Avon SeaRider 4m, 70hp, advice please

[Tim Martindale]

I'm considering the purchase of a 20 year old Avon SeaRider 4m RIB but its fitted with an Evinrude 70hp triple, which is the engine its had from new. It strikes me as being a huge engine for a little boat. Is there anything I should be wary of with this set-up. The boat appears to be in good general condition for its age and the vendor is asking £1750 for it. I should add that I'm a novice to RIB ownership although I've been RNLI D-Class crew for 4 years. Any thoughts would be much appreciated.

Many thanks - Tim

[Jelly]

Hi Tim
I aggree a 70Hp on a 4m searider is a bit excessive.
I think they are plated to a max of 40-50Hp - I'm sure some one will correct this.
What is the transom like I have seen lots of that age where the plywood has rotted out.
If you do a search there has been quite a few threads on things to look for buying second hand.
Rgds
James

[Andre]

Avon say in their literature that max 50HP for the SR4.0M Searider and useful 25-40HP

Andre

[Bilge Rat]

Hi Tim

I have a 4.7 searider with a 50 hp 2 stroke Evinrude and my boats rated to take a max HP of 75hp at the transom, i'd think the guys were right and a 70 on a 4 metre was a bit too much, best bet would be to try it out and see, check the transom for cracks and splits and get a good hold of the engine while its locked in the down position and try and lift it up, this will show any weak points in the transom. Have to be aware at this HP to size of boat of chine walking, may need to fit stabilisers or dolphines to keep it steady, a friend of mine runs a 90hp Honda 4 stroke on a 5.5 searider and fitted dolphines to make it more stable and they seem to have done the job. Another point to remember is insurance....if you have aproblem and loose the boat will they pay out if they find out the engine was too big for the boat ?

But hey on another front i bet a 70 on a 4 metre boat will go like the wind and be a lot of fun, if you run it for a year and then it falls apart then you've had a lot of fun, tie the engine to the inside of the boat incase you loose the transom on take off

Rat

[thewavehumper]

Originally posted by Tim Martindale
I'm considering the purchase of a 20 year old Avon SeaRider 4m RIB but its fitted with an Evinrude 70hp triple, which is the engine its had from new.
Many thanks - Tim

Waaa hey that baby will go! Some of the most respected people on this Forum and David Manning have run larger engines on Avons than recommended. ( sorry Dave I couldn't help it), if the engine has been on there that long and the Transoms OK then it's probably going to last a bit longer.

I think 1750 for a 17 year old searider with an 17 year old engine sucks by the way. Where I come from we call that a Rip off. you can do better in the boats for sale pages here or look at Boats and outboards.com

[DM]

Originally posted by THEWAVEHUMPER
( sorry Dave I couldn't help it)

No need to apologise, Stu. I know you're a creature of impulse. But I told gARF what you said and you're in for a good kicking.

I had a plate on my SR 4m which said something about 50hp but I thought that was the minimum rating so I stuck a 70hp Dispirin on it. Likewise with the 5.4 which said something about 90hp so I put a 115 on it with a bit of transom strengthening to go with it.

£1750 with a bit knocked off for luck would be a good buy if its ALL in good condition. They're a bit tight in Sarfhampton so Humper would probably only pay about £750 for it.

His missus told me he was praying to God for a lottery win the other night and God answered him. He said 'Humper, help me out. Buy a ticket'


DM

[Alex Brown]

We have two 4m seariders of probably around 20 year old mark (if not more) down at Neyland YC - they have 25hp suzuki 2-strokes on, which take them quite happily to 23knots at WOT according to my gps when I was sat next to one at speed the other day

The little silver plate does state 50hp max, and I'm not even sure if it even states a weight for the engine too. Looking at the transom, which is held up by two small 45 degree stainless struts with fly nuts holding it together at each end, I really would be concerned about the thing coming off with any more than 40 on there really

When the water has drained out, they're really lively boats even with just the 25hp units bolted on the back, great fun in tight turns, and highly monouverable (sp?). If the 75 has been on the boat you talk about for many years and it's fine with it, that would surely be a wild boat to play with

-Alex

[Phil Davies]

And here's me worrying whether upgrading to a 50hp is stretching it a bit on my 4m Searider!! The maximum rating on this boat is indeed 50hp and the maximum recommended transom weight is 110kg. I would ring Avon and speak to their commercial boat department direct because they warned me about excessive weight on the stern on this particular boat. Also a reputable Avon dealer warned me about the very real possibility of chine walking if the engine is not set up perfectly, and that was just with a 50hp. Personally I would look for a newer boat with more sensible engine as recommended in the above postings.

[slangley]

What is chine walking?

[Richard B]

When the boat skips from side to side at high speed (lands alternatively on the left, then the right chine).

Do a search - there are probably some better explanations and descriptions of cause/cure on older threads.