Outboard Sizing

Chris,

A long shot, but try Preloved. On occasion, not always, there are gems. Wrong size, but the price?

http://www.preloved.co.uk/adverts/show/111373748/outboard-motor.html

The owner apparently knows his limitations.

regards,

Perry

 

Thank you guys, as you advise I will hold on until I find a 9.9 high thrust/sail drive model.

 

Good day gentlemen, Im visiting this post again after some time as I have been dedicated to working away.. im now on my final stretch this time and looking forward to getting home and getting stuck back in!

Ok, so I have an outboard, a 9.8hp Tohatsu with high thrust prop and long shaft.

Here's the final hurdle (I hope!!) Using the attached pic for reference, I need to cut a section from the top of the transom for the engine to fit on correctly and get the correct level of submersion. I will need to take approximately 8 inches, or for reference, where the top section of the transom meets the visible line that you can see on the picture.

The boat is GRP and the transom is around 3/4 inch thick. What reinforcement would anyone recommend? The engine weights approx. 38KG.

Thank you for your help!

 

I have attached a very amateur paint diagram for reference

 

It does test the steadiness of the hand, doesn't it ! How much immersion are you allowing ? As in how far below water level, will the cav plate be ? It is a matter of whether when the boat pitches, the prop leaves the water, but you don't want it any deeper than it needs to be, and setting up added drag off the leg.

 

You should consider reinforcing both sides of the cut down transom, because the Tohatsu may need to be trimmed in as, the transom is probably vertical to the water.

Measure the maximum gap of the jaws on the outboard, deduct an inch & see what that gives you. Make the area of the reinforcement plates as large as you like with good quality plywood. Shape the exterior plate from top to bottom so the OB can be trimmed in. Encapsulate with epoxy resin, paying particular attention to the edges; paint to match hull & bond in place with thickened epoxy to both sides of the transom.

Good luck.

 

I doubt it would be vertical, but you need about 13 degrees ideally.

 

Agreed.

 

Thank you for your input guy's! My plan has allowed for the cavitation plate to be level with the bottommost part of the transom, this will put the cavitation plate around two inches under the water. Using my previous experience of using the boat I don't think the prop will ever leave the water on pitching.

The transom is not quite vertical, off the top of my head id say around 10 degrees.

Your idea's sound similar to what my thoughts are. I was planning to put a 3/4 marine ply sheet, shaped to the inside of the transom, glue it to the inner transom then fibreglass it in, possibly adding a knee either side for extra reinforcement. However this is not something I have experience of, so your input is very much appreciated!

 

Rather than just a couple of knees, I'd want to keep following seas out by installing something like this & kill two birds with one stone.

http://www.kbeddoeboats.com/images/600_Picture_155.jpg

 

Thanks for your input, that looks like an excellent idea! I was going to build in an internal transom so to speak about a foot and a half or so inside the boat, however i like your idea regarding protection from following seas.

 

I would be concerned that having the prop too close to the surface could become an issue at the time when you least need problems, in rough water. I think 6 inches at least, would be desirable. It depends on what the streamlining of the leg looks like, immediately above the cav plate. If it looks reasonably slippery, I would drop it down further than you are considering.

 

Mr. E,

The coastal waters around South Shields are unlike those around Australia. They can be really unpleasant & putting to sea at those times is unlikely to be an option. Right now it's 34 F / 1 C, sunny, no rain & wind at 7 mph. No pleasure in that. We wish for 70 F & flat calm. As rare as hens' teeth.

 

Incidentally, the weather here (Brisbane) at the moment is atrocious, winds 50 knots + along the coast , seas up to 11 metres offshore ! But it is around 18 degrees centigrade. Torrential rain from a low pressure system. Not entirely uncommon in May and June here.

 

That's the second one in 13 days isn't it? At Maitland station 2-58, the flood waters are kept at bay by flood gates installed for that purpose.

https://www.youtube.com/watch?v=ug3xXaJtY1o

https://www.google.co.uk/maps/@-32....m4!1e1!3m2!1sWka0nHAt7Z9oLX-ElQdEGA!2e0?hl=en

The northern inland route transports hundreds of thousand of tons of coal. The Rail Regulator had to grant special permission to stable a number of 2 km long coal trains on the mainline, as all the sidings were already occupied.