Humber Destroyer 5.3 auxiliary / kicker

[HMJB]

Hi

I have a Humber Destroyer 5.3 which I usually use in and around the Solent and have a Sea Start membership, so can rely on them, if need towing home.

I'm hoping to do some trips further afield this year and thinking about getting an aux. Ideally I'd like to see if I can get away with mounting one directly to the transom.

I've had them on previous ribs and had to use an adjustable bracket to get the aux clear of the water. Have always found that I have ended up with problems with the bracket from too much bashing around. Maybe I haven't found the right bracket?!?

Wondered whether anyone has mounted an aux directly to the transom (which is my preference) on a Destroyer or if have any recommendations for a good bracket?

Thanks

Hartley

[spartacus]

I'll chip in - I like a good auxilliary thread.

Does your Destroyer transom look like this. Screen-grab from a video on YouTube. (2020 boat)

Usual equation is 1hp per meter but you can increase that. It will push the RIB at displacement speed, if nothing else than to keep you out of danger while you radio for help or get the main engine going. Then consider whether 2-stroke or 4 stroke. 2 strokes will be lighter, usually shallower cowl width. Some including up to 5hp usually have fuel tank built in, but you can carry fuel and oil, or have separate feed tank. You might get away with a standard shaft - I opted for long-shaft.

If the main outboard is a 90hp 2-stoke, then that will help. It's all about having enough clearance for the main unit on hard-lock to hard lock without fouling the auxilliary engine.

The transom thickness may be an issue, measure it and see? Auxilliary outboards will be hand clamped, so that's something to consider.

I fitted a Mariner 4hp (long-shaft) on my Ribcraft 4.8 and it stays there all the time.

Ignore adjustable brackets if you end up going down that route. They rattle like a box of spanners. If you go for a fixed bracket - you may end up getting one fabricated. I was genuinely shocked at the cost of them.

Lastly - if you get the auxillary fitted, then consider putting a ratchet strap around the engine block and through the pull-starter aperture on the cowl and fix on the deck of your Humber with a stainless U bolt. That gives you peace of mind and security so it doesn't end up in the drink!

This is on YamPower's site - 6m Destroyer with auxilliary mounted next to main unit. I assume that's just for transit and it can be mounted directly on the transom in an emergency.
https://www.yampower.co.uk/product/h...rib/#iLightbox[product-gallery]/8

[beerbelly]

Originally Posted by spartacus

I'll chip in - I like a good auxilliary thread.

Does your Destroyer transom look like this. Screen-grab from a video on YouTube. (2020 boat)

Usual equation is 1hp per meter but you can increase that. It will push the RIB at displacement speed, if nothing else than to keep you out of danger while you radio for help or get the main engine going. Then consider whether 2-stroke or 4 stroke. 2 strokes will be lighter, usually shallower cowl width. Some including up to 5hp usually have fuel tank built in, but you can carry fuel and oil, or have separate feed tank. You might get away with a standard shaft - I opted for long-shaft.

If the main outboard is a 90hp 2-stoke, then that will help. It's all about having enough clearance for the main unit on hard-lock to hard lock without fouling the auxilliary engine.

The transom thickness may be an issue, measure it and see? Auxilliary outboards will be hand clamped, so that's something to consider.

I fitted a Mariner 4hp (long-shaft) on my Ribcraft 4.8 and it stays there all the time.

Ignore adjustable brackets if you end up going down that route. They rattle like a box of spanners. If you go for a fixed bracket - you may end up getting one fabricated. I was genuinely shocked at the cost of them.

Lastly - if you get the auxillary fitted, then consider putting a ratchet strap around the engine block and through the pull-starter aperture on the cowl and fix on the deck of your Humber with a stainless U bolt. That gives you peace of mind and security so it doesn't end up in the drink!

This is on YamPower's site - 6m Destroyer with auxilliary mounted next to main unit. I assume that's just for transit and it can be mounted directly on the transom in an emergency.
https://www.yampower.co.uk/product/h...rib/#iLightbox[product-gallery]/8

my 5.5 has that shaped transom its impossible to just clamp directly to the transom and keep it level. So i use what looks like is being used on the pic above its a two piece machined alloy shoe arrangement where one piece bolts to a outboard pad and one to the transom then the outboard pad is dropped into the receiving part on the transom. it needed a little modification to clear the two out board cowls on full lock . my boats currently at my workshop i will take some pics and post them . oh and i have a 3.5hp on my destroyer 5.5 and it will push it along in light seas at 5 knotts i tried a 5 hp and only managed 6 knotts although it got there quicker. i ended up with the 3.5 as its lighter also the 3.5 is a short shaft and when underway the leg is well clear of the water while the 5 long shaft was dragging its leg in the water

[HMJB]

Hi Sparticus / Beerbelly

Thank you for your answers. Yes realised when Sparticus posted the photo, I hadn't thought about the angle of the top of the transom!

Was thinking a 3.5 short shaft 2 stroke. I know everyone always says 1hp per meter, but have successfully used a 3.5 on a 6m in the past and got about 5 knots, as you are finding Beerbelly. I know it is working hard to achieve that and in any sort of sea you're not going to be making that sort of speed, but for the reduced size and weight, I think its worth the trade off.

Would be great to see some photos when you have the chance, as sounds like the right solution for me.

Thanks

[HMJB]

SpartAcus - sorry!

[beerbelly]

Hi couple of pics if they work i initially fitted it a touch low and it was very close the the main outboard on full starboard lock when tilted up so I made a bracket to raise it and a piece of marine ply to stand it out enough

[beerbelly]

Originally Posted by beerbelly

Hi couple of pics if they work i initially fitted it a touch low and it was very close the the main outboard on full starboard lock when tilted up so I made a bracket to raise it and a piece of marine ply to stand it out enough

sorry i dont know why some are sideways and cant figure out how to fix them

[HMJB]

Thanks looks like a good system.

Did you fabricate it yourself, or bought?

[beerbelly]

i bought the 2 parts that slot together and my pal has an engineering company so he knocked up a 10mm stainless plate with threaded holes for me to lift it slightly ill try and find who sells them.and a quick search

https://www.bing.com/ck/a?!&&p=fd37c...dC1raXQv&ntb=1

[spartacus]

Good solution beerbelly.

I hope you get something sorted HMJB.