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GILow · 02-02-2015, 19:01

Hi Cruisers,

I have just finished fitting soft engine mounts to our engine, which was originally hard mounted. Call me a a whimp, I just could not handle the vibration and noise any longer.

Now I need to be sure that the 450 kg monster stays in the same position if we get rolled. There seems to be a number of ways of solving this one, from steel angles over the engine mounts, to chains, rope, sky-hooks, fairy dust... I simply do not trust the soft mounts to support the weight when upside down.

Does anyone have a preferred smart way of solving this that they can recommend? I am likely to be able to fabricate anything required for the job, the new engine mount brackets proved to be reasonably straight forward though I had to farm out the welding after tack welding the bits in place as my welder could not handle the 12mm plate.

There are four mounting points, the front two rest on a timber stringer running transversely, the rear two rest on lengths of angle running fore and aft, which are bolted to the original engine bearers. Everything is fabricated from 12mm steel plate or angle. Weight distribution feels about 45/55, with a bit more weight at the rear.

Ta,

Matt

deblen · 02-02-2015, 19:29

Engine Torque Straps

These are used on racing cars.

I used chain on my boat.Three of the mounts had broken rubbers,& are very flexible.As I had to replace them,I decided to put a chain limiter over each mount.No pics-boat covered for winter.

You could use ss cable also. / Len

**Jim Cate** · 02-02-2015, 19:38

Matt, if the physical setup is such that you can run a loop around the critical bits, I'd consider using a soft shackle at each mount. We have s/s cable with Nicopressed eyes and a small shackle, but they are awkward to access to unscrew, etc. The soft shackle would be easier in our case... and plenty strong if made from 4 mm Dyneema or greater.

Jim

sanibel sailor · 02-02-2015, 19:52

Quote:

Originally Posted by deblen

Engine Torque Straps

These are used on racing cars.

I used chain on my boat.Three of the mounts had broken rubbers,& are very flexible.As I had to replace them,I decided to put a chain limiter over each mount.No pics-boat covered for winter.

You could use ss cable also. / Len

Real race cars use solid mounts.
I like the idea of a strap bypassing the rubber. Remember dynamic loads can be many times the static hanging load.

GILow · 02-02-2015, 22:08

Hi guys, thanks for the ideas.

Not so sure about the hot-rod engine thingies, interesting though, a good way of controlling excess movement if it was a problem.

Chains seems a popular option, and I have seen a few boats with that setup.

I wondered if there was some kind of strap that was suitable... just easier to attach I suppose.

Had not considered SS cables and eyes... Jim, I am thinking about the difficulty of undoing the shackles that you mentioned and the first thought that came to my mind was... "why would I ever want to undo them?"

Sure, I did just remove the engine in December, but that was the first time it has moved since 1986 and I HOPE the last time for many more years. I'd be happy to sacrifice the odd SS cable and swage for the sake of simplicity and reliablity. Or am I missing something?

Matt

Neptune's Gear · 02-02-2015, 22:36

I use Dyneema Loops...

GILow · 02-02-2015, 22:59

Quote:

Originally Posted by Neptune's Gear

I use Dyneema Loops...

In soft shackle format as Jim has suggested?

Matt

**JPA Cate** · 03-02-2015, 00:08

GiLow,

If I understand correctly, Matt Paulin's loops are spliced in place. The soft shackles are made up first, then installed, and may be removed.

Ann

Neptune's Gear · 03-02-2015, 00:17

Yep, spliced loops, as Ann said. They go through the engine mounts before they are bolted to the engine. No way could the engine move more than 20mm (about) without breaking the loops. 20mm is good - it's a saildrive.
Matt

**Jim Cate** · 03-02-2015, 01:10

Quote:

Had not considered SS cables and eyes... Jim, I am thinking about the difficulty of undoing the shackles that you mentioned and the first thought that came to my mind was... "why would I ever want to undo them?"

Well, that's a reasonable question, Matt! And to be honest, in the 12 years we've owned I-2, I haven't had to undo them... but I've looked at the scene and imagined groveling and swearing a bit if I did have to. And of course, in your case, you have to install them, and I'd reckon that in our case, that would be hard too.

So, the nice soft soft shackles look good to me: easy to make, inexpensive, easy to do up and undo at arm's length, no meat hooks ever... good stuff!

Cheers,

Jim

GILow · 03-02-2015, 01:21

OK, really glad I asked.

So, two good suggestions, some form of Dyneema lines vs SS cables with thimbles. Both within my technical skill set, a little bias shown here towards the Dyneema, so looking more closely at that option... a question springs to mind.

How does the Dyneema fair in the somewhat hostile engine bay environment?

I would say our engine bay is about average in terms of cleanliness and dryness, that is to say, it is mainly clean and dry, well clear of the bilge, but from time to time there are going to be small leaks, splashes of oil maybe, a drip of diesel escaping here and there. Plus all the horrid heat and fumes of a decently maintained 30 year old diesel doing its thing.

How does Dyneema hold up to that sort of thing, or how often should I plan to replace the loops? (however they are formed).

Matt

SimonV · 03-02-2015, 04:31

I am really surprised by this question and the answers. Surely the engine mounts would keep the engine secured, if not they are not suitable for their designed task.

Sent from my GT-N7105T using Cruisers Sailing Forum mobile app

**HappyMdRSailor** · 03-02-2015, 04:47

Wowsa... Wonder how I ever missed this thought????
(securing the upside down plant)

The soft links/shackles seem a good popular route...

Wondering how simple the SS angle plate might be too??? You could make them say 1/8-1/4" clearance over the mounts, and you would be less likely to tear mounts inverted and bouncing about???

**HappyMdRSailor** · 03-02-2015, 04:52

Quote:

Originally Posted by SimonV

I am really surprised by this question and the answers. Surely the engine mounts would keep the engine secured, if not they are not suitable for their designed task.

Sent from my GT-N7105T using Cruisers Sailing Forum mobile app

Simon... Mounts are designed for dynamic torque forces of the engine while in a relatively "stationary" position... IN COMPRESSION... Pure tension plus huge dynamic loading??? I don't see a lot of mounts staying intact... Let alone super soft mounts...