Twins to single - elephants trunk and max weight

[tom020780]

Right I have a old school tornado 5.5m that had twin 60hp Mercury elpto's one died so just removed engines and about to buy a single.

Weight wise the boat is rated for 180kgs - 190kgs so I have been looking for a yami hdpi 150 or a optimax 150.

Just about to buy one or the other and was stripping off the old outboards and realised 2 things

1) lots of holes in transom that need to be filled (old engines also have locks on bolts for securing)

2) elephants trunk now in the way


So I have a frp company and a couple of laminators so I can get these filled but a little worried about outing a 187kg lump on the back and the transom postage stamping and failing when under load.

I can obviously get a bloody good hole repair on the old elephant trunk hole but still a little worried

Anyone got any experience or advice???

[hamster]

You could consider a stainless plate to give a bit of reinforcement across the holes. Could do one to cover all holes but should be ok with one across the top engine mount holes where there is more load say 6-8" deep. Get a fabricator to make it up for you and they can drill holes in required places. I had one made up that had a 2" lip bent over to fit over the top of the transom. Makes the plate stronger and protects the transom. 4 or 5mm stainless will be fine.

Ensure holes are filled with epoxy rather than polyester resin. Stronger and more waterproof.


RYA Instructor, Trainer, Examiner and Skipper

[tom020780]

hamster


thanks for the reply, yes epoxy all the way. have spoken to one of the laminators at work this morning turns out he used to build FRP boats and repaire them, he has recommended to router out around the hole approx. 6-8mm deep and about 50mm both sides, use a plug cut on the cnc on a 16mm solid laminate plate that we stock then epoxy resin and glass staple paste to back fill then laminate over the hole and recess routered out.


Was thinking about a stainless plate to cap it all off and add the sleep at night factor - good thinking


tom

[hamster]

Photos of plate I had made here

http://www.rib.net/forum/showpost.php?p=441767


RYA Instructor, Trainer, Examiner and Skipper

[tom020780]

nice thanks for that will have a word with the metal fabricator down the road later today

[Searider]

Stainless plate is a bodge when you don't have the facilities to do the job properly.

That's a huge amount of power for a 5.5m boat - both of those engines will be over 190kgs too.

[tom020780]

have facilities to do it properly just want to make it belt and braces as agree its quite a weight, the existing pair are being replaced with a single.

existing 60's weighing in at 90kgs each (was quite shocked when put on the scales) so the weight difference is negligible. as its the original 5.5 from tornado its got the 25'' transom and is quite a bit beamier that the newer models.

have had a look at a couple with 125's and 150's (all two stokes opti and e-tecs) that have been in service for a few years without any issues and seem to get along pretty well.

single 90 was pretty unimpressive as its pretty heavy especially with 150l of fuel under console.

then again always open to suggestions as decision not made, have a yami 130 to go and view over weekend as an option.