strut pad height problem

Grady · Post by **Grady** » Sep 18th, '07, 15:35

Hello,
I am repowering and would like advice about this pad from Danny at Hightide. It's a B33. Drop and angle was off when it arrived. It did drop in the Bertram bolt pattern. Danny says it's very common to have a fiberglass pad built up underneath the strut but this pad is 1.5 inches or more.....it looks like it will cause undue drag but Danny swears it's OK. He says the factory did this all the time. To get the alignment right required this much pad. Could I get a comment about this from Capt Pat and anyone else that may have run into a similar issue. We are going to add material in front and back to smooth the flow to reduce water drag. I still am concerned that the flow back to the props may be interferred with. Pic is at http://www.scaffoldmart.com/images/Bertram2.jpg Is it fine or should I ask for the struts to be redone?

Thanks,
Grady

CaptPatrick · Post by **CaptPatrick** » Sep 18th, '07, 16:16

Grady,

Certainly doesn't look right to me... I've never seen any strut needing much over 1/4", on any boat, to fine tune the angle. Appears to me that the strut leg is way too short. If they were cast struts I'd guess that a wrong part number was pulled. But these were obviously custom fabricated, thereby, the fabricator didn't measure twice & cut once. He should have caught this from the blueprint or drawing...

I curious why the job was carried this far before getting a solution?

Br,

Patrick

Dug · Post by **Dug** » Sep 18th, '07, 16:35

I agree with Pat. That looks like the strut is too short.

That doesn't look right to me.

Dug

Carl · Post by **Carl** » Sep 18th, '07, 17:20

Either the motor has been brought way up high or that strut is way off.

Will it work, yeah probly...but to what degree. It would be like runnng with your trim tab down an 1-1/4". Could you run...sure. Could you still trim the boat...sure. Is it right...nah.

As it is a custom SS job, cut off the base, re-space, tack it up, give it a try then have shop re-weld.

ScottD · Post by **ScottD** » Sep 18th, '07, 20:44

Grady, if he says that is common, ask him to show you another like it. Nobody wants to slam a builder, but that's over the line.

ScottD

Bruce · Post by **Bruce** » Sep 18th, '07, 21:00

Question for you.
Did you replace or change the shaft log?

If you have an original strut, the dimensions from center cutlass bearing to top of strut plate should be the same.

I have seen a few with that much spacing, but it was due to bad engine placement and the struts were an after thought instead of being included in the whole repower picture.

That looks like the shaft angle is down quite a bit and you may have a problem with nosing the bow over at higher speeds.

That needs to be fixed.

Whaler1777 · Post by **Whaler1777** » Sep 18th, '07, 21:10

This is how they came when I got my boat (B31) There was a solid pad made of some red material that was on the back of the strut... Engine alignment was wayyy off for a while so much that the shafts wore away a hole into the brass shaft logs under the ruber hose that attached to the stuffing box, I will try to take a pic when I get a second... And how about the proximity of that water scoop to the prop... Duh can you say cavitation?

Sean B · Post by **Sean B** » Sep 18th, '07, 22:28

Grady,

If it helps, here is what the factory-installed struts look like on my B33

As you can see there is not a significant amount of filler between the strut and the hull.
There is a little in there to accomodate the curvature of the hull, but that's it.

I think you have your answer - you need to fix that.
But Bruce is right, it's not Danny's fault if they are the same vertical depth as the stock B33 struts.
If that is the case then something about the engine placement has to be off.

I thought the order of affairs was:
1) align/install struts to shaft logs, so that shafts are centered in them
2) align engine installation to the shaft

I remember your post about repowering from last summer on the B33 site.
Did you decide to go with 1.75" shafts, and that is why you are changing out the struts?
Are you using those titanium shafts you had?

Grady · Post by **Grady** » Sep 23rd, '07, 21:54

Thanks for the replies. The repower is being done by a Cummins dealer. Struts arrived from Danny and I was told the angle was off slightly. So they would add pad and raise the front of the pad a bit to compensate and get correct alignment. I remeasured this weekend 2 hrs away and in fairness the plate is 1/2 inch thick. These are 2 inch shafts. I know I know. Front total measurement is 7/8 inch and the back is 1 inch exactly. So the pad is 1/2 inch front and a bit more rear. Logs were actually raised slightly. Angle on the shaft in relation to the cabin is 14 degrees. Doesn't look to be any more off than Sean's shafts. Could anyone comment on the angle on a 33 if possible. So I know I am ok........ Capt Pat I do have those 31 titanium shafts and would like to donate them to the site. Let me know what to do.

Thanks everyone,
Grady

Bruce · Post by **Bruce** » Sep 23rd, '07, 22:10

If the angle was off from the original sruts, they should have been sent back.
Its easy enough to check with the old struts to make sure.

If the logs were raised that would explain the need for a strut pad.

Logs should only be changed to accomodate larger shafts or packless seals/fiberglas tubes and never should the angle or height be changed.

You need to measure shaft angle to a parallel flat plane, not the cabin.

14 degrees is getting out to the max. Prop diameter and pitch w/wo cup needs to be considered overall also.

bertram31.com

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