Motors in YEA!!

[DCJ]

https://Imgur.Com/a/ExLOio7
Big day, motors are in. So here is where I’m at. I went by the book trying to change shaft angle to the magic 12 degrees and the only way I can make it work is by moving shaft strut aft by 2”. Then everything lines up, shaft coupler to trans output shaft, shaft to strut, etc. This is rough shaft alignment but I feel it is close enough so I can get a shaft measurement, order shafts and set shaft logs along with final alignment. As photos show boat is dead level off of stringers, motors are down 2 degrees plus 10 degree output shaft equals 12 degrees and so on. (Spoke with Jason and he said he got there leaving struts in original location.) So, I laid out prop location on shaft, rudder clearance etc., and it looks to me like I will be able to turn a 20 -21” wheel and be within tolerances. Any comments, suggestions or warnings?

[DCJ]

Tech difficulties in image posting stand by

[DCJ]

https://www.flickr.com/photos/198996996 ... 526e942RL1
Images at last, amen.

[Carl]

In my eyes the biggest issue with moving the rudder aft is you lose the room to change your props. I’d be lousy having to drop the rudders each time you want to pull them.


If you bumped the angle to 12-1/4 or 12-1/2° that should put the strut in original location, no? Maybe trim a little off the end of the strut base plate will squeeze a 1/4” or so for you as well.


I am not sold on 12° being the magic number, I think it’s more a case of the less shaft angle the better…but it becomes a compromise at how far your willing to go to squeeze out every ounce of performance gain. Is a 1/16th of a knot gain worth the aggravation of pulling the rudders to change the wheels?

Looks great, congratulations on getting to this point.

[DCJ]

Hmmn, great points you make Carl, the prop swap would definitely by a bummer, will regroup and tweak some more. Thanks

[Tony Meola]

Have you had the new struts fabricated yet? If not adjust the design so you can leave them in the same place the originals were.

[Carl]

I believe David is using existing struts, boring out for 1-1/2” shafts.


Another thought…ask the machine shop to tweak the bores angle in your favor. It may only be a few hairs they can do…but a few hairs over 90” or so can make a difference.

If they say no, I can understand why as it makes a relatively ez job a bit more interesting. AND I do not know how much meat your strut barrels have…if thin, I’d leave straight.

[DCJ]

Yea Tony, that thought crossed my mind, till I priced them, and may eventually come to that. I’ll find out when I get everything to machine shop. Carl, miked the barrel and it ranges from .234 to .260 wall thickness, old cast bronze struts are pretty rough, IYO is what you’re suggesting doable? That along with having to cut down dia. of cutlass bearing as well it may be money well spent to just have new struts fabed?

[DCJ]

BTW, Got the strut back to original location and still am in the 12 degree range. Don’t ask me how it worked but it did. I’m beginning to think my problem is I’m trying to turn boat building into rocket science. Anyhow thanks for the help.

[Carl]

BTW, Got the strut back to original location and still am in the 12 degree range. Don’t ask me how it worked but it did. I’m beginning to think my problem is I’m trying to turn boat building into rocket science. Anyhow thanks for the help.

You hit the nail on the head, it's not rocket science, there is a good amount of latitude. When you softened up to allowing a range instead of a hard number things lighten up, flow, and fit better...its a Zen thing. Hmmm, maybe the Zen thing went a bit too far. LOL

What I said about tweaking the angle of the barrel when boring open to a larger size is definitely doable, but with only a 1/4" wall to work with I think that would be asking for problems. Trimming the base plate back a bit would still be on the table in my opinion...but that no longer seems necessary as you are in that 12 degree range.

[DCJ]

Next dilemma, moving forward with ordering shafts and wheels. Plan is to order blank shaft stock 14’ pce. In Aqualoy 22 and have local machine shop build them. Machinist is wanting wheels and shaft couplers for machine fit. So without doing extensive search on this site, does anyone have experience running 300hp 6BTA’s which are the 1990 older Cummins and will be treated as 250hp for longevity. Shaft angle is 12 degrees, boat is SF converted to FBC. What size wheels ? I am not a speed freak and the truth is most days offshore in Deep South Texas you’re not going to enjoy the ride over 25kts. I’m into decent cruise with the best fuel eco, 4kt +- trolling speed, with good response/low end and don’t want to look like I’ve been “Overserved” backing into my slip. All feedback appreciated. Thanks

[bbtiller]

See my post dated 26 August 2020. I had a 31 w/6bt 250s. I still have a pair of those wheels if you want em; for 11/4" shafts.

[DCJ]

Thanks for the reply Brad. Read the entire thread, sounds like you had a lot of nat sayers till you posted the pics. Pretty impressive. Did you ever calculate your GPH at cruise? What was your low idle speed? And on the prop offer don’t know if that will work as I’m running 1 1/2” shafts. Thanks again.

[Tony Meola]

I believe when Bob Lilco did his repower, he had struts made to adjust the angle of the barrel, so it all conformed to 12-degree angle.

I have the 270 Cummins, which is the 250 somehow juiced up a bit. I run a 20x 23 prop with cup to the blades. You can go as high as 21 inches and take out some pitch. The wheels should be almost square since that seems to work the best for these boats running the 250/270 HP engines. Depending on how much weight you carry, your cruise at 2200 RPM's will be around 23 to 24 knots. Once I drop down to half a tank 26 knots is not unheard of.

I was real light two weeks ago, with about 60 gallons of fuel and was easily hitting 26 knots and had room to go. But in all honesty, not something that I try to do. Most times 19 to 20 knots make for a comfortable ride unless you have a really flat ocean. I tend to push it more once I am back in the bay heading home since it like driving on the Garden State Parkway, if you aren't doing 80 you take your life in your hands with everyone cutting you off. But the bay being the bay, shallow and busy, sometimes the ride in the Ocean is better than in the bay with the short chop.

Good luck in moving forward.

[DCJ]

Thanks Tony. So with those cruise numbers in mind offshore would you consider your boat loaded/heavy?

[DCJ]

And do have any idea regarding fuel burn?

[Tony Meola]

I am light. I weighed 12,000 lbs full of fuel last time I was on a lift with a scale. Burn is around 15 gallons an hour give or take depending on weather, tides and wind. I find the Bimini top creates a huge drag. Put up an encloser and forget about it. I run without an enclosure. But as I get older, I don't find getting wet fun.

Those days of getting soaked from spray on a 4-hour run home from offshore is not my idea of a good time. Getting caught in a heavy run running bothers me more than getting a wave in the face. When I was 25 it was just part of the fun at 72 not so much.

[Carl]

You r light Tony...

With the 440's and 162 gallon tank I was told she's 14,000lbs. Changing to the Cummins with 220 tank I assume she's heavier. I've checked the weight but forgot to remember.

[bbtiller]

-Don't know that I calculated the GPH but I burned about 120gal running 120mi round trip fishing offshore. Trolling for 6-7hrs.

-Idle speed both in gear, right at 7kts.

-

[Tony Meola]

You r light Tony...

With the 440's and 162 gallon tank I was told she's 14,000lbs. Changing to the Cummins with 220 tank I assume she's heavier. I've checked the weight but forgot to remember.

What year is your boat? Boats built after 73 are lighter. They made the hulls thinner due to the price of oil. They found they could thin them out without sacrificing strength.

[Carl]

My boat is a 62

[Tony Meola]

Carl.

Your hull is thicker than mine. Year's ago a family friend had a 68 fly bridge with the lower station. It road c completely different than hours do to the weight difference.

[Carl]

I have a feeling the extra weight keeps my performance on the lower side of the scale when comparing boats with similar motors. Then again I do not push the boat unless needed, or just one of those occasional make sure everything runs as it should push for a short bit.

I think mine also has additional strakes. Not sure how they change the performance...if at all.

[Tony Meola]

Carl

If memory serves me correctly, I believe Bertram said they found no difference between the early boats strake layout and the newer ones.