nose down in the boat. That was not obvious with the short square Yamaha.

2 When the hull was originally built the transom was not set at a perfect 90 degrees to the fore and aft line This has now meant that the engine is slightly skewed as well. Again, this is more obvious than it was before.

3 And finally, as we discovered when we accurately located the centre line of the back plate, the original engine was not mounted dead in the middle of the transom.

None of these errors has caused the boat any obvious problems in the past, so presumably it should be OK when we have changed the engine.

But it just goes to show that my Ribtec hull, strong as it appears to be, is no piece of Hitec hardware.

One final thing, Rene. You may want to get in touch with Stuart "THE WAVEHUMPER" Hopkins. He's buying my old engine and is planning to do the same thing as you.