24' Hartley/ AYM engine bracket

Hello to all, I'm new on here and this is my first post so please forgive me if I'm posting in the wrong section.
I'm currently building a 24' Hartley. I'm looking at making a aluminium inboard diesel engine bracket that bolts on to the transom which houses my engine and out drive.
A total weight of around 850kg Inc engine outdrive and bracket. The engine is a Volvo penta 210hp d4 dph.
I came across the idea of a engine bracket whilst trying to figure out many issues I came across trying to install a fairly modern engine into what is a fairly old hull design.
The idea came from a bracket that Armstrong and yanmar manufactured a few years back and decided that was what I wanted and it solved all of my problems.
Basically I need to strengthen my transom and Hull to be strong enough for this to work.
Any help or ideas from anyone would be greatly appreciated. The first picture below is of my Hartley and the second is a photo of the bracket that I would like to build and install.
Many thanks

 

Welcome to the forum.

Given the weight for the power output, this will need to be one heftyass bracket and wisely, should be engineered appropatly. Weight distribution would be a concern as well, which is why I recommend it be well thought out professionally.

 

Thanks, yes you are right for sure, that's why I'm here hoping for help amongst professionals)). The actual engine pod or bracket would actually give more than enough buoyancy and should actually lift slightly the hull aft also giving better fuel economy.

Any suggestions on who can help would be appreciated.
Many thanks

 

Lengthening a hull is a good modification to usually come out smelling good.

But the weight of a diesel IO is so great that with the tapered stern you have to some degree made a double end boat. In the vicinity of "hump speed" squatting may be a big problem. A gas outboard would be a huge decrease in weight aft and a good option IMO. With the diesel engine further fwd and with a shaft drive better ballance would likely result. And the hull designed and built with the shape shown would be lighter than with the add on.
Another thought (probably better) is to just extend the boat from the stern. Better weight carrying capability and purchase on the water (like wheelbase on a car) should give a boat with much better pitch stability and efficient running especially at mid speed ranges.

The tapered stern in your pics would probably benefit with better following sea directional stability. But with the IO diesel I'd lean strongly to a hull extension .. from the stern.

The above is just an opinion from an experienced boater.

 

Ideally that is exactly what to do, i suppose i was looking for a easier solution without having to tare apart the stern of the boat.

on the other hand i want the boat to be strong and handle best it can.

i cant even imagine how to go about legnthening my hull, joining in a extention to be strong will be difficult.

Do you know of anyone that can advise me on this?

all the best Trevor

 

There are a couple basic approaches you take from an engineering standpoint, one offers sufficient additional static buoyancy the other not so much, though does offer anti-squat buoyancy (such as what you pictured). On this conversion, you'll want the former, which will need the help of an NA or designer. Low speed handling will still suck, but this is the nature of the hull form and pretty much unavoidable.

 

Why not a jackshaft? Advantages-
1.It would give you better engine mounting options as there's u-joints on the shaft so you should be able to raise the engine enough to clear the existing frames.
2.The engine weight is forward - where the designer intended for a conventional engine/shaft drive arrangement.
3. All you need to do is modify the transom to accommodate the required sterndrive mounting angle.

Here's the url for the kit & an installation example - Moe


http://www.volvopentastore.com/Jack-Shaft-Kit/dm/store_id.366--view_id.1228704
http://s1093.photobucket.com/user/orionboatcompany2011/media/Orion%2027/Volvo%20D4%20Diesel%20Jackshaft%20IO/DSC05886.jpg.html?sort=3&o=14

 

Moe

Thank you very much for that. Now that has certainly got me thinking.

I hadn't thought about this setup, i will be looking into it.

Thanks Trevor

 

The kit is very pricey....Maybe even upto a extra 8,000 gbp . For just the flexible coupling is 2,000. unless i could find a second hand setup this would not be doable.

 

Yes...I knew they were $$$...On the other hand compared to lengthening the hull it's likely draw...

My boats 41series Volvo diesel is the last of the mechanical "simple" ones & I love it. The common rail diesels like the Mitsubishi 4m50 3.9l in my truck & the Volvo D4 are a very different animal & between the complexity of the common rail diesels & the maintenance demands of a sterndrive. I'd seriously think outboards if you haven't bought the D4 yet...Moe