I/O (Sterndrive) Conversion to Outboards

[dingbat]

Some years back I considered buying a Shamrock direct drive inboard, these have the Keel Drive system where the prop is protected by a beefy keel, didn't buy because engine access was actually quite bad (probably could have been improved with some reworking of the opening in the deck) and the ones I could find needed a lot of work. BUT, simple SBF engines, Velvet drive transmission, very simple machines.

A 26' Shamrock made the short list when I bought the Grady years back.

Diesel, great fuel efficiency with a trolling valve but the speed........would have to leave a day earlier to get there on time

 

[Scott Danforth]

probably the simplest marine propulsion other than a sailboat!

Nah......

 

[tpenfield]

Life was so much simpler when I had my sailboat. . . . of course it took all day to get anywhere.

I do like my boat . . . just wish it had outboards. I will sit tight as I gather more information.

My boat is rated for 700 hp . . . so twin 350's . . . 300's would probably be fine as well.

Still getting info from Cruisers Yachts. Sort of comes in bits and pieces.

 

[Scott Danforth]

I/O boats have no HP rating

 

[tpenfield]

I got a bunch of drawings and some pictures of the hull ( outboard version) during assembly from Cruisers Yacht.

The bracket is from Armstrong Nautical, looks to be custom. They gave me the part number.

They said that I would probably need to take the top of the swim deck off to install the reinforcements. So, the task is now seeming to be taller.

Plan B ?

 

[alldodge]

They said that I would probably need to take the top of the swim deck off to install the reinforcements.

Chainsaw will make quick work of that

 

[flashback]

Did CY say what the reinforcement would consist of. That could possibly be a major task.

 

[tpenfield]

Did CY say what the reinforcement would consist of. That could possibly be a major task.

yes, they sent me pictures.

 

[tpenfield]

By the looks of it, they hired a Naval Architect firm to help with the design, based on what I am seeing in the drawings.

 

[tpenfield]

In other news . . .

My boat registration sticker arrived today . . . and . . . I got my truck back from the shop after a $6,400 brake job and tranny work. (ouch . . . )

 

[Scott Danforth]

Which naval architect?

 

[tpenfield]

Which naval architect?

Sent you a PM.

 

[tpenfield]

Did CY say what the reinforcement would consist of. That could possibly be a major task.

They sent drawings and pictures, so I can understand the differences in the two versions. (I/O vs OB).

The key thing with the CY 338 is that the transom is inset 44" from the edge of the swim deck, whereas many other boats are inset about 30". So, 44" + 'mounting well' (nearly 60") is a bit much of a distance to hang a bracket. Thus the CY 338 outboard versions are notched in about 15" into the swim deck to make the bracket design & mounting a bit more feasible, in addition to preserving the balance of the boat near its intended location.

So, my take-away from the information I've gathered and reviewed, an OB conversion of the CY 338 is not as straight forward as many other boats.

 

[vroom ZOOM]

Just wanted to jump in here and say that you will probably loose axius. Merc dealers are often very reluctant to install joystick piloting on repowers, its mostly on new boats. Besides, if your outboards aren't going to be installed exactly the same as in the factory version, you will need a new vessel personality file, and only merc engineers can develop that. However, you could add seastar optimus 360, but budget another 20k for that.

 

[tpenfield]

Lots, to think about.

In the age of low-tech boating an OB conversion would be much more straight forward. With the hi-tech systems and controls, it is another story, so it seems.

I did get a follow-up email from Cruisers Yacht saying that they had not done a conversion to outboards, but are willing to provide assistance. Not sure what that means, but we shall see.

Meanwhile, I discussed the prospect of 'needing' to get a different boat with my Financial Controller/Admiral. Perhaps we will go look at a couple of boats over the next few weeks.

My short list (used) is looking like:

• Boston Whaler 320 Vantage
• Sea Ray 310 SLX OB

My preference would be the BW, but the Sea Ray may be a consideration from a price perspective. Not sure if I should consider any other brands/models.

 

[Scott Danforth]

Meanwhile, I discussed the prospect of 'needing' to get a different boat with my Financial Controller/Admiral. Perhaps we will go look at a couple of boats over the next few weeks.

Be leery of signing any paperwork..... pretty sure the admiral is upping your life insurance and watching movies on HLN (Homicidal Ladies Network)

 

[Lou C]

It’s like modern vehicles…integrated fuel, ignition and wiring systems make modifications a lot more difficult. That’s partly why I kept the old boat this long. It’s big enough for my use in local bays, small enough to store at home saving a ton of money each year, easy to tow etc. options for repower are also wide open, another V6, or V8, can keep the old Cobra drive or upgrade to the Volvo SX (Cobras can pretty easily be converted to the Volvo), etc. For now the old original V6 that got a top end overhaul 7 years ago is doing fine & that old Cobra shifts just as well as the late model Alpha in my brothers 2020 Chapparal. So for now, keeping it…

 

[tpenfield]

Be leery of signing any paperwork..... pretty sure the admiral is upping your life insurance and watching movies on HLN (Homicidal Ladies Network)

Yup, I got to get the Admiral 'on-board' (S-T-S) . . . I'm using old(er) age to my advantage. When I bought the CY 338, I didn't think the I/O maintenance would be too much of an issue, but the amount of normal effort is catching up to me.

I've compiled a list of possible boats . . .

• CY 338 OB - Wicked pricey - probably too much.
• Saxdor 320 GTO - Wicked expensive too.
• BW 320 Vantage - Would be my favorite
• Regal 33 OBX - My second favorite
• Sea Ray 310 SLX OB - Smaller boat than my current, lots of seating, might not cost too much to swap-out.
• Robalo R317 - Good seating layout, May not cost too much to swap out.

Anyway . . . We may be able to look at a few.

 

[Scott Danforth]

Ted, for the $150k conversion, you could pay someone $5k per year to do the maintenance for the next 10 years and sell it to come out ahead.

 

[alldodge]

Ted, for the $150k conversion, you could pay someone $5k per year to do the maintenance for the next 10 years and sell it to come out ahead.

I really like that thought
I could go back to I/O's but only down side is multi-winterizations