Need Info on Building New Engine Beds

[bradley1968]

Hi,

I'm in the planning phase of repowering my 30' sailboat with a 3YM30, and would like to replace the existing engine beds, also adding a thrust bearing support plate for an Aquadrive. I'm having difficulty finding information on designing, constructing, and installing engine beds. Can someone please point me in the right direction?

Thanks,

Brad

[mydauphin]

After many years of building them - I find Aluminum is easiest, strongest, longest term solution. Find yourself a good mig welding shop, mine charges like $50 - $100 to weld some simple stuff. Cut the pieces to size with a 24+ teeth circular saw blade, You can buy 5000 series aluminum from distributor in 4 or 6 inch wide, 1/4 or 1/2 inch bars and cut and weld to size.

Stainless Steel is really expensive, and aluminum last as long if you just paint it a little with zinc chromate primer and a some spray can paint preferably epoxy.

Hope that helps

[bradley1968]

Hi,

Thanks for that information. Any advice on how to create a template for the beds and then fit and mount the beds to the hull after fabrication? I'm planning to remove the old beds down to the stringers and build a new bed platform around them, taking the longitudinal members back past the shaft log to increase rigidity/decrease vibration. Do you glass in the aluminum beds to the hull?

Thanks,

Brad

[mydauphin]

I cut the pieces and spot weld them in the boat exactly how I want them.
I made have a portable mig welder (readywelder.com) that uses two car batteries, and a argon tanks. I then take the whole thing to welder to really do it right. (You could also try to stick weld it with Aluminum coated bar and two batteries, it is just to hold them in place. Or have a friend with a mig help you. Make sure you get ride of any flammables in engine room and cover everything with blankets.

AS far as attaching to boat, or should I say stringer. I used stainless steel bolts, depending in size of motors. I guess you could extend cradle to include other parts like rudder mounting. The ideas is that wood and fiberglass are not very stiff, aluminum is. However care must be taken that Aluminum is mounted to a strong wood stringer that is properly attached to hull. So think of Aluminum as a brace to wood stringers spreading the load, it cant replace stinger on a fiberglass boat. The aluminum would break the fiberglass if mounted directly.
I have also used aluminum plates to reinforce the transom in some boats.

I hope this answered your question.

[MMNet SEA]

Hi Bradley,
Have you considered using a hardwood to form new bearers for your Yanmar engine ? The engine + transmission with oil and water weighs in a little over 300 lb.
The mountings are set out equally in a rectangle at the same height - these have to sit on bearers that allow clearance under the oil sump (pan) - height of the bearers around 6" to give 1.5" clearance for cleaning etc.
Aluminium with Stainless Stees nuts and bolts requires additional thought about corrosion .