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Old 31 October 2017, 21:59   #21
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Originally Posted by Callum Stewart View Post
We started in a Humber 5 metre Assault as a dive boat & it was fantastic very well made. Over 20 years ago. We then moved to a Redbay 6.1 C/W 150hp Johnson GT it was the Subaru Impreza of RIBs!!! Two years ago we down sized from a RB 11 to a Humber Destroyer 6mtr C/W 125hp Optimax. Build quality was OK but it had a list due to prop torque & the transom angle is 18%!!! Please donít trim fully in when leaving a marina in ruff weather as I did only for the over angled engine to dig deep with me & the wife thrown onto the tubes!!! Humber D = Fiat Panda of ribs. Transom angle should be 13/14 degrees.
easily fixed by fitting a stroke limit on the trim ram? if it bothered you that much. was the engine offset to compensate for the prop torque?
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Old 01 November 2017, 18:01   #22
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Poly / jwalker - would you be happy with a new turnkey RIB package only to be told by the manufacture that you should never trim fully in & the list is water in the hull. Then for a naval architect that is a specialist in RIB design & build to inform you that an outboard motor should be on a 12/13 degrees transom angle. Poly as the 18 dta you can over the trim the RIB thatís why Humber say never run fully trimmed in.

Breezeblock - Engine was offset, a set of transom wedges to bring the engine to the correct angle and trim tabs would have been the way forward but we decided to sell it at the end of its first season.

Current boat is back to the way a boat or RIB should handle leave marina with engine fully trimmed in, if sea is rough leave engine trim, if is sea is calm trim out, a fantastic made boat & engine package.

Thatís me out on this thread.
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Old 01 November 2017, 19:44   #23
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Originally Posted by Callum Stewart View Post
Poly / jwalker - would you be happy with a new turnkey RIB package only to be told by the manufacture that you should never trim fully in
Well Iíd probably have sea trialled one first so been aware of it, and Iíd probably want to understand why the transom angle had been designed that way. Rarely do you want to trim a rib fully up so why not provide the helm with a wider range of options - unless you expect the helmsman to be disconnected from what is going on around him. The optimal trim is a mix of load, boat, weather/waves, engine size/revs, speed etc. Never use? Or Never trim fully down and then hit full throttle into the back of a wave.
Quote:
& the list is water in the hull.
a new complaint you forgot to mention before!

Quote:
Then for a naval architect that is a specialist in RIB design & build to inform you that an outboard motor should be on a 12/13 degrees transom angle. Poly as the 18 dta you can over the trim the RIB thatís why Humber say never run fully trimmed in.

5 mins on google tells me 12 deg is a very common angle but you can easily find plenty of people who suggest with power trim 15 deg is more useful, and for transom heavy boats even larger angles will help it get on the plane quicker. Now if I think of typical Humber rib itís often got the console far forward and a load of heavy divers and kit aft - so perhaps they developed the range of trim to suit all uses?
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Old 01 November 2017, 20:11   #24
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Callum has said it was 18 degrees hence the issue? i'm no rib designer but 12-14 on google seems the sweet spot so humber may have their reasons to goto 18? maybe Callum has more info on that.

Water in hull on a 1 year old boat isn't ideal obviously, did Humber ever look at the cause of the leak?
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Old 01 November 2017, 21:34   #25
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I've no idea what the transom angle is on my RC, but there are times when I've wished I could trim down further, particularly into a short head sea.
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Old 01 November 2017, 21:36   #26
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Poly I was out of this but:

Sea trial in my 6D combination was not possible.
We did a sea trial when we looked a our first Redbay in a 6.1 with twin 65hp & it was a totally different boat to the 6.1 with the 150GT we ordered, a sea trial can mean very little.

Trimming a RIB I was trained/explained how to drive a 6.1 c/w 150hp by the same naval architect that I explained my experience with in the Humber 6D with the 18dta. Maybe he is wrong but in rough weather we would always be fully trimmed in but on the top of a wave you would throttle off then on the way down then have the throttle fully back on for landing. He had HMS from RIB magazine on our boat from Rathlin to Reday & they played in the waves "one of the most sure-footed craft of it’s size I can remembering handling" (Hugo Montgomery Swan from RIB International)

Did I mention prop torque ? Humber explain this as water in the hull 20 minute talk & after having RIBs for 20+ years I would know if there was water in the hull.

I would trust a naval architect ( McCollam Marine ) with 20+ years of RIB design over a google search any day! We started out in a 5mtr Humber as a dive RIB & after meeting the Redbay & Osprey RIB boys after going from Scotland to Rathlin Island in the 5mtr Humber. I know Redbay have built dive club RIBs, do they change the transom angle for a dive RIB to 18dta.
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Old 04 November 2017, 17:46   #27
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Had my 5.5 destroyer for just short of 10 years now. No build quality problems have shown up thus far though I agree that it is a little rough and ready around the edges compared to allot of the RIBs out there. This is reflected in the price though and nothing has gone wrong with it at all so far...other than the steering cable went this summer.
115 E-tec currently gives 37 knots despite being the XL gearcase with a prop aimed at midrange cruising. 40 knots plus is doable with a different prop but I was after an efficient mid range cruise at about 25 knots. Click image for larger version

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