Making boats for export what would you accept for engine beds in glass ???

Engine beds for stern drive engines to be mounted onto and Ips units have a spacific details supplied by Volvo as a minimum lay up But i cant get any details on the actual engine beds as a minimum acceptable lay up so i throw the question to every one !!
What is acceptable and how would you make them ？？
The size of the engines are all in the 300 hp and above range possibly up to 500 hp as a single .

 

Do you mean the beds for an engine mated to an IPS?

 

Ask Volvo, http://www.hweiteh.com/download/b/I...poster, hull insert and engine foundation.pdf & the vessel designer for the information, re laminate schedule, your employer should be investing in specific design info. Regards from Jeff.

 

Yeah got and read all that plus the pages of laminate for the ips units but its the engine beds that the motors actually rest on top of !!!

Would you accept wood glassed over ??: Or foam shaped and glassed over with steel plates inside the glass as specified by Volvo :idea:but there is no mimimum aceptable lay up for the beds themselves ,so that is what i am asking .

 

You got it !! most motors will be 250 hp and above . not only ips but stern drive as well with mostly diesel motors .

 

Kurt Hughes had an entry in his blog on this issue and has a good looking engine bed design in composite that can be scaled to different engine sizes.

http://multihullblog.com/2010/12/marine-engine-beds-and-structure-bourne-noise/

 

Thats the idea but a little simpler does it have steel plates to drill into and tap a thread so the mounts can be bolted straight onto the glass pad
??

 

Sorry dont know all the details on the design suggest you email Kurt it may take a few days for a reply though, he is in Uganda working on a ferry project till June 2nd.

 

Oh yes there is.. In most scantling rules me thinks. In the Dave Gerr's Elements of Boat Strength anyway.
BR Teddy

 

For both IPS and Outdrives the engine beds themselves will be non thrust taking. This means they will not have to be built with thrust in mind, only the static and dynamic loads and torque.

As for steel plates in the laminate, I prefer channels in alum or steel capping the stringers and built in such a way to allow bolting the mounts. You can also use non thrust taking mounts in these applications which will isolate engine vibrations better than thrust taking mounts. Mounts will also work best when the structure is stiff, allowing them to isolate better, so don't forget athwartship bracing to stiffen the stringers.

Steve

 

Hi Steve,

Can you produce a sketch of what you mean with channels, capping the stringers? How do you attach the cappings to the stringer?

Also, when you have flexible engine mounts, do not forget to include a flexible coupling to the IPS or axle, or it will cost an end bearing yearly.

 

These two pictures are examples, not the best but what I have in my files. The "cap" is an upside down U channel that is through bolted through the stringers. The actual mount "pad" is elevated to allow thru bolting of the engine mount. This is much more secure than tapping into a steel plate glassed to a stringer.

All remote thrust engine arrangements I am familiar with, including IPS, have either U joints, CV joints or some other flexible coupling at either end of the jack shaft connection.

http://www.marinepartsexpress.com/V...MISSIONS/Connecting kit for Volvo Penta 0.pdf


Steve

 

OK, the cap is held in place with through-bolts through the sides of the stringer. That would need some provision for strength in the laminating scheme. This must be for larger engines, say 400 hp and more?

The raised mounts is a good idea, if there is room for it. Of course it causes the stringer itself to be lower, which needs to be possible, strengthwise. At least you can grind off the bolts with an angle grinder, if needed at some point in its life.