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df
United Kingdom
5994 Posts |
 Posted - 30 Jul 2016 : 16:26:59
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I am looking at removing the 'jersey keel' from my princess and one guy is suggesting assuming 12mm bolts countersinking top and bottom of holes and filling with thickened epoxy then matting over the inside, does that sound like a strong repair to you? Bearing in mind I will be using for fast sea work and often in quite lumpy water.
I am also thinking of removing the 2 anodes from the bottom of the hull and refitting to the transom to further reduce drag, does that make sense?
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Deano
United Kingdom
1843 Posts |
Posted - 30 Jul 2016 : 19:24:57
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Anodes need to be able to "see" the item they are protecting.... if they are for your shafts... they should be on the bottom, over the shafts.
They don't work too well around corners.
Dean - Boating on the Great Ouse.
Freeman 32 "Liberty"
See the photos http://www.flickr.com/photos/54758027@N00/ |
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df
United Kingdom
5994 Posts |
Posted - 31 Jul 2016 : 11:35:21
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I've never heard of that one Deano, I thought as long as they are electrically bonded and reasonably close they should do the trick.
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cliveshep
Thailand
1324 Posts |
Posted - 31 Jul 2016 : 15:21:47
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I assume you mean the barkeel Dave? If you remove it, and your repair technique is fine but CSM is not good for repairs in that way - better use a bi-directional cloth or a woven roving to reduce end fibre water take up. I'd plug the holes with polyester resin and glass as well, holes are non-structural so all you need to do is prevent water getting in so the usual grinding to a taper and building up would be perfect.
BUT - and I would say a big BUT - if you take that member off what will you have to deflect things off your shafts and props because that is what it is there for. Also taking the ground - you might not intend to but we've all gone onto the putty at some point - that nice steel bar that really doesn't give that much drag will protect your hull and shafts.
Likewise the anodes - keep them "in the swim" to your shafts and as close as possible to your nice bronze props. Really Dave - it's not a race-boat launched clean just before the race and hauled after, it's a working pleasure-craft - i seriously doubt you'll gain more than 1/2 - 1 knot from the excercise. Hardly worth the risks entailed.
You'd do better to keep the bottom clean, check your engines are delivering full power/max revs and you are not over or under propped and your fixed trim tabs are at optimum angle for the power/speed/hull shape.
Well - you did ask!
Finally living the dream!
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Edited by - cliveshep on 31 Jul 2016 15:25:55 |
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df
United Kingdom
5994 Posts |
Posted - 31 Jul 2016 : 17:47:45
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It's revving to max and struggling to get on the plane properly and was bought for the extra speed at sea, I have no plans for drying harbours and would probably be fine in soft mud anyway so it has to go, currently using way too much fuel as it spends most of it's sea miles ploughing at just under proper planing speed, the man at clements marine recons it should be good for 21knots with 18 knots comfy cruise with the 150hp engines, once off the props will go to clements to be scanned and re-pitched as needed to reduce the cruising rpm a bit as reduced drag will make them over rev, currently revs out at 3900rpm.
If I hit the bottom it will be the insurance companies problem.
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Deano
United Kingdom
1843 Posts |
Posted - 31 Jul 2016 : 18:27:46
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Ditch the climbing frame Dave!!!!
Check Clements lead time before parting with your props if you intend to do it mid season. My order took all 8 weeks of the 5 week lead time!!!!
By jingo the prop looks good though... they only had it for checking and it has been totally refurbed!!! Looks like new, in-fact the engineer was convinced they had replaced it with a new one.... the only clue was the back of the boss was dirty!!!
Dean - Boating on the Great Ouse.
Freeman 32 "Liberty"
See the photos http://www.flickr.com/photos/54758027@N00/ |
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cliveshep
Thailand
1324 Posts |
Posted - 01 Aug 2016 : 02:46:51
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Cannot see on your pics Dave, are those fixed tabs adjusted by bottle screw? If so maybe tweak them down a little to push the stern up?
You've got twin 150's that reach max revs? Do you have limiters on the lumps? Just wondering also if you could do with slightly coarser pitches?
Sounds to me you might well be right on the cusp for planing with your set-up and need some adjustments to prop or trim-tabs.
A bigger boat, the Moonraker 36, at 6.5 tonnes, used to power about with twin Perkins 6.354's, 115hp each naturaly aspirated or turbo'ed to 175hp. Your's ought to do a whole lot better as it is a smaller boat with more modern engines?
Finally living the dream!
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Edited by - cliveshep on 01 Aug 2016 03:36:55 |
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df
United Kingdom
5994 Posts |
Posted - 01 Aug 2016 : 08:09:47
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Those are hydraulic trim tabs, it needs then fully down to get the nose anywhere near level, as soon as I lift them a touch the speed over ground drops off, that's partly why I recon that cattle grid hanging off it's bum is holding it back quite badly, it must be messing up the whole flow across the planing areas of hull.
I'd like to be able to cruise at 17-18 knots at nearer 3100-3200 rpm and sure it should be able to get close.
Man at clements recons it should be good for 20-21 knots at full throttle, he seemed to know the hull fairly well as has came straight out with original prop fitment for the setup.
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cliveshep
Thailand
1324 Posts |
Posted - 01 Aug 2016 : 08:25:19
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No no Dave, I meant trim the tabs down more. If they are at maximum then add a yoke spacer to the ram end to give more down. Shaped like a "H" with clevis pins through the top and bottom it adds to effective overall length.
And no comment required from the coarser elements!
It is a reversible thing without even removing it - simple trim up.
Finally living the dream!
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df
United Kingdom
5994 Posts |
Posted - 29 Sep 2016 : 08:13:32
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Well it's the time of reconing now, the boat gets lifted out tomorrow and the big cutting disk comes out, bye bye underwater cattle grid!
Going to initially cut the jersey keel off in bits while partly supported by the crane so they can rechock properly while I get the mounting plates off and sort the bolt holes.
While it's out I need to repack the stern glands change the engine intake seacocks and get the props re-pitched, anyone know the lottery numbers for next week?????
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cliveshep
Thailand
1324 Posts |
Posted - 30 Sep 2016 : 01:38:41
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I'll be interested in seeing if you get the performance enhancement you're looking for.
Still think from your comments you need to look at adjusting the maximum down angle of the trim tabs so you have a little in hand even when the boat trims level. It isn't hard engineering wise to extend the end of the coupling yoke of the hydraulic ram by adding a piece in and it will give you some options once you are back in the water.
Good luck with the mods anyway.
You need weight in the bow - have you considered moving your beer stash up front and just keeping only a crate or two beside you at the helm for instant use?
Finally living the dream!
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df
United Kingdom
5994 Posts |
Posted - 30 Sep 2016 : 08:22:19
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quote:
You need weight in the bow - have you considered moving your beer stash up front and just keeping only a crate or two beside you at the helm for instant use?
Surprisingly I don't drink that much on board and don't tend to carry much, we always aim for a pub where possible and don't drink at all on sea runs.
Once in a pub it's a different matter, I know where to get good lates on the broads....
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IanM
United Kingdom
2238 Posts |
Posted - 30 Sep 2016 : 15:10:01
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Good luck with the mods, Dave. We demand piccies, especially if you cut off the wrong bits.
I'll be sure to stick a quid in the next RNLI collection box I see in preparation for your shakedown run....
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df
United Kingdom
5994 Posts |
Posted - 30 Sep 2016 : 20:31:20
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The big bits are off and it's now sat on blocks waiting for me to remove the mounting plates, a couple of the bolts had weeped a bit but all nuts now exposed ready to be undone.
That centre rail was 8mm wall thickness and bloody heavy, only killed 3 9" disks though.
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df
United Kingdom
5994 Posts |
Posted - 02 Oct 2016 : 13:43:34
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Mounting plates now off, I weighed it at about 90kg of scrap stainless steel not including the bolts/nuts.
Apart from some reshaping around the front mount the rest look pretty good underneath, the front one has had some building up done probably to act as a sacrificial wear pad just in front of the bar.
Looks to have been painted with gelshield before putting the mounting pads on as it's green under there.
One of the guys at the yard said it should improve my mpg so I pointed out that a 1mpg increase will be close to double what it's doing at full throttle now.
Hopefully get up there next weekend and get the holes filled and hull smoothed, will probably brush a coat of epoxy over where the plates were before antifouling.
Timing was good as anodes have completely gone so I guess I have some stray current going through the bonding, could be the ferryhouse's electrics as I often plug in there, may take shore power earth out of the bonding circuit.
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Deano
United Kingdom
1843 Posts |
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GRP question for Clive
