Trojan Boat Forum

Hi All,
This Damn boat dropped into my lap last June. I had no intentions of buying her.
The owner had heart issues and needed her togo, his wife told my wife about her.
Now mind you I have a 96 Carver 310 twin 383 strokers with less than 20 hours. My wife said never again!!!!! Carver was in bad shape when I got her.

I had 3 weeks to get her out of Herrington land storage. After sitting for over ten years.
Repacked shafts rebuilt carbs , Sanded painted bottom and polished{no damn pressure washers allowed} to take off ten plus years of oxidation.
She started right up! Guess she wanted out of there. I keep asking myself.
Why Why do I deserve this vessel.........
My Carver sits as my condo next door to this beast since July.
But she is a PIG rides like an old Cadillac and drinks more. So I am on the road to repower her.
I have been lurking here for a bit pulling bits of Knowledge.
I now have 2 315 Yanmars No emissions {National security waived Coast Guard pull outs} Sitting on a trailer calling me .................
Again why why do I deserve this vessel.....
I have lots of Questions some answers.....
Just putting my toe in the water here, but I think I am up to my neck!
My first questiion ! Can I use 2.04 gear ?
Frank
Chesapeake beach MD

I'm wrapping up a repower on a mid cabin myself but gas engines. RWS is your guy with Yanmars, I'm sure he'll have a lot to add. His is an express though, not mid cabin.

The biggest issue I see with Yanmars is can you get enough prop under the boat with 2 to1 gears. Do you know the Yanmar model? Or the Rated RPM? if you do I can calculate prop sizes .

They are 6lpa rated 3800 rpm. My concern was prop size as well as shaft. I have 1 1/4 now. I beleive the cutlass bearing can be changed to 1 3/8.Thanks btw all.

The EXPRESS setup is far different than the MID CABIN

Have you confirmed these will fit re: height, width and shaft angle?

These engines are taller and longer than the factory 454's

We used downangle ZF gears

On the EXPRESS the shaft between the trans & shaft log is a good bit shorter

The beauty of this is that while the engines are way taller, you have lots of space all the way around for maintenance, filters, zincs, etc.

We added a pair of aluminum plates (one each side) to the top of the stringers to spread the torque over a greater area. Since mine are essentially hollow except for the original motor mount spots, these aluminum plates were through bolted AND 5200 bonded to the stringer

The drawback on the express is with the engines are farther forward, the shafts are long and there are two struts per side

With your shorter shafts, you may be able to use the factory shafts, or simply upgrade to Aquamet 22's

Lots more re: fuel filters and such

Suggest you get a REVERSO or similar oil change system, additional sound insulation and engine room lights while the engines are out.

I have one concern for you, and that is the existing gasoline genset.

I love my Yanmars and wish you great success.

RWS

There seems to be ample room. Centerline is same distance to mounts. I used top of mounts to measure for height. I had 4 inches more height stated from yanmars specs. I assume your using 1.55 gear, I seem to remember 18x20 propeller. With the ZF gear you just need the correct SAE ring? I was looking at the Kanzaki kmh61a as they can take the power and are light. I found a pair of 2.04 for a good price on eBay.
The genset is in the middle of the very back out of the way of everything. I was going to just disassemble and dispose of it. I don’t think anyone would want it.
Also what size shaft are you running? I put aqualoy 22 in the carver they were 700 each 1.25 60 something inches long. Carver had severe Galvanic corrosion. Struts were Pink!
Bob you did the 8.1 repower correct? I was thinking that route as I had a crash course on the Mefi. I was also looking at the 6bta option. Saw the yanmars specs and said hmm.
Prowlerfish that would be great especially if you could tell me the difference in prop size 1.55vs2.04.
Thanks all

1.5 to 1 recc 18x17 can use 17x18 ..............2.0 to 1recc 21x23 could us 17x27( ???) all 3 blades You need to check clearance.

This is a rough calculation don't order your props yeat lol

please keep in mind this info applies to a 1983 EXPRESS - not a mid cabin

TROJAN 10 METER (33') INTERNATIONAL
PUBLISHED WEIGHT 12,500 DRY
ACTUAL FULLY LOADED WEIGHT 18,000
TWIN YANMAR 6LP 315 HP TURBODIESELS
ZF63-A DOWNANGLE MARINE GEAR 2;1 RATIO
GEARS ARE NOT MATCHED
ACTUAL GEAR RATIOS:
PORT = 2.04:1
STBD = 2.1:1
MICHIGAN NIBRAL 4 BLADE PROPS
HJ739 20X20 R4 1.5" BORE NO CUP .0.72 DAR NIBRAL


As we speak, I am in the process of changing out the props.

The ole girl has gained some weight over the last 15 years.....


RWS

I have a pair of 17x19 3 blade 1.25 cupped on the Carver. Rob Peter to pay Paul. Could be done , but no rush. Summers here rather be floating!Plus have a 5 month old pup, big girl 75 lbs lap dog.
I’m not sure on biggest diameter prop I can swing . Would like 4 blade.
Currently 16x15
RWS chimes in as I am about to post ! He’ll post it anyway.
Thanks you guys! Glad I stopped Lurking.

I have 18x20, four blade which is the largest diameter you can swing. I’m actually a bit under the prop/hull clearance recommendation of 15%, I believe 12% was my final number.

I adjusted the tachs to the “real” numbers and went for a cruise last night. Verified by the ECM output:

3,400 19.1k 28gph
3,600 21k, 30gph
2,800 14k, 20gph

I have a couple of more hours of break in run time, oil change then I’ll see what my WOT looks like. Depending on how you look at it, I have a feeling that I’m propped correctly. Doing the math with tach issue, I think I hit 4,800 already although that wasn’t the plan. I think when it’s all said and done, I’ll be cruising in the 21k range. Maybe the props can be tweaked and I can pick up another knot but would do that in the off season.

Bob

I think I need to adjust my calculation inputs looking at RWS's prop numbers as they are real-world need to change hull type I believe

Today's low displacement/high RPM diesels will live long lives with proper maintenance and CORRECT PROPPING

Any diesel will suffer premature wear and, yes Virginia, early death if overpropped.

Suggest taking your time with prop choice.

Call in the experts.

It will surely pay dividends in engine longevity, power & economy

RWS

The experts Can only get it as close as the info given. I redid the calculator changing too slow planeing from avg. the recommend props were what RWS is running. I was very surprised.


Using the same hull 1,5 gear and 16" dia !6x17 3 blades 16x15.5 4 blades both cupped.

RWS you are running zf63 I didn’t think they were strong enough to hold that much torque. I am in no rush but would like to get the gears in the next month.
I am at the boats now redoing skylight windows.
My main curiosity would be the pros and con 1 .5vs 2.0 gear.
Bob states I can only swing an 18 “ prop. Bob did you just change props or shafts too? Prowlerfish what’s the rating on your 6bta’s?
Also Bob what cpu are you running?
Thanks,
Frank

Also the motors I bought were originally stern drive, dampener plates are all the same correct?