propeller size and clearance on a 33?

[M. R. Bober]

Hi,
For 33 owners, do you know what size and pitch your propeller is, and do you have photographs of your propeller & clearances?
I have been having transmission problems, and one thing I think I need to fix is my propeller clearances, my prop is too far back from the bearing.

My boat has a 2008 Universal 25XPB (25hp, 3000rpm), so the ideal propeller size would be slightly different from the original M30 24hp 2800 max rpm, but I'd be curious to know what prop other 33' owners are using. I have a 14' 9 prop.

Thanks,
Evan

As you know, now, the Universal 25XP seems to have had more than a few transmission problems on Cape Dorys (and perhaps on other vessels with short shafts). At least one other owner--with problems similar to yours--has told me that were he to "redo" his engine replacement, he would go with the Beta rather than the 25XP.

Universal, the distributors and/or the installers should know by now that the 25XP is a bad match for CDs. (IMHO)

I hope that you are well on the way to resolution.

Mitchell Bober
Sunny Lancaster, (a good place to field test your air conditioner) VA

[JWSutcliffe]

The Universal M25XP engine package is a Kubota BD902 engine, and uses a Hurth/ZF transmission. The Beta 25 is the same Kubota engine, but mated to a Twin Disc/Technodrive transmission. For what its worth, Sound Diesel sells the brand new Twin Disc transmission (which is billed as a direct bolt on replacement for the Hurth/ZF transmission) for about the same price as a rebuilt Hurth. The Twin Disc unit is rated for more horsepower than the comparable Hurth. Since most of the transmission failures in Cape Dories seems to be in 33's and not the smaller models using the M25 variants, I would hazard a guess that in the heavier 33's you are running at a higher speed/power level, and thus loading the gearbox more than in a 31, etc. If I were experiencing gearbox failures I would look at retrofitting with the Twin Disc gearbox instead of completely repowering.

[evan]

Hello,

A long overdue reply to update that my transmission problems have been resolved!

Ultimately it would seem that the combination of too much distance between cutlass bearing and prop / shaft too long, and flexible engine mounts was causing vibration that was hurting the transmissions.

In Summer 2015 I had the following work done, by a boat manufacturing yard who knows the subject well:

* replaced ZF transmission with a TMC 40
* shortened prop shaft to reduce ratio
* replaced cutlass bearing
* removed flexible mounts

As soon as I drove the boat away it felt very different and I knew the problem was solved. Before the change I didn't feel like the boat was vibrating that much, and I felt like I'd been on boats that felt the same, but the difference on this boat was significant with the new set up, it just felt a lot smoother. I haven't had any problem since and it feels and works great.

I realized I should update this post as the boat is up for sale, and a prospective owner asked about this as they'd seen the thread and wanted to know if the issue was taken care of.

http://bit.ly/2HcVLzB

I'll post a separate thread about the sale and am willing to answer any questions anyone has.

Thanks,
Evan